Synthesis and (co)polymerization of monofluoro, difluoro, trifluorostyrene and ((trifluorovinyl)oxy)benzene

Prog. Polym. Sci. 29 (2004) 75–106 www.elsevier.com/locate/ppolysci

Synthesis and (co)polymerization of monofluoro, difluoro, trifluorostyrene and ((trifluorovinyl)oxy)benzene R. Souzy, B. Ameduri*, B. Boutevin Laboratory of Macromolecular Chemistry, Ecole Nationale Supe´rieure de Chimie de Montpellier, UMR 5076 (CNRS), 8 rue de l’Ecole Normale, 34296 Montpellier Cedex 05, France Received 15 July 2003; revised 3 September 2003; accepted 5 September 2003

Abstract The synthesis of aromatic fluoromonomer compounds functionalized by halogen atoms, organic functions or acid groups prepared and characterized by different methods, are described in this review. This review deals with the synthesis and the polymerization of fluorostyrene bearing the fluorine atom(s) in a and/or b position, mainly. These syntheses involve different reactants such as a,a-difluoroethylbenzene, or aryl iodides and vinylidene fluoride, or styrene and fluorination agents for afluorostyrene and sodium 1,2-difluoroacetate, or triphenylphosphine, fluorotrichloromethane, zinc dust and a ketone for the bfluorostyrene. Their homopolymerizations using different systems (mainly radical and cationic polymerization) and various processes (suspension, emulsion, bulk, or in solution) are also described. The second part reported several synthetic routes to obtain a,b- or b,b-difluorostyrene bearing different reactants such as vinyl zincic reagent (F2CyC(CF3)ZnX (X ¼ Br or I)) and palladium catalysts. This review also describes the synthesis of a,b,b-trifluorostyrene functionalized by a halogen or an acid group, using mainly a cross-coupling reaction between perfluoroalkenylzinc reagent and aryl iodides in the presence of a palladium catalyst. The thermocyclodimerization of a,b,b-trifluorostyrene and the emulsion copolymerization of dimethylphosphonate-4-substitued-a,b,b-trifluorostyrene with a,b,b-trifluorostyrene are studied. Finally, the state of the art of synthesis and (co)polymerization of [(a,b,b-trifluorovinyl)oxy] benzene functionalized or not is described. The main method to obtain such monomer is based on a coupling reaction between functionalized phenate and 1,2-dibromo-tetrafluoroethane (BrCF2CF2Br) followed by a dehalogenation step. The homopolymerization realized by thermocyclodimerization involves fluoropolymers incorporating perfluorocyclobutane groups. These fluoropolymers lead to innovative applications such as membranes for fuel cells, microlithography, and optics. In each part of the review, the specific chemical, physical and thermal properties of all fluoropolymers incorporating aromatic fluoromonomers are reported and discussed. q 2003 Elsevier Ltd. All rights reserved. Keywords: Fluoromonomers; Monofluoro-, difluoro-, trifluorostyrene and ((trifluorovinyl)oxy) benzene; Fluorinated aromatic monomers; Functional monomers; Polymerization; Fluoroaromatic polymers

Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 2. Synthesis and polymerization of monofluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 2.1. Synthesis and polymerization of a-fluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 * Corresponding author. Fax: þ 33-467147220. E-mail address: [email protected] (B. Ameduri). 0079-6700/03/$ - see front matter q 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.progpolymsci.2003.09.002

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2.1.1. Synthesis of a-fluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.2. (Co)polymerization of a-fluorostyrene. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Synthesis and polymerization of b-fluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Synthesis and polymerization of difluorostyrene. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Synthesis and polymerization of a,b-difluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.1. Synthesis of a,b-difluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.2. Polymerization of a,b-difluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Synthesis and polymerization of functional a,b-difluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . 3.3. Synthesis of b-chloro-a,b-difluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4. Synthesis and (co)polymerization of functional b-chloro-a,b-difluorostyrene . . . . . . . . . . . . . . . 3.5. Synthesis and polymerization of b,b-difluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5.1. Synthesis of b,b-difluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5.2. (Co)polymerization of b,b-difluorostyrene. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6. Synthesis and (co)polymerization of 2-benzoyloxypentafluoropropene . . . . . . . . . . . . . . . . . . . . 3.6.1. Synthesis of 2-benzoyloxypentafluoropropene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6.2. (Co)polymerization of 2-benzoyloxypentafluoropropene . . . . . . . . . . . . . . . . . . . . . . . . . 3.7. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Synthesis and polymerization of trifluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1. Synthesis and polymerization of a,b,b-trifluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.1. Synthesis of a,b,b-trifluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.2. (Co)polymerization of a,b,b-trifluorostyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Synthesis and (co)polymerization of [(a,b,b-trifluorovinyl)oxy] benzene . . . . . . . . . . . . . . . . . . . . . . 5.1. Preparation method and (co)polymerization of [(a,b,b-trifluorovinyl)oxy] benzene . . . . . . . . . . . 5.2. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1. Introduction Fluorinated polymers exhibit a unique combination of high mechanical and thermal stability, chemical inertness (to solvents, chemicals, acids and bases), low dielectric constants, excellent weatherability, good resistance to oxidation and very interesting surface properties [1 – 14]. Despite their high price, such product are involved in many high tech applications (aerospace, aeronautics, optics, microelectronics, paints and coatings, engineering and biomaterials, etc.). Many fluorinated monomers have been synthesized and commercialized. Most commercially available fluoroalkenes are tetrafluoroethylene (TFE), vinylidene fluoride (VDF), chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), and in less extent, hexafluoroisobutylene (HFIB), 3,3,3-trifluoropropene (TFP), and perfluoroalkylvinyl ethers (PAVE).

78 79 80 81 81 81 81 81 82 83 83 83 83 84 84 84 85 85 86 87 87 88 92 92 93 99 100 101 101

Among them, we have found it worth studying the synthesis of aromatic fluoromonomers and hence their polymerization. In this review, we have focused the preparation of fluoroaromatic monomers, and especially those that possess the fluorine atoms linked to the ethylenic carbon atoms. Although the synthesis and the polymerization of aromatic monomers bearing fluorine atoms or fluorinated substituents on the aromatic ring also represent a relevant class of aromatic fluoromonomers. Interestingly, electronwithdrawing groups such as fluorine atom or a trifluoromethyl group in para position of the double bond, enabled the corresponding fluoroaromatic monomers to undergo faster radical polymerization [15]. Wooley et al. [16,17] copolymerized MMA with 4-fluorostyrene by atom transfer radical polymerization (ATRP) to yield nanostructured materials with fluorine tags at various sites within the material.

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106

Nomenclature AIBN ATRP BPFP CTFE DMAc DMF DPn DSC FA HFIB HFIP HFP

azobisisobutyronitrile atom transfer radical polymerization 2-benzoyloxypentafluoropropene chlorotrifluoroethylene dimethylacetamide dimethylformamide average degree of polymerization in number differential scanning calorimetry fluoroacrylates hexafluoroisobutylene hexafluoroisopropanol hexafluoropropene

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MMA methyl methacrylate Mn average molecular weight in number Mw average molecular weight in weight PAVE perfluoroalkylvinyl ether PFCB perfluorocyclobutane PMVE perfluoromethylvinyl ether RT room temperature TEMPO 2,2,6,6-tetramethyl piperidinyl-1-oxyl Tg glass transition temperature TFE tetrafluoroethylene TFP 3,3,3-trifluoropropene TFS trifluorostyrene TGA thermal gravimetric analysis VDF vinylidene fluoride UV ultra violet

In addition, other fluoroaromatic sytrenes as (1) (Fig. 1), containing meta and para isomers) were involved in nitroxyl mediated polymerization in the presence of TEMPO as counter radical and fluoropolystyrene thus obtained was also able to act as an original initiator for the synthesis of diblock copolymers [18,19]. Such fluoro-diblock copolymers were used for supercritical carbon dioxide application [18]. As for, 2,3,4,5,6-pentafluorostyrene, many studies have been reported. This monomer was polymerized anionically [20] or under plasma conditions [21,22]. In addition, a number of studies of radical copolymerization with styrene, likewise traditional radical polymerization [23], or ATRP was extensively investigated by Jankova et al. [24,25]. Deposits from 4-fluorostyrene by vapor deposition [26] or with glycidyl methacrylate [27] were also published. In the past few decades, much attention has been focused in the preparation of fluoropolymers incorporating aromatic fluoromonomers (2) (Fig. 2), because of the characteristic effects of the aromatic group (e.g. increasing the Tg and the thermostability of the polymer obtained) and fluorine substitution on the physico-chemical properties. Initially synthesized in 1949 by Cohen et al. [28], aromatic fluorinated monomers, like fluorinated

styrenes, are useful building blocks in organofluorine chemistry. They have led to numerous investigations, and have found applications as monomers [29], as precursors for flame retardant materials [30], and in fertilizer compounds [31]. The objective of this review deals with the synthesis and the (co)polymerization of functional aromatic fluoromonomers (2) (Fig. 2). First, the synthesis and the (co)polymerization of monofluorostyrene such as a- or b-fluorostyrene is presented. The second part concerns the preparation of difluorostyrene and its (co)polymerization. Finally, a review of the synthesis of a,b,b-trifluorostyrene and [(a,b,btrifluorovinyl)oxy] benzene is devoted.

Fig. 1. Formula of fluoromonomer (1).

Fig. 2. General structure of functional aromatic fluoromonomers (2).

2. Synthesis and polymerization of monofluorostyrene This first section seeks to report the synthesis and the (co)polymerization of monofluorostyrene. It covers in a first part the synthesis and

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Scheme 1. Synthesis of a-fluorostyrene according to Matsuda et al. [32].

(co)polymerization of a-fluorostyrene and in a second part, the preparation of b-fluorostyrene. 2.1. Synthesis and polymerization of a-fluorostyrene 2.1.1. Synthesis of a-fluorostyrene This monomer was first synthesized and polymerized in 1962 by Matsuda et al. [32]. Their synthetic routes are based on a pyrolysis of a,adifluoroethylbenzene. These authors did first

synthesize a,a-difluoroethylbenzene by different methods shown in Scheme 1. Of their four methods for preparing a,a-difluoroethylbenzene, the second one (Eq. (2), Scheme 1) was the most convenient and gave yields of 40 –45% with phenylacetylene conversion of almost 100%. a,a-Difluoroethylbenzene is a mobile, colorless liquid with b.p. 64.6 –66 8C (40 mm Hg). It is stable in the presence of bases such as tetramethylguanidine at 160 8C and with molten moist sodium hydroxide at 235 8C. According to the authors [32], the preparation of afluorostyrene was best effected by a two path procedure in which the vapors of a,a-difluoroethylbenzene, diluted with an equal volume of nitrogen, were passed through the pyrolysis zone of a stainless steel or Monel metal reactor at 350– 400 8C with a space velocity of about 25 l gas liter volume pyrolysis zone per hour. To achieve the best results, authors used a clean metal wall. A 53% yield of a-fluorostyrene was obtained at 83% overall conversion of a,a-difluoroethylbenzene. a-Fluorostyrene is a colorless liquid with b.p. 45.0 – 45.4 8C (14 mm Hg). It is a stable compound in aqueous alkali at 100 8C but is even more readily hydrolyzed than a,a-difluoroethylbenzene to acetophenone in the presence of acids. At the beginning of the 1990s, Heitz et al. [33 –35] described the synthesis of different functionalized a-fluorostyrenes based on the Heck reaction [36]. The general synthetic route, using iodoarenes and vinylidene fluoride of the synthesis is described in Scheme 2. In 2000, Meyer et al. [37] proposed a new synthetic route for the synthesis of monofluorinated monomers and a-fluorostyrene. Such last monomers are

Scheme 2. Synthesis of functional a-fluorostyrenes according to Heitz and Knebelkamp [33–35].

Scheme 3. Synthesis of a-fluorostyrene according to Meyer et al. [37].

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106 Table 1 Yields of synthesis of a-fluorostyrene according to Meyer et al. [37] Olefins

R1

R2

Bromofluorides 2

Ratios of regioisomers

Vinyl fluoride 3

Yield (%)

1a 1b 1c 1d

Ph p-Cl –Ph Ph C4H9

H H Me H

2a 2b 2c 2d

. 99:1 . 99:1 . 99:1 95:5

3a 3b 3c 3d

80 64 71 64

Scheme 4. Cyclopropanation reaction of a-fluorostyrene according to Meyer et al. [37].

available by bromofluorination of alkenes and subsequent dehydrobrominaion of the thus-formed vicinal bromofluorides [38,39]. The fluorination agent is trialkylamine/HF complexes (Me3N/HF) in combination with N-bromosuccinimide (NBS), since these reagents gave high yields (Scheme 3). These authors [37] prepared different vinyl fluorides in good yields (see Table 1). In addition, Meyer et al. [37] carried cyclopropanation reaction on a-fluorostyrene (Scheme 4). Remark. The cyclopropyl group is known to have biological activity and is present in a large number of naturally occurring compounds [40]. Bogachev et al. [41] reported also Diels Alder reactions with a- and b-fluorostyrene to lead to compounds incorporating a cyclopropyl group. 2.1.2. (Co)polymerization of a-fluorostyrene Matsuda et al. [32] investigated polymerization of a-fluorostyrene. A number of procedures to prepare homopolymers of a-fluorostyrene were attempted. The first one concerned the radical bulk polymerization initiated by azobisisobutyronitrile at 70 8C or with ultra violet light at room temperature

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yielded dark mixtures from which hydrogen fluoride was released. Only small amounts of a yellow, unsaturated polymer were isolated from these mixtures. It appeared that some of the monomer was polymerized but the polymer underwent dehydrofluorination to give a polyconjugated material according to Scheme 5. In 1982, Majumdar et al. [42] reported and confirmed on general instability of poly(a-fluorostyrene) prepared either by bulk radical polymerization or cationic polymerization techniques, in most organic solvents. The second procedure to prepare poly(a-fluorostyrene) dealt with the emulsion polymerization under buffered neutral or alkaline conditions [32]. It was found that high molecular weight polymers containing the theoretical amount of fluorine could be prepared in such systems [43]. Authors developed two convenient procedures [32], the first one employing a potassium persulfate catalyst buffered at pH 7, in which the persulfate was decomposed thermally at 50 8C, and the second one in which the initiating system was ammonium persulfate activated with triethanolamine buffered at pH 9. The DPn was not calculated but the intrinsic viscosity measurements of poly(a-fluorostyrene) samples, equal to 0.8– 1.2 dl/g, indicate an appreciable molecular weight. The poly(a-fluorostyrene) samples were soluble in usual solvent for polystyrenes, stable below its softening point (145 –150 8C), but on prolonged heating above this latter, hydrogen fluoride was released. At last, according to Matsuda et al. [32], the pyrolysis of poly(a-fluorostyrene) of known structure and molecular weight would, therefore, appear to be a good synthesis for the conjugated polymer of phenylacetylene. Heitz et al. [33 – 35] described in a first way, the cationic homopolymerization of a-fluorostyrene. The poly(a-fluorostyrene) is a pale yellow-green material. The GPC analysis revealed the following molecular weights: Mw ¼ 23; 000 and Mn ¼ 7200: In

Scheme 5. Radical polymerization of a-fluorostyrene followed by dehydrofluorination.

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determined the Alfrey – Price Q – e values [44] for afluorostyrene are Q ¼ 2:49 and e ¼ 22:04: These results indicate that a-fluorostyrene is an electron rich monomer. Scheme 6. Synthesis of poly(a-fluorostyrene) by emulsion polymerization [33].

2.2. Synthesis and polymerization of b-fluorostyrene

a second way, these authors [33 – 35] carried out the radical bulk polymerization of these monomers. And as above, the GPC analysis showed low molecular weights: Mw ¼ 12; 500 and Mn ¼ 6250: In a third way, the German group [33 –35] prepared poly(a-fluorostyrene) using a buffered emulsion systems (Scheme 6). Yields (fair to good) and molecular weights (40,000 up to about 2,700,000 g/mol) of each poly(a-fluorostyrene) [33] are presented in Table 2. Although rather high Tg were obtained (up to 171 8C), the polymers were not thermostable. Finally, Heitz et al. [33], investigated the kinetics of copolymerization initiated by AIBN in toluene of a-fluorostyrene with styrene and with methyl methacrylate to assess the reactivity ratio of a-fluorostyrene. Results of the copolymerization of a-fluorostyrene/ styrene are presented in Table 3. With a-fluorostyrene (defined as M1 ), the reactivity ratios were r1 ¼ 0:196 and r2ðstyreneÞ ¼ 1:085: Based on the reactivity ratios, these authors

In 1953, Prober [45] reported the synthesis of bfluorostyrene substituted in a-position by a chlorine atom. Scheme 7 describes the multi-step synthetic route. This a-chloro-b-fluorostyrene monomer was obtained in 52% yield. But, the author did not report the (co)polymerization of a-chloro-b-fluorostyrene. In 1977, Van Hamme et al. [46] reported the synthesis of the cis and trans-a-trifluoromethyl-b,bfluorochlorostyrene and b,b-chlorofluorostyrene. The synthesis was based on a in situ Wittig reaction between triphenylphosphine, fluorotrichloromethane, zinc dust and an aldehyde or ketone in dimethylformamide (Scheme 8). Table 4 summarizes the yields of the reaction [46] described above in Scheme 8. The cis and trans-a-trifluoromethyl-b,b-fluorochlorostyrene prepared in similar conditions is described in Scheme 9. The author obtained this potential monomer in a 71% yield but no copolymerization was achieved.

Table 2 Yields and molecular weights of copolymers of a-fluorostyrene with various comonomers [33] R

Monomer synthesis yield (%) Polymerization yield (%) Mw

H 4-MeO 4-iPr 4-F 4-Me 2-Me 3-Me 2-F 2-Cl 2-MeO 2,4-Me 4-Cl

39 60 47 33 31 45 48 72 – – – –

a

76 60 80 60 58 71 70 75 61 70 53 71

Td stands for decomposition temperature. Decomposition before Tg :

Mn

216,000 63,000 352,000 193,000 394,000 165,000 461,000 297,000 425,000 174,000 60,000 21,000 320,000 176,000 749,000 341,000 79,000 29,000 118,000 38,000 40,000 14,000 2,694,000 1,425,000

Mw =Mn Tg (8C) DSC Td (8C) TGA Dm (%) 3.43 1.82 2.39 4.92 2.44 2.86 1.82 2.20 2.72 3.10 2.86 1.89

120 –a 116 122 122 144 110 158 171 –a 149 140

185 130 183 177 192 187 203 – – 211 193 220

16.7 13.3 12.3 14.1 14.6 14.7 14.2

13.3 13.6 13.8

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Table 3 Results of the copolymerization of a-fluorostyrene with styrene [33] Content of a-fluorostyrene in feed (mol%)

Reaction time (min)

Conversion (%)

Content of a-fluorostyrene in copolymer (mol%)

9.31 16.42 24.60 39.22 45.29 77.70 89.51

25 25 25 25 25 85 90

1.5 2.0 1.9 1.2 1.2 5.8 2.9

6.65a 13.75 21.04 28.85 32.01 60.00b 68.88

a b

MwðaverageÞ ¼ 12; 000 and MnðaverageÞ ¼ 7800: MwðaverageÞ ¼ 8800 and MnðaverageÞ ¼ 6200:

2.3. Conclusion The proposed synthetic routes for the preparation of a- and b-fluorostyrene involve different compounds such as a,a-difluoroethylbenzene, aryl iodides or ketones and triphenylphosphine and sometimes multi-step procedures. However, it is clear that the (co)polymerization of a-fluorostyrene leads to polymers, having different molecular weights depending on the initiations and the process used. Yet the lack of thermal stability (since dehydrofluorination occurs) is a limitation or the corresponding polymers. To our knowledge, the copolymerization of b- and functional b-fluorostyrene with commercially available or synthesized comonomers was not investigated, probably because of its poor reactivity compared to that of afluorostyrene.

3. Synthesis and polymerization of difluorostyrene The synthesis and the (co)polymerization of substituted and non-substituted a,b-difluorostyrene

Scheme 8. Synthesis of cis and trans-a-trifluoromethyl-b,bfluorochlorostyrene, and b,b-chlorofluorostyrene according to Van Hamme and Burton [46].

is reported and discussed in this second section. In this subsection, six main kind of difluorstyrenic compounds have been considered: (i) a,b-difluorostyrene, (ii) functional a,b-difluorostyrene, (iii) b-chloro-a,bdifluorostyrene, (iv) functional b-chloro-a,b-difluorostyrene, (v) b,b-difluorostyrene, (vi) 2-benzoyloxypentafluoropropene including their syntheses and their (co)polymerizations. 3.1. Synthesis and polymerization of a,b-difluorostyrene 3.1.1. Synthesis of a,b-difluorostyrene In 1953, Prober [45] pioneered the synthesis of aromatic fluoromonomers and particularly the synthesis of difluorostyrene like a,b-difluorostyrene and b,b-difluorostyrene. The first step of his synthesis was the preparation of difluoroacetophenone ((10-1), Scheme 10) prepared several years before by Cohen et al. [28]. The formation of a,a-dichloro-b,bdifluoroethylbenzene ((10-2), Scheme 10) was favored by slow heating with phosphorus pentachloride. Compound (10-3) (Scheme 10) was synthesized by reaction of (10-2) with antimony trifluoride. The dehalogenation of (10-3) resulted a,b-difluorostyrene (10-4) in a 41% yield. 3.1.2. Polymerization of a,b-difluorostyrene Prober [45] homopolymerized this a,b-difluorostyrene monomer by boron trifluoride, but the polymer was thermally unstable. However, no detail was given Table 4 Experimental conditions and yields of the synthesis of RR0 CyCFCl monomers [46]

Scheme 7. Synthesis of a-chloro-b-fluorostyrene according to Prober [45].

R

R0

Time of reaction (h)

Yield (%)

Ph Ph n-C6H13 Ph

CF3 H H H

24 115 89 96

71 64 49 15

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Scheme 9. Synthesis of cis and trans-a-trifluoromethyl-b,b-fluorochlorostyrene according to Van Hamme and Burton [46].

concerning the molecular weights or polydispersity index. 3.2. Synthesis and polymerization of functional a,b-difluorostyrene After describing the synthesis of multi-fluorinated styrenes, such as a,b,b-trifluorostyrene and 1-arylperfluoropropenes [47], or b,b-difluoro-a-(trifluoromethyl)styrenes [48], Davis and Burton [49,50] coupled fluorozincic olefins such as (E)-HFCyCFZnI with substituted aromatic iodides, under mild conditions, in the presence of catalytic Pd(PPh3)4 in DMF to give (Z)-a,b-difluorostyrene (11-5) in a stereoselective way (Scheme 11).

First, the authors prepared (E)-1,2-difluoroethylenyliodide ((11-2), Scheme 11) from the cleavage with KF/I2 of (E)-HFCyCFSiEt3 ((11-1), Scheme 11) which was prepared from bromo or chlorotrifluoroethylene [51,52]. In a second step, alkene ((11-2, Scheme 11) was treated with zinc metal in DMF to give (11-3) in a 55– 63% yield. This excellent thermal stable synthon (11-3) was finally coupled with different substituted aryl iodides (11-4) to give functionalized (Z)-a,b-difluorostyrene (11-5) in fair to good yields according to the electroinductive substituent and its position on the ring (Table 5). Davis and Burton [50] also described the catalytic mechanism in 1997. In 2000, Liu and Burton reported [53] a general and stereospecific method for the preparation of substituted

Scheme 10. Synthesis of a,b-difluorostyrene, b,b-difluorostyrene, and a,b,b-trifluorostyrene by Prober [45].

Scheme 11. Synthesis of functional (Z)-a,b-difluorostyrene according to Davis and Burton [49,50].

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106 Table 5 Yields of synthesis of functionalized (Z)-a,b-difluorostyrenes [49,50] ArI

Product

Yield (%)

C6H5I p-MeOC6H4I p-NO2C6H4I o-NO2C6H4I o-CH3C6H4I p-EtOC6H4I p-CH3C(O)C6H4I m-ClC6H4I 1,4-C6H4I2 p-CF3C6H4I o-(iPr) C6H4I

C6H5CFyCFH p-MeOC6H4CFyCFH p-NO2C6H4CFyCFH o-NO2C6H4CFyCFH o-CH3C6H4CFyCFH p-EtOC6H4CFyCFH p-CH3C(O)C6H4CFyCFH m-ClC6H4CFyCFH 1,4-C6H4CFyCFH p-CF3C6H4CFyCFH o-(iPr) C6H4CFyCFH

65 88 66 78 72 93 71 60 80 70 55

(E)-a,b-difluorostyrene ((12-5), Scheme 12). To the difference with previous Burton’s investigation [49, 50], the starting silicon-containing olefin (12-1) was a (Z)-isomer. The synthesis was based on the coupling between (Z)-HFCyCFZnI and aryliodides in DMAc in the presence of Pd(PPh3 ) 4/CuBr co-catalysis (Scheme 12). The addition of CuBr accelerate the palladium-catalyzed reaction because it presumably complexes the triphenylphosphine ligands and generates a higher concentration of the active catalyst. Table 6 summarizes the yields obtained by the authors [53] for the reaction described above. Remark. In late 1970s, Naae [54,55] reported the electrophilic bromination of a,b-difluoro and substituted a,b-difluorostyrene. The (co)polymerization of substituted a,b-difluorostyrene was not reported. 3.3. Synthesis of b-chloro-a,b-difluorostyrene In 1956, Dixon [56] described the synthesis of different fluoroolefins and particularly that of

83

b-chloro-a,b-difluorostyrene. This author reported that chlorotrifluoroethylene reacted with phenyl lithium to eliminate lithium fluoride and gave bchloro-a,b-difluorostyrene in a 60% yield instead of the stylbene derivative (Scheme 13). The (co)polymerization of b-chloro-a,b-difluorostyrene was not investigated by the authors. 3.4. Synthesis and (co)polymerization of functional b-chloro-a,b-difluorostyrene In the 1970s, Rybakova et al. [57,58] reported a similar synthetic route (Scheme 14) for the synthesis of b-chloro-a,b-difluorostyrene. The metal used by the authors was magnesium. The yield of the reaction was low (10%). However, the (co)polymerization was not investigated by the authors. In 1976, the Timofeyuk’s team [59] achieved the synthesis of b-chloro-a,b-difluorostyrene functionalised in para-position by a sulfonic acid in a 97% yield (Scheme 15). However, these authors did not polymerize such compounds. The coupling reaction (Scheme 16) of p-lithio-a,bdifluoro-b-chlorostyrene with a,b-difluoro-b-chlorostyrene to give oligomers ArCF( –C6H4CFyCF – )nCl, where Ar ¼ C6H5 or C6H5C6H4 was successfully achieved by Panov et al. in 1972 in 7% yield only [57,60,61]. The experimental conditions and the physico-chemical properties of such compounds are described in the paper. 3.5. Synthesis and polymerization of b,b-difluorostyrene 3.5.1. Synthesis of b,b-difluorostyrene In 1953, Prober [45] reported the synthesis of b,b-difluorostyrene in a multi-step synthetic route (Scheme 10). The synthesis of the b,b-difluorostyrene (10-6) was first based on the preparation of the synthon

Scheme 12. Synthesis of (E)-a,b-difluorostyrene by Liu and Burton [53].

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Table 6 Yields of synthesis of (E)-a,b-difluorostyrene by Liu and Burton [53] R

Product

Isolated yield (%)

p-F p-Cl p-Br p-I H p-OMe m-CF3 o-Naphathalene m-NO2 p-NO2 m-Thiophene

p-FC6H4CFyCFH p-ClC6H4CFyCFH p-BrC6H4CFyCFH p-IC6H4CFyCFH C6H5CFyCFH p-MeOC6H4CFyCFH m-CF3C6H4CFyCFH o-Naphthalene –CFyCFH m-NO2C6H4CFyCFH p-NO2C6H4CFyCFH m-Thiophene–CFyCFH

89 95 94 92 74 94 84 87 93 87 73

Scheme 13. Synthesis of b-chloro-a,b-difluorostyrene by Dixon [56].

((10-1), Scheme 10), whose is described in paragraph 3-1. Compound (10-5) was obtained after a Meerwein –Ponndorf– Verley reduction of (10-1). At last, a pyrolysis (600 8C) of (10-5) gave the desired monomer (10-6) in 10% yield. In 1993, Morken et al. [48] described the preparation of b,b-difluoro-a-(trifluoromethyl)styrene by palladium-catalyzed coupling of aryl iodides with pentafluoroprope-2-ylzinc reagent. These authors prepared in 1991 [62] the first internal vinyl zincic reagent (F2CyC(CF3)ZnX (17-3); X ¼ Br or I) by dehalogenation/metalation of CF3CBr2CF3 (17-2) by zinc in DMF or triglyme (Scheme 17). The zinc reagent ((17-3), Schemes 17 and 18) reacted smoothly with aryl iodides in DMF solvent in

the presence of a 3 – 5 mol% Pd(PPh3)4 catalyst (Scheme 18). This coupling reaction was achieved with different substituted aryl iodide compounds. Table 7 summarizes isolated yields of substituted b,b-difluoro-a(trifluoromethyl)styrene (18-1). The (co)polymerization of (18-1) was not investigated by the authors. 3.5.2. (Co)polymerization of b,b-difluorostyrene The emulsion polymerization of b,b-difluorostyrene was investigated in 1952 by Prober [45]. It was carried out in sealed tubes at 50 –55 8C, 72 h, in presence of emulsifier (sodium tetraborate decahydrate: ‘Ivory soap’, Aerosol OT or dodecylamine hydrochloride) and of potassium persulfate. But it led to low yields of a thermally stable polymer. The softening points of each poly(b,b-difluorostyrene) were ranged between 207 and 220 8C (depending on the emulsifier agent). 3.6. Synthesis and (co)polymerization of 2-benzoyloxypentafluoropropene 3.6.1. Synthesis of 2-benzoyloxypentafluoropropene In 2002, Guiot et al. [63] reported the synthesis of 2-benzoyloxypentafluoropropene (BPFP, F 2CyC(CF3 )OCOC 6H 5). The preparation of F2CyC(CF3) – OR monomers were pioneered by Bekker et al. [64,65] in 1975. To achieve the synthesis of BPFP ((19-3), Scheme 19), the authors reported a synthetic route based on Nakai et al.’s synthesis [66 –68] which concerned a dehydrofluorination of hexafluoroisopropanol ((19-1), Scheme 19, HFIP), followed by the addition of acid chloride according to Scheme 19. Table 8 reports the results of the synthesis of monomer (19-3).

Scheme 14. Synthesis of b-chloro-a,b-difluorostyrene by Rybakova et al. [57].

Scheme 15. Functionalization of b-chloro-a,b-difluorostyrene by Timofeyuk et al. [59].

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106

85

Scheme 16. Coupling reaction of p-lithio-a,b-difluoro-b-chlorostyrene with a,b-difluoro-b-chlorostyrene by Panov et al. [61].

Scheme 17. Synthesis of b,b-difluoro-a-(trifluoromethyl)styrene according to Morken et al. [62].

Remark. Nakai and Maruta [66] mentioned that such monomers exhibits agricultural properties. 3.6.2. (Co)polymerization of 2-benzoyloxypentafluoropropene Narita et al. [69 – 71] carried out an anionic homopolymerization of F2CyC(CF3)OCOC6H5 without any success. Guiot et al. [63] also described the radical copolymerization of 2-benzoyloxypentafluoropropene (BPFP) with vinylidene fluoride (VDF) initiated by tert-butyl peroxypivalate. A series of 11 copolymerizations were achieved from [VDF]0/([VDF]0 þ [BPFP]0) initial molar ratios ranging from 19 to 99 mol% (Table 9). From Tidwell and Mortimer method [72], these authors determine the activity ratios ri of both comonomers: rVDF 0:770:40 and rBPFP 0:110:32: From Alfrey and Price equation [44], the authors calculated the Q – e values of BPFP and compared with those VDF-comonomer systems (Table 10). According to the authors [63], the Q and e values of BPFP (eBPFP ¼ 2:27 and QBPFP ¼ 0:081) show that for BPFP monomer, the double bond exhibits a poor electrical charge and confirms that the fluorine atoms and trifluoromethyl group does not stabilize the radical by resonance.

Scheme 18. Reaction of coupling between fluoroalkenyl zinc and aryl iodides [62].

3.7. Conclusion This second part was devoted to the synthesis of difluorostyrene such as a,b- or b,b-difluorostyrene. Among the proposed synthetic routes, one of the most interesting way to achieve the synthesis was based on a cross-coupling reaction between zinc reagent such as (E) or (Z) XYCyCW – ZnT (X, Y, W: H, CF3 or F and T: Br or I) as extensively investigated by Burton’s group, and functional aryl iodides in presence of palladium catalyst. However, the polymerization of a,b-difluorostyrene was pioneered by Prober in 1953. The introduction of fluorine atom in b-position is astute in order to favor the copolymer of a,b-difluorostyrene since its reactivity is lower than that of a-fluorostyrene. Actually, a-fluorostyrene is too reactive to allow a nice copolymerization and usually poly(a-fluorostyrene) are obtained. On the other hand, to our

Table 7 Yields of synthesis of b,b-difluoro-a-(trifluoromethyl)styrene [62] b,b-difluoro-a-(trifluoromethyl)styrene

Isolated yields (%)

C6H5C(CF3)yCF2 p-NO2C6H4C(CF3)yCF2 m-NO2C6H4C(CF3)yCF2 o-NO2C6H4C(CF3)yCF2 o-MeOC6H4C(CF3)yCF2 p-MeOC6H4C(CF3)yCF2 p-BrC6H4C(CF3)yCF2 3,5-(CF3)2C6H3C(CF3)yCF2 m-ClC6H4C(CF3)yCF2 p-EtO2CC6H4C(CF3)yCF2 p-CH3C6H4C(CF3)yCF2 o-FC6H4C(CF3)yCF2 p-CF2yC(CF3)C6H4C(CF3)yCF2

62 75 72 38 68 64 66 45 73 66 64 63 66

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Scheme 19. Synthesis of 2-benzoyloxypentafluoropropene according to Nakai and Maruta [66]. Table 8 Yields of synthesis of 2-benzoyloxypentafluoropropene by Guiot et al. [63] Experiment No.

Synthesis of F2CyC(CF3)–O2/Liþ experimental conditions

Eq. Cl– Bz in the synthesis of F2CyC(CF3) –OBza

Yields of F2CyC(CF3) –OBz (%)

1 2 3

1 h at 250 8C, 20 min at 20 8C, diethyl ether 10 min at 278 8C, 20 min at 20 8C, diethyl ether 1 h at 278 8C, 20 min at 20 8C, diethyl ether

1.2 1.2 1.2

54 76 81

a

Experimental conditions: 2 h at room temperature.

knowledge, the synthesis and the (co)polymerization of HFCyC(CF3)(X)Ar (X: oxygen, sulfur) has never been investigated. Finally, the copolymerization of functional b,b-difluorostyrene like BPFP with VDF was encouraging that is why more investigations have been devoted to a,b,b-trifluorostyrene and derivatives.

been reported. In addition, it was worth describing the synthesis of [(a,b,b-trifluorovinyl)oxy] benzene and its (co)polymerization since, as in aliphatic series, it should be expected that this latter is more reactive than TFS. Table 10 e and Q values of fluoroalkenes [63]

4. Synthesis and polymerization of trifluorostyrene

Monomer

e

Q

Reference

Regarding a,b,b-trifluorostyrene (TFS), various ways of synthesis and its (co)polymerization have

H2CyCHCF3 HFCyCH2

0.42 0.72 20.05 0.40 0.50 1.20 2.10 1.15 1.52 2.24 1.04 1.14 (1.23) 1.68 1.56 1.84 1.48 1.20 3.01 4.09 1.22 1.63 1.84 2.27 0.58

0.130 0.008 0.016 0.008 0.015 0.036 0.002 0.009 0.011 0.075 0.008 0.060 (0.040) 0.045 0.026 0.031 0.020 0.048 0.250 0.047 0.049 0.032 0.031 0.081 0.820

[73] [73] [74] [74] [75] [76] [77] [74] [78] [79] [78] [80] [81] [73] [74] [82] [73] [83] [73] [84] [73] [74] [63] [73]

F2CyCH2 Table 9 Monomer/copolymer composition of VDF/BPFP system determined by 19F NMR spectroscopy [63] VDF in feed (mol%)

VDF in the copolymer (mol%)

99.2 98.5 96.2 92.8 88.5 84.2 75.6 66.5 56.6 39.8 19.0

99.6 98.8 96.8 93.5 91.9 86.3 73.6 71.5 62.8 48.5 48.4

Copolymerization conditions [t Bu – OO – CO – t Bu]0 / ([VDF]0 þ [BPFP]0) ¼ 2%, 50 8C, 16 h.

CF3CFyCFH (cis) F2CyCFH F2CyCFCH2OH F2CyCFC3H6OH F2CyCFC3H6OAc F2CyCFC3H6SAc F2CyCFCl

F2CyCFCO2CH3 F2CyCFOCF3 F2CyCFCF3 F2CyCF2

F2CyCF(CF3)OBz F2CyCF–CFyCF2

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106

Fig. 3. Formula of functionalized and non-functionalized a,b,btrifluorostyrene.

4.1. Synthesis and polymerization of a,b,b-trifluorostyrene In this review, the state of the art of a,b,btrifluorostyrene and TFS funtionalized by halogens, organic functions and acid groups is presented (Fig. 3). 4.1.1. Synthesis of a,b,b-trifluorostyrene The synthesis of such a monomer was reported for the first time in 1949 by Cohen et al. [28]. The first reaction of the multiple-step synthetic route (Scheme 20) required benzene, trihalogeno acid chloride and Lewis acid to catalyze the electrophilic aromatic substitution. The second and the third steps are chlorination and halogen substitution, respectively. At last, a,b,b-trifluorostyrene was obtained in a 48% yield. Four years later, Prober [45] was the second author to propose new synthetic routes of fluorinated styrenes like a,b,b-trifluorostyrene (10-7), b,b-difluorostyrene (10-6), a,b-difluorostyrene (10-4) and a-chlorob-fluorostyrene. a,b,b-trifluorostyrene was synthesized starting from sodium difluoroacetate [45] (Scheme 10).

87

In 1956, Dixon [56] proposed a general synthetic method to prepare a,b,b-trifluorostyrene. Such method was reutilized in 1961 by Kazennikova et al. [85]. a,b,b-Trifluorostyrene was obtained with low yields after a reaction between aryllithium reagents with tetrafluoroethylene. The low yields arose from the competition of the styrenes with tetrafluoroethylene for the ArLi, which gave stylbenes. In 1976, Rybakova et al. [86] investigated the synthesis of such compounds. They were prepared from a (vinyl phenyl)silane with trimethyl-silyl chlorosulfonate, at 2 30 8C. The reaction went in accordance with Scheme 23. The second step consists in a hydrolysis of the sulfonic ester. The a,b,btrifluorostyrene funtionalized by a sulfonic acid was obtained with good yields (Scheme 21). In 1982, Sorokina et al. [87] developed a synthesis of a,b,b-trifluorostyrene by using an organostanic (organic tin) compound and aryl iodide (Scheme 22). The highest yield of trifluorostyrene was observed when the reaction achieved in HMPTA and DMFA. Reactions were catalyzed with PhPdI(PPh3)2 and Pd(PPh3)4. In 1988, Heinze and Burton [47] reported results of synthesis and characterization of arylalkenes. They coupled perfluoroalkenylzinc reagents [F2CyCFZnX, (Z)-F 3C – CFyCF – ZnX, (E)-F3C – CFyCF – ZnX with X equivalent of bromide or iodide] with aryl iodides in the presence of a catalyst: Pd(PPh3)4 [88] to give the corresponding arylalkenes (Scheme 23).

Scheme 20. Synthesis of a,b,b-trifluorostyrene according to Cohen et al. [28].

Scheme 21. Rybakova et al. synthesis [86].

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Scheme 22. Sorokina et al. synthesis [87].

These authors synthesized in good yields a series of substituted a,b,b-trifluorostyrenes (Table 11) because they worked at low temperature and they avoided the cyclodimerization phenomena [89 – 91] (Scheme 24). Their procedure also offers significant advantages like: the zinc reagents seems simple to prepare in triglyme, DMF or THF. According to the authors, Pd(PPh3)4 catalyst is the critical factor. After different studies based on commercial catalysts [88] and noncommercial catalysts prepared in situ according to Coulson [92], Heinze and Burton [47] explained completely the catalyst mechanism and showed the best experimental conditions conducting to very good yields. Burton et al. did not investigate the functionalization of TFS by a sulfonic acid, but in 1997, Ballard Power System Inc. deposited a patent [93] which dealt with the synthesis and the copolymerization with trifluorostyrene of p-chloro or fluorosulfonatea,b,b-trifluorostyrene. The corresponding sulfonic acid component was obtained by hydrolysis of the p-halogenosulfonate-a,b,b-trifluorostyrene. The synthesis of this monomer was based on the following reaction scheme (Scheme 25). The synthesis scheme was based on different research group. First, the action chlorosulfonic acid on iodobenzene was achieved from the Sanecki’s synthesis [94] and the chlorosulfonate or fluorosulfonate trifluorostyrene compound is obtained with a Burton organozincic reactant [47]. The second chemical step was based on a cross-coupling reaction between perfluoroalkenylzinc reagents with chlorosulfonic aryl iodides catalyzed with tetra(triphenylphosphine)palladium. The perfluoroalkenylzinc reagents are simple to prepare and thermally stable [95,96].

4.1.2. (Co)polymerization of a,b,b-trifluorostyrene Prober [45] also polymerized a,b,b-trifluorostyrene initiated by several radical organic initiators (Table 12) (in bulk for 72 h in the presence of benzoyl peroxide at 70 – 75 8C and with boron trifluoride at 1 – 4 8C). The polymer was precipitated from methanol and dried in a vacuum oven. The polymerization results are resumed in the following in Table 12. The low yields arose from the polar and the steric effect of TFS which decrease the reactivity of the double bond. Prober [45] also reported that the emulsion copolymerization of a,b,b-trifluorostyrene with styrene was initiated by potassium persulfate at 50 8C in sealed tubes for 72 h using emulsifiers like ‘Ivory Soap’ (sodium tetraborate decahydrate, 67% conversion), Aerosol OT (47% conversion), Dodecylamine hydrochloride (83% conversion). Softening points of the polymers were ranging between 207 and 225 8C. In 1981, Tevlina et al. [97] copolymerized a,b,b-trifluorostyrene (I) with vinyl fluoro monomers like N-vinylpyrrolidone (II), H2CyCF –CN (III), FHCyCF –COOMe (IV) and F2CyC(CF3)COOMe in the presence of AIBN. The low reactivity of (I) was related to the presence of fluorine in both b-position of the vinyl group. The high polarity of bonds in compounds III, IV and V was related to the electron acceptor effect of fluorine. Compounds II, III and IV were highly reactive in copolymerization with I. The copolymers could be used in the production of homogeneous cation exchange membranes with good physico-chemical properties. The p-chloro or fluorosulfonate-a,b,b-trifluorostyrene synthesized by Stone et al. [93] was copolymerized with trifluorostyrene functionalized or not. The emulsion copolymerization occurred with dodecylamine hydrochloride (Scheme 26). The physico-chemical properties (Tg ; Td ) and details such as molecular weight or polydispersity index of copolymers were not reported. Nevertheless,

Scheme 23. Synthesis of a,b,b-trifluorostyrene by Heinze and Burton [47].

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106 Table 11 Yields of synthesis of a series of substitued a,b,b-trifluorostyrenes according to Heinze and Burton [47] R

Solvent

Yields (%)

– o-NO2 p-MeO o-(CH3)2CH 2,5-Cl2 o-CF3 m-NO2 p-Cl p-CF2yCF

DMF DMF THF THF DMF TG TG DMF DMF

74 73 31 70 75 73 81 77 56

TG: triglyme.

the materials prepared with such polymers have fuel cell applications. In 1999, Stone et al. [98] prepared an ion-containing polymers based on phosphonic acid trifluorostyrene. The synthesis was based on two basic steps. The first one dealt with the synthesis of 4-iodobenzene phosphonic acid dimethyl ester, while the second one concerned the synthesis of the p-dimethyl phosphonate-a,b,b-trifluorostyrene. The 4-iodobenzene phosphonic acid dimethyl ester (27-1) was prepared as described in Scheme 27 and reacted with trifluoroethenylzinc bromide reagent ((27-2), Scheme 27) in the presence of a palladium(0) catalyst [47] to produce

89

the desired dimethylphosphonate-substituted-a,b,btrifluorostyrene monomer ((27-3), Scheme 27). These authors reached two main goals. The first goal of the authors was to prepare an homopolymer ((27-4), Scheme 27) of monomer (27-3) and thereby achieved the highest degree of ionization and lowest equivalent weight for an ionomer of this structure. Stone et al. [98] attempted to synthesize the homopolymer of (27-3) (Scheme 27) using a variety of standard techniques including emulsion polymerization, solution polymerization (in toluene), and bulk polymerization. The highest yield (34%) resulted from bulk polymerization initiated by AIBN. In all cases, the isolated material was analyzed and resulted a multi-modal GPC traces (Mn ; Mw ; Ip and Tg were not detailed) and 1H NMR spectra indicating that mixtures of oligomeric and polymeric materials were produced. According to the authors, the prepared material (cast as a dense film) was evidenced by a low intrinsic viscosity and very poor mechanical properties. Nevertheless, the homopolymer (27-4) was hydrolyzed to afford an ionomer mixture, which was soluble in aqueous base. As a consequence, the physical properties of ionomer ((27-4), Scheme 27) did not fulfill the requirements for use these polymers as a PEM in a fuel cell. The second goal of the authors was to copolymerize monomer (27-3) with a,b,b-trifluorostyrene (TFS)

Scheme 24. Cyclodimerization of a,b,b-trifluorostyrene [89–91].

Scheme 25. Synthesis of 4-fluorosulfonate-a,b,b-trifluorostyrene [93].

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Table 12 Polymerization yields of a,b,b-trifluorostyrene [45] Initiator

Temperature (8C)

Polymerization yields (%)

Benzoyl peroxide Bisazoisobutyronitrile t-Butyl hydroperoxide t-Butyl perbenzoate Di-t-butyl peroxide

65–68 45–50 81–83 101–104 120–123

6.2 4.0 4.3 0.7 6.4

(Scheme 28). It was achieved by emulsion polymerization in a process that afforded a rather modest isolated yield of 21%. The optimized ratio between TFS and dimethylphosphonate-substituted-a,b,b-trifluorostyrene monomer in the copolymer (28-1) (Scheme 28) was 2.4:1. The GPC analysis and intrinsic viscosity measurements indicated that the copolymer showed a higher molecular weight copolymer (Mn ¼ 38; 100 g/mol and Mw ¼ 105; 900 g/mol) than of the homopolymer of (27-4) (Scheme 27). The isolated material has a narrow polydispersity index ðIp ¼ 2:8Þ:

The last goal of the authors was to hydrolyze homopolymer (27-4) and the copolymer of TFS with dimethylphosphonate-4-substituted-a,b,b-trifluorostyrene (28-1). Different ways were used. For each cases, two possibilities of hydrolysis were achieved. The two processes for hydrolysis of the homopolymer (27-4) were the following: (1) The first one was an acid hydrolysis in hydrochloric acid in dioxane (100 8C, 20 h) [99]. The yield and the equivalent weight of acid functions were 87% and 130 g/mol, respectively. (2) The membrane (A) based on the homopolymer (27-4), was directly hydrolyzed in the presence of hydrochloric acid. The yield and the equivalent weight of acid functions were 95% and 130 g/mol, respectively. The two proceeds for hydrolysis of the copolymer TFS with dimethylphosphonate-substituted-a,b, b-trifluorostyrene monomer (28-1) were:

Scheme 26. Copolymerization of fluorosulfonate-a,b,b-trifluorostyrene [93].

Scheme 27. Synthesis and homopolymerization of dimethylphosphonate-4-substituted-a,b,b-trifluorostyrene according to Stone et al. [98].

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106

91

Scheme 28. Hydrolysis of the copolymer of TFS with dimethylphosphonate-4-substituted-a,b,b-trifluorostyrene according to Stone et al. [98].

(1) The first one concerned a basic hydrolysis in the presence of potassium hydroxide (84 8C, 64 h). The yield and the equivalent weight of acid functions were 87% and 350 g/mol, respectively. The authors could prepare a membrane with this hydrolyzed copolymer (called C1). (2) The second hydrolysis occurred in acid conditions, but the copolymer was pre-treated in DMF solution. The yield and the equivalent weight of acid functions were 66% and

210 g/mol, respectively. The membrane prepared from this hydrolyzed copolymer was called C3. Membranes like C1 and C3 are useful as original protonic membranes and three main teams [98,100, 101] have investigated their proton conductivities and their swelling rate in water. The electrochemical characteristics are presented in Table 13. The authors concluded [98] that the best results were obtained with an acid hydrolysis and at last,

Table 13 Electrochemical characteristics of different ionomer membranes (Stone et al. [98], Xu and Cabasso [100], and Kotov et al. [101]) Ionomer

EW (g/mol)

EW effective (g/mol)

Transverse proton conductivity (S/cm £ 102)

Water absorption at 100 8C (%)

Reference

A (membrane based on homopolymer 27-4) C1 (membrane based on copolymer 28-2) C3 (membrane based on copolymer 28-2) D (membrane based on 3.86:1 ratio n : m [CF2 –CF2]n[CF2 –CFX]m with X ¼ O(CF2)3P(O)(OH)2) E (membrane based on 4.63:1 ratio n : m [CF2 –CF2]n[CF2 –CFX]m with X ¼ O(CF2)3P(O)(OH)2) F (membrane based on poly(dimethylphenylene oxide phosphonic acid)) G (membrane based on poly(dimethylphenylene oxide diphosphonic acid))

130 350 200 357

215 670 380 357

– 0.01–0.001 – 7.6

– 15 77 22

[98] [98] [98] [101]

370

370

6.9

21

[101]

111

202

–

–

[100]

70

107

–

–

[100]

EW: equivalent weight.

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5. Synthesis and (co)polymerization of [(a,b,btrifluorovinyl)oxy] benzene

Fig. 4. [(a,b,b-trifluorovinyl)oxy]benzene monomer.

they explained that the membrane based on a sulfonic acid-a,b,b-trifluorostyrene gave better results that those obtained from phosphonic acid homologue.

4.2. Conclusion a,b,b-trifluorostyrene is very interesting monomer which can cyclodimerize. Its synthesis can be achieved using different synthetic ways like the coupling route between functional aryl iodides and perfluoroalkenylzinc reagent. Interestingly, this monomer was functionalized by acid group such as chlorosulfonic or phosphonic acid for proton exchange membrane applications. However, one of the main drawback of this monomer is its difficult homopolymerization, except in emulsion [45,89] or plasma [102] processes. Nevertheless, the copolymerization of acid functional a,b,b-trifluorostyrene was achieved by Stone et al. [98] and lead to material having high molecular weights and good proton exchange properties. Hence more researchers have been devoted to prepare aromatic monomers that exhibit a trifluorovinyl group and one of the issue was to introduce an ether bridge between that F2CyCF – group and the aromatic ring.

Various route of dealing with the synthesis and the polymerization of [(a,b,b-trifluorovinyl)oxy] benzene or [(a,b,b-trifluoroethenyl)oxy] benzene (Fig. 4) have been investigated and are presented here after. Because of the combination of processability and performance provided by trifluorovinyl ethers and polymers incorporating such a monomer, [(a,b,btrifluorovinyl)oxy] benzene have received attention by various research groups [103 – 107] and are relevant materials for the preparation of ion exchange resins [108,109], ionomer membrane [110], microphonic [111], optic [112 – 115], liquid crystalline [116 –118], interlayer dielectrics [119,120], circuit board laminates [121], and coating applications [122, 123]. They were obtained for the first time by Beckerbauer in 1968 [124] who was the first author to show that perfluoroalkyl trifluorovinyl ethers could undergo thermal cyclopolymerization giving low molecular weight perfluoroalkylpolymers. The synthesis of trifluorovinyl ethers and their applications have also been patented by different industries such as the Dow Chemical company in the 1990s [125,126], Merck [127], in 1995, 3M in 2001 [109]. One of the most important features of aryl a,b,btrifluorovinyl ether is to thermocyclodimerize [2p þ 2p] (Scheme 29). A thermoplastic and thermoset perfluorocyclobutane (PFCB) were also formed [106,128 – 132]. The aryl a,b,b-trifluorovinyl ether [2p þ 2p] thermocyclodimerization is favored thermodynamically

Scheme 29. Formation of aromatic perfluorocyclobutane (PFCB) [106,128– 132].

Scheme 30. Aromatic trifluorovinyl ethers [130,136].

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Scheme 31. Synthesis of monomer (30-1) [130,136].

and due to an increase of the double bond strain [133], a lower CyC p-bond energy [134], and the strength of the resulting fluorinated C–C single bond. For trifluorovinyl ether (TFVE) monomers, exothermal polymerization reached a measurable rate (DSC at 10 8C/min) near 140 8C and polymerizations were typically carried out at temperature between 150 and 210 8C [135]. 5.1. Preparation method and (co)polymerization of [(a,b,b-trifluorovinyl)oxy] benzene In 1993, Babb et al. [130,136] developed synthetic routes for the synthesis and the characterization of

trifluorovinyl ethers (compounds (30-1) and (30-2), Scheme 30) prepared readily available from bis and trisphenols, such as, tris(hydroxyphenyl)ethane (for (30-1)) and biphenol (for (30-2)). For example, Scheme 31 describes the synthesis of trifluorovinylethers prepared from tris(hydroxyphenyl) ethane. The low observed yields for the non-dehalogenated synthon could be explained by the steric hindrance and also the presence of by product such as the mono and the dibrominated compound. According to the authors, monomers (30-1) and (30-2) provide high-Tg thermoset polymers (18 8C)

Scheme 32. Synthesis of bis[1,3-[4-[(trifluorovinyl)oxy]phenyl]]-1,1,3,3-tetramethyldisiloxane according to Smith and Babb [106].

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Scheme 33. Cyclopolymerization of bis[1,3-[4-[(trifluorovinyl)oxy]phenyl]]-1,1,3,3-tetramethyldisiloxane [106]. Table 14 Molecular weights and thermal characteristics of polymer of bis[1,3-[4-[(trifluorovinyl)oxy]phenyl]]-1,1,3,3-tetramethyldisiloxane (33-1) [106] GPC (Mn )

19 F NMR (Mn )

Mw

Mw =Mn

Tg (8C)—DSC

Td (8C)/N2

10,000

13,000

34,000

3.4

16

428

with good thermal stability (they are stable up to 434 8C), thermal/oxidative stability and mechanical properties [123,131]. In 1996, Smith and Babb [106] developed different new synthetic routes to synthesize perfluorocyclobutane aromatic polyethers with a siloxane

group. Fluorinated siloxane polymers are currently employed commercially as high-temperature lubricants, elastomers, and adhesives with excellent chemical, thermal, and oxidative resistance [137]. They synthesized one of them with the aryl Grignard reagent from 4-[(trifluorovinyl)oxy)]bromobenzene ((32-3), Scheme 32) allowed for the high-yield (87%) synthesis of 4-[(trifluorovinyl)oxy]phenyldimethylsilane which was at last dehydrogenatively hydrolyzed in situ and condensed to yield bis[1,3-[4[(trifluorovinyl)oxy]phenyl]]-1,1,3,3-tetramethyldisiloxane ((32-6), Scheme 32) with a 43% yield (Scheme 32). Authors also thermocyclopolymerized such monomer. The homopolymerization of (32-6) to siloxane perfluorocyclobutane ((33-1), Scheme 33) was achieved by heating the monomer at 210 8C for 14 h as follows. The cyclopolymerization is thermally initiated without any catalyst, such that polymerization was stopped upon the removal of heat, leaving quantifiable end group intact. Table 14 contains different physical data. In 2000, Smith et al. [123] reported the synthesis of different perfluorocyclobutane (PFCB) polyarylethers (Scheme 34). As explained in former communications [138,139], the different triflurorovinyl ethers were prepared in two steps: the first one concerned a fluoroalkylation

Scheme 34. Polyarylvinyl ether synthesized by Smith et al. [123].

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106 Table 15 Mechanical and physico-chemical properties of polymer (34-1) [138] Selected properties

Values

Tensile strength (MPa) Tensile modulus (MPa) Flexural strength (MPa) Flexural modulus (MPa) %Elongation (break) Tg (DMA) Dielectric constant (10 kHz) Dissipation factor (10 kHz) %Water absorption (24 h) Refractive index (800 nm)

66.0 ^ 1.4 2.270 ^ 79 74 ^ 12 2.320 ^ 13 4.1 380 8C 2.35 0.0004 0.021 1.495

Scheme 35. Grignard agent [140] and lithium [141–143] of 4[(trifluorovinyl)oxy)]bromobenzene.

with BrCF2CF2Br while the second one deals with a zinc mediated elimination. For the authors, the thermal and thermal oxidative stability, mechanical properties of PFCB polymers are very good [131]. Table 15 gives the physico-chemical properties of PFCB thermoset polymer prepared from monomer (34-1) [138] (Scheme 34). 4-[(Trifluorovinyl)oxy)]bromobenzene ((32-3), Scheme 35) can be converted to a reactive Grignard (M:Mg, Scheme 35) [140] or Lithium (M: Li, Scheme 35) compound [141 –143] and gained access to an increasing number of organic/inorganic fluorinated compounds [106,144]. For example, in 1998, Xu et al. [140] described in a first part the synthesis of 3-(4-trifluorovinyloxy phenyl) thiophene ((36-1), Scheme 36) using

95

the Grignard agent from 4-[(a,b,b-trifluorovinyl) oxy]bromobenzene which was coupled with 3bromo thiophene. Such a reaction was catalyzed by nickel(II) chloride (Scheme 36). This monomer was characterized by a frequency at 1834 cm21 in FTIR and an exothermic peak at 181 8C and a maximum exotherm at 235 8C in DSC (10 8C/min). In a second part, the same authors cyclothermodimerized 3-(4-trifluorovinyloxy phenyl) thiophene at 230 8C for 12 h. Materials prepared from such dimers ((37-1), Scheme 37) gave stable, reversible polymer films which showed good p- and n-doping characteristics. For a second example, Babb et al. [145] reported the preparation of a novel triaryl phosphine oxide thermoset polymer containing a perfluorocyclobutane linkage ((38-4), Scheme 38). The synthetic route is similar to that of the former example, using a Grignard reagent from the 4-[(trifluorovinyl)oxy]bromobenzene ((32-3), Scheme 38), which was condensed on a phosphorous trichloride. The oxidative form ((38-3), Scheme 38) of the phosphine ((38-2), Scheme 38) was obtained by oxidation with hydrogen peroxide in alcohol. The monomer ((38-3), Scheme 38) was prepared in 77% yield. The bulk polymerization of monomer (38-3) was characterized by an enthalpy ðDHÞ equal to 2 55 kcal/mol and the polymer obtained showed good thermal properties. Its thermal decomposition data (38-4) are summarized in Table 16. In a third example, Boone et al. [139] reported the synthesis and the thermal characterization of 1,3,5tris[(4-trifluorovinyloxy)phenyl]benzene (monomer (39-2), Scheme 39). These authors first synthesized the Grignard reagent of monomer ((32-3), Scheme 39) that was condensed with a trimethylborate, then hydrolyzed to the corresponding acid ((39-1), Scheme 39). Finally, synthon (39-1) was crosscoupled with 1,3,5-tribromobenzene using a tetrakis

Scheme 36. Synthesis of 3-(4-trifluorovinyloxy phenyl)thiophene according to Xu et al. [140].

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Scheme 37. Cyclothermodimerization of 3-(4-trifluorovinyloxy phenyl)thiophene [140].

(triphenylphosphine)-palladium as the catalyst [146]. Monomer (39-2) was obtained with a 41% overall yield. Thermoset polymer (39-3) obtained by cyclothermodimerization of (39-2) had a Tg of 345 8C. Polymer (39-3) and polyphosphine oxide PFCB ((38-4), Scheme 38) have similar rates of degradation at temperatures below 375 8C (Table 17). Table 17 summarized the isothermal degradation kinetics data for polymer (39-3). For a fourth example, Rizzo and Harris [147] described the synthesis and thermal properties of fluorosilicones-containing perfluorocyclobutane rings such as 1,2-bis[4-(dimethylhydroxysilyl)phenoxy]-1,2,3,3,4,4-hexafluorocyclobutane (40-3) and

1,2-bis[3-(dimethylhydroxysilyl)phenoxy]1,2,3,3, 4,4-hexafluorocyclobutane (41-6). The synthetic routes of both monomers are described in Schemes 40 and 41. The synthetic route of synthon (32-3) (Scheme 40) and (41-3) (Scheme 41), is based on former works of Smith and Babb [106]. Intermediates (401) and (41-4) were obtained via a cross-coupling reaction between a Grignard reagent of compound (32-3) and (41-3) and SiH(CH3)Cl. The thermocyclodimerization of each monomer was realized at 150 8C. Dimers VI and XII were self-polymerized by treatment with bases such as KOH or NaH, and their glass transition temperatures were 27 and 2 12 8C, respectively. Authors also reported the copolymerization of (40-3) and (41-6) with a,vsilanol-terminated 3,3,3-trifluoropropylmethylsiloxane oligomer to form copolymers with varying compositions (the copolymer compositions, thermal properties and the swelling behavior are described in the publication). In 1998, Narayan-Sarathy et al. [141,142] reported the preparation and the synthetic utility of [ p-((trifluorovinyl)oxy)phenyl]lithium ((42-1), Scheme 42) which was obtained by a metal – halogen exchange reaction of 4-[(trifluorovinyl)oxy]bromobenzene ((32-3), Scheme 42) with

Scheme 38. Triaryl phosphine oxide thermoset polymer containing a perfluorocyclobutane [145].

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106 Table 16 Thermal decomposition data for polymer (38-4) under nitrogen and under air (k stands for isothermal degradation kinetic constant) [145] Nitrogen

Air

T (8C)

1=T (1000/K)

k (%/h)

ln k (%/h)

T (8C)

1=T (1000/K)

k (%/h)

ln k (%/h)

422 396 374 348 318

1.439 1.468 1.546 1.610 1.692

48.00 10.80 1.62 0.30 0.04

3.871 2.380 0.482 2 1.204 2 3.124

423 398 373 348 318

1.437 1.490 1.548 1.610 1.692

49.00 12.00 2.72 0.68 0.12

3.892 2.485 1.001 2 0.393 2 2.120

Ea=R ¼ 27.626, Ea ¼ 54:900 kcal/mol.

terbutyllithium in ether at 2 78 8C. According to the authors [148], Grignard reagent from monomer (32-3) was not reactive enough toward many electrophiles.

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The authors also showed the remarkable formation and stability of anion ((42-1), Scheme 42). They concluded that the trifluorovinyl group in the 4[(trifluorovinyl)oxy]bromobenzene delocalizes charges very well and also clearly illustrates the decreased electrophilicity of the olefin and hence the decreased susceptibility to nucleophilic attack. With compounds (42-1) (Scheme 42), authors prepared a wide range of different types of inorganic/organic compounds [141] using chlorosilanes such as Me 2Si(Cl)CHyCH 2 , MeSiCl 3, (Me3Si)2 NPBr2 and CH3COOMe (Scheme 43). Yields and boiling points of each compound are reported in Table 18. In 2000, Ford et al. [143] reported the synthesis of aromatic perfluorovinyl ether monomers containing the sulfonamide and the sulfonic acid functionality for different applications such as the preparation

Scheme 39. Synthesis of 1,3,5-tris[(4-trifluorovinyloxy)phenyl]benzene according to Boone et al. [139]. Table 17 Thermal decomposition data for polymer (39-3) under nitrogen and under air (k stands for isothermal degradation kinetic constant) [139] Nitrogen

Air

T (8C)

1=T (1000/K)

k (%/h)

ln k (%/h)

T (8C)

1=T (1000/K)

k (%/h)

ln k (%/h)

434 407 382 358 324

1.414 1.471 1.527 1.585 1.675

27.6 4.83 0.99 0.288 0.024

3.318 1.575 20.010 21.245 23.730

426 406 375 351 324

1.431 1.473 1.543 1.603 1.675

28 6.96 2 0.675 0.18

3.332 1.940 0.693 20.393 21.715

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Scheme 40. Synthesis of 1,2-bis[4-(dimethylhydroxysilyl)phenoxy]-1,2,3,3,4,4-hexafluorocyclobutane [147].

Scheme 41. Synthesis of 1,2-bis[3-(dimethylhydroxysilyl)phenoxy]1,2,3,3,4,4-hexafluorocyclobutane [147].

of Proton Exchange Membrane Fuel Cell [149 – 152]. As the former example, Ford et al. used a [ p-((trifluorovinyl)oxy)phenyl]lithium which was cross-coupling with FSO2Cl to give 4-[(trifluorovinyl)oxy]benzenesulfonyl chloride in a 65% yield ((44-1), Scheme 44). Monomers (44-2), (44-3) and (44-4) were prepared in 91, 85 and 80% yield, respectively. The thermal behavior of monomer (48-3) has been investigated by a series of heating/cooling in DSC. The exothermic polymerization begins at 175 8C ðTonset Þ and 214 8C ðTmax Þ: Different monomers which have similar structure as that of monomer (44-1) (Scheme 44) were patented by 3M Innovative Properties Company [109] in 2001 (Scheme 45). In addition, aromatic perfluorovinyl ether monomers containing chromophores [115], heterocycles

[153] and macrocyclic ligands [154] have been synthesized for optic applications. More recently, in 2002, Souzy et al. [155] studied the radical homo-, co-, and terpolymerization of 4-[(a,b,b-trifluorovinyl)oxy]bromobenzene with commercially available fluoroalkenes such as vinylidene fluoride (VDF) and/or chlorotrifluoroethylene (CTFE), and/or hexafluoropropene (HFP), and/or perfluorovinyl methyl ether (PMVE). As mentioned above, a,b,b-trifluorovinyl benzyl ethers are interesting monomers because they can lead to thermostable

Scheme 42. Synthesis of [ p-((trifluorovinyl)oxy)phenyl]lithium [141,142].

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99

Scheme 43. Synthesis of different polyarylene vinyl ether using [ p-((a,b,b-trifluorovinyl)oxy)phenyl]lithium [141].

fluoropolymers. Surprisingly, before 2002, no (co) and or terpolymerizations, under radical conditions, of these [(a,b,b-trifluorovinyl)oxy]benzene with the radical co- and terpolymerization of a,b,b-trifluorovinyl benzyl ethers with VDF/HFP and VDF/CTFE was achieved. These authors first prepared and characterized 4[(a,b,b-trifluorovinyl)oxy]bromobenzene ((32-3), Scheme 32) according to Smith and Babb’s procedure [106] on similar yields. Then, the authors, functionalized monomer (32-3) [156] with a diethoxy or dimethoxy phosphonate group ((46-1), Scheme 46) using lithium agent of [(a,b,b-trifluorovinyl)oxy]benzene [141 – 143] (Scheme 35) and dimethyl chlorophosphate or hydrogenodiethylphosphite via the reaction carried out by Heinicke et al. [157]. Other alternatives involving triethyl or trimethylphosphite as reactants were also attempted in the condition of Tavs reaction [158]. This original v-phosphonate monomer and its copolymers with fluoroalkenes were characterized by 1 H, 19F and 31P NMR, and thus, the authors could assess the content phosphorous-containing monomer and those of fluoroalkenes. In a second time, Souzy et al. [155,159] extensively studied the radical homo-, co-, ter-, and tetrapolymerization of 4-[(a,b,b-trifluorovinyl)oxy]bromobenzene with VDF, HFP, CTFE and PMVE. A wide range of experiments were carried out to propose a polymerization model of monomer (32-3). They first conclude

that fluoroaromatic monomer (32-3) did not homopolymerize under radical conditions but thermocyclodimerized hence confirming Smith and Babb’s results [142]. However, the authors [155,159] concluded that 4-[(a,b,b-trifluorovinyl)oxy]bromobenzene could copolymerize with VDF and CTFE only. This low reactivity could be explained by the electronic effect of the aromatic ring. Nevertheless, the final molar percentage of the monomer was not high (up to 6%). Finally, new experiments were also investigated by the authors and were based on the radical terpolymerization of (32-3) with VDF/HFP, VDF/PMVE, and VDF/ CTFE. The best incorporation rates and yields were observed in experiments involving VDF/HFP and VDF/PMVE blends (up to 18.6 mol%). 5.2. Conclusion [(a,b,b-trifluorovinyl)oxy]benzene are very interesting monomers which are currently used for the preparation of ion exchange resins [108] and ionomer Table 18 Yields of synthesis and their boiling points [141] Compounds

Yields (%)

Boiling point

43-1 43-2 43-3 43-4

78 58 73 62

78 8C/3 mm Hg 110 8C/0.07 mm Hg 103 –113 8C/0.01 mm Hg 90 –108 8C/0.01 mm Hg

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Scheme 44. Synthesis of aromatic perfluorovinyl ether monomers containing the sulfonamide and the sulfonic acid functionality according to Ford et al. [143].

membrane [110]. This monomers could undergo thermal cyclopolymerization giving low molecular weight perfluoroalkylpolymers and provide high-Tg thermoset polymers with good thermal stability. Most of the functional organic/inorganic monomers incorporating a trifluorovinyl ether group are obtained by a coupling reaction between a reactive Grignard or lithium agent functionalized by a trifluorovinyloxy function and various electrophilic compounds. Recent investigations dealing with those of these aromatic fluoromonomers with VDF, CTFE, HFP and PMVE led to encouraging results. The higher the fluoroaromatic monomers in the feed, the lower the yields; this behavior in copolymerization probably being assigned to the aromatic ring that may trap radical. Nevertheless, these above copolymerization seemed to be more encouraging that these involving a,b,btrifluorostyrene.

fluorinated aromatic polymers represent a new and interesting generation. This review has shown that many ways are possible to achieve the preparation of various kinds of fluoromonomers: the mono, di and trifluorostyrene monomers and their (co)polymerizations have also been studied. First, the synthesis of monofluorostyrene as a- and b-fluorostyrene involves dehydrofluorination of fluoroethylbenzene, or coupling reaction between an aryl iodide and VDF, or a Wittig reaction using ketones and triphenylphosphine. However, the (co)polymerization of a-fluorostyrene leads to different molecular weight polymers, obtained by bulk radical, or cationic techniques, or emulsion under buffered neutral or

6. Conclusion Fluorinated polymers have a unique combination of high performance properties and can be used, despite their high price, in high performance application such as aerospace, aeronautics, microelectronics, and coatings. Among fluoropolymers,

Scheme 45. Functionalized polyarylene vinyl ethers according to 3M Innovative Properties company [109].

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101

Scheme 46. Synthesis of 4-di-alkyl-oxyphosphonate-[(a,b,b-trifluorovinyl)oxy] benzene [155,156].

alkaline conditions polymerization. However, poly(afluorostyrene) undergo deshydrofluorination. As a matter of fact, the copolymerization of b- and functional b-fluorostyrene has not been investigated. The second part of this review has dealt with the synthesis and the (co)polymerization of difluorostyrene. Hence, tremendous works carried out by Burton’s team were successful in the cross-coupling reaction between zinc reagent such as (E) or (Z) XYCyCW – ZnT (X, Y, W: H, CF3 or F and T: Br or I), and functional aryl iodides in presence of palladium catalyst seems to be the best way to synthesize a,bor b,b-difluorostyrenes. However, the polymerization of a,b-difluorostyrene leads to materials having nonexpected properties since their molecular weights were low and their thermal properties poor. Moreover, the copolymerization of functional b,b-difluorostyrene like 2-benzoyloxypentafluoropropene with vinylidene fluoride were encouraging. Interestingly, a,b,b-trifluorostyrene (TFS) and especially aromatic trifluorovinyl ethers are relevant monomers which can cyclodimerize. Their synthesis can be achieved using different synthetic routes by coupling functional aryl iodides and perfluoroalkenylzinc reagent for a,b,b-trifluorostyrene and addition of functionalized phenate and 1,2dibromo-tetrafluoroethane (BrCF2CF2Br) followed by a dehalogenation step for obtaining aromatic trifluorovinyl ethers. TFS can homopolymerize and copolymerize under emulsion process. It is worth mentioning that aromatic trifluorovinyl ethers undergo thermal cyclopolymerization giving

material characterized by good physical properties. Nevertheless, the (co) and terpolymerization of TFS and aromatic trifluorovinyl ethers with fluoroolefins such as vinylidene fluoride, hexafluoropropene, perfluoromethylvinyl ether or chlorotrifluoroethylene are still investigated and could lead to very interesting materials having wave guides or proton exchange properties. Hence, the acidity of the monomers incorporated is enhanced by the presence of the aromatic groups. Such new promising proton exchange membrane or wave guides materials are nowadays real challenges for fuel cell applications and for the optic industry, and should attract the interest of many academic and industrial researchers.

Acknowledgements The authors acknowledge the Centre National de la Recherche Scientifique, GOR 2479 PACEM, and the Commissariat a` l’Energie Atomique for the financial support of the PhD studies (to R.S.).

References [1] Wall LA. Fluoropolymers. New York: Wiley; 1972. [2] Carlson DP, Schmiegel WW, Ullmann’s encyclopedia of industrial chemistry, vol. A11. New York: VCH Publishers; 1988. p. 393. [3] Gangal SV, Encyclopedia of polymer science and engineering, vol. 16. New York: Wiley; 1989. p. 577 –600.

102

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106

[4] Labadie JW, Hedrick JL. Perfluoroalkylene-activated poly(aryl ether) synthesis. Macromolecules 1990;23(26): 5371–3. [5] Yamabe M. A challenge to novel fluoropolymers. Makromol Chem Macromol Symp 1992;64:11– 18. [6] Mercer F, Goodman T, Wojtowicz J, Duff D. Synthesis and characterization of fluorinated aryl ethers prepared from decafluorobiphenyl. J Polym Sci, Part A: Polym Chem 1992; 30(8):1767– 70. [7] Mercer F, Duff D, Wojtowicz J, Goodman T. Low dielectric constant of fluorinated aryl ethers prepared from decafluorobiphenyl. Polym Mater Sci Engng (Am Chem Soc, Div PMSE) 1992;66:198– 9. [8] Feiring AE. Fluropolymers. In: Banks RE, Smart B, Tatlow TC, editors. Organofluorine chemistry principles and commercial applications, vol. 15.; 1994. p. 339. [9] Feiring AEJ. Synthesis of new fluoropolymers: tailoring macromolecular properties with fluorinated substituents. Macromol Sci, Pure Appl Chem 1994;A31(11):1657–73. [10] Feiring AEJ, Imalzano JF, Kerbow DL. Developments in commercial fluoroplastics. Trends Polym Sci 1994;2(1): 26–30. [11] Smart BE. Properties of fluorinated compounds, physical and physicochemical properties. In: Hudlicky M, Pavlath SE, editors. Chemistry of organic fluorine compounds II. ACS Monograph 187, Washington, DC: American Chemical Society; 1995. p. 979. [12] Scheirs J. Modern fluoropolymers. Victoria, Australia: Wiley; 1997. [13] Hougham G, Johns K, Cassidy PE, Davidson T. Fluoropolymers: synthesis and polymerization, Vol 1 and 2. New York: Plenum Press; 1999. [14] Ameduri B, Boutevin B, Kostov G. Fluoroelastomers: synthesis, properties and applications. Prog Polym Sci 2001;26(1):105 –87. [15] Qiu J, Matyjaszewski K. Polymerization of substituted styrenes by atom transfer radical polymerization. Macromolecules 1997;30:5643– 8. [16] Becker M, Wooley KL. Radical-based preparation of block copolymers containing fluorine tags: tools for detailed analysis of nanostructured materials. Polym Prepr (Am Chem Soc, Div Polym Chem 2000;41(2):1328–9. [17] Becker ML, Remsen EE, Wooley KL. Diblock copolymers, micelles, and shell-crosslinked nanoparticles containing poly(4-fluorostyrene): tools for detailed analyses of nanostructured materials. J Polym Sci, Part A, Polym Chem 2001; 39(23):4152– 66. [18] Lacroix-Desmazes P, Boutevin B, Taylor DK, DeSimone JM. Synthesis of fluorinated block copolymers by nitroxidemediated radical polymerization for supercritical carbon dioxide applications. Polym Prepr (Am Chem Soc, Div Polym Chem) 2002;43(2):285 –6. [19] Gali J, Anduzzi L, Ober C. Fluorine in Coating V Conference, Orlando, USA, 21 –22 January. 2003. paper #4. [20] Nishimura S, Nagai A, Takahashi A, Narita T, Hagiwara T, Hamana H. Anionic polymerization of 2,3,4,5,6-pentafluorostyrene. Polym J 1990;22(2):171–4.

[21] Han LM, Timmons RB, Lee WW, Chen Y, Hu Z. Pulsed plasma polymerization of pentafluorostyrene: synthesis of low dielectric constant films. J Appl Phys 1998;84(1): 439 –44. [22] Kurosawa S, Hirokawa T, Kashima K, Aizawa H, Han DS, Yoshimi Y, Okada Y, Yase K, Miyake J, Yoshimoto M, Hilborn J. Detection of deposition rate of plasma-polymerized films by quartz crystal microbalance. Thin Solid Films 2000;374(2):262 –7. [23] Pryor WA, Huang TL. Reactions of radicals. XVIII. Kinetics of the polymerization of pentafluorostyrene. Macromolecules 1969;2(1):70– 7. [24] Hvilsted S, Borkar S, Abildgard L, Georgieva V, Siesler HW, Jankova K. Polymers and block copolymers of fluorostyrenes by ATRP. Polym Prepr (Am Chem Soc, Div Polym Chem) 2002;43(2):26– 7. [25] Jankova K, Hvilsted S. Preparation of poly(2,3,4,5,6pentafluorostyrene) and block copolymers with styrene by ATRP. Macromolecules 2003;36(5):1753 –8. [26] Bartlett B, Buckley LJ, Godbey DJ, Schroeder MJ, Fontenot C, Eisinger S. Vapor deposition polymerization of 4fluorostyrene and pentafluorostyrene. J Vac Sci Technol 1999;17(1):90– 4. [27] Pitois C, Vukmirovic S, Hult A, Wiesmann D, Robertsson M. Low-loss passive optical waveguides based on photosensitive poly(pentafluorostyrene-co-glycidyl methacrylate). Macromolecules 1999;32(9):2903–9. [28] Cohen SG, Wolosinski HT, Scheuer PJ. a,b,b-Trifluorostyrene and a-chloro-b,b-difluorostyrene. J Am Chem Soc 1949; 71:3439–40. [29] Reynolds DW, Cassidy PE, Johnson CG, Cameron ML. Exploring the chemistry of the 2-arylhexafluoro-2-propanol group: synthesis and reactions of a new highly fluorinated monomer intermediate and its derivatives. J Org Chem 1990; 55(14):4448–54. [30] Middleton WJ, Bingham EM. The synthesis of antiinflammatory a-(trifluoromethyl)arylacetic acids. J Fluorine Chem 1983;22(6):561 –74. [31] Middleton WJ, Metzger D, Snyder JA. 1-Trifluoromethyl-1, 2,2-triphenylethylenes. Synthesis and postcoital antifertility activity. J Med Chem 1971;14(12):1193–7. [32] Matsuda K, Noland JS, Sedlak JA, Gleckler GC. aFluorostyrene: preparation, properties, and polymerization. J Org Chem 1962;27:4015–20. [33] Heitz W, Knebelkamp A. Synthesis of fluorostyrenes via palladium-catalyzed reactions of aromatic halides with fluoroolefins. Makromol Chem, Rapid commun 1991;12(2): 69 –75. [34] Heitz W, Knebelkamp A. Synthesis and properties of poly(afluorostyrenes). Polym Prepr (Am Chem Soc, Div Polym Chem) 1991;32(1):383–4. [35] Knebelkamp A, Heitz W. Synthesis and properties of poly(afluorostyrenes). Makromol Chem, Rapid Commun 1991; 12(10):597–606. [36] Heck RF. Palladium-triarylphosphine complexes as catalysts for vinylic halide reactions. Adv Chem Ser 1982;196: 213 –30.

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106 [37] Meyer OGJ, Fro¨hlich R, Haufe G. Asymmetric cyclopropanation of vinyl fluorides: access to enantiopure monofluorinated cyclopropane carboxylates. Synthesis 2000;10: 1479–90. [38] Eckes L, Hanack M. Preparation of vinyl fluorides. Synthesis 1978;3:217– 9. [39] Alvernhe G, Laurent A, Haufe G. Triethylamine tris(hydrofluoride) [(C2H5)3N·3HF]: a highly versatile source of fluoride ion for the halofluorination of alkenes. Synthesis 1987;6:562– 4. [40] Liu HW, Walsh CT. Biochemistry of the cyclopropyl group. In: The Chemistry of the cyclopropyl group, New York: Wiley; 1987. p. 959–1025. [41] Bogachev AA, Kobrina LS, Meyer OGJ, Haufe G. Diels – Alder reactions of polyfluorinated 2,4-cyclohexadienones with a- and b-fluorostyrenes. J Fluorine Chem 1999;97(1/2): 135–43. [42] Majumdar RN, Niknam MK, Harwood HJ. Synthesis and NMR characterisation of copolymers of methyl acrylate with a-fluorostyrene. Polym Prepr (Am Chem Soc, Div Polym Chem) 1982;23(2):87–8. [43] Marvel CS, Inskeep GE, Deanin RJ, Juve AE, Schroeder CH, Goff MM. Copolymers of butadiene with halogenated styrenes. Ind Engng Chem 1947;39:1486 –90. [44] Alfrey Jr T, Price CC. Relative reactivities in vinyl copolymerization. J Polym Sci 1947;2:101–6. [45] Prober M. The synthesis and polymerization of some fluorinated styrenes. J Am Chem Soc 1953;75:968 –73. [46] Van Hamme MJ, Burton DJ. A facile one-step preparation of chlorofluoromethylene olefins. J Fluorine Chem 1977;10: 131–43. [47] Heinze PL, Burton DJ. Palladium-catalyzed cross-coupling of perfluoroalkenylzinc reagents with aryl iodides. A new, simple synthesis of a,b,b-trifluorostyrenes and the stereoselective preparation of 1-arylperfluoropropenes. J Org Chem 1988;53(12):2714–20. [48] Morken PA, Burton DJ. Preparation of b,b-difluoro-a(trifluoromethyl)styrenes by palladium-catalyzed coupling of aryl iodides with pentafluoropropen-2-ylzinc reagent. J Org Chem 1993;58(5):1167 –72. [49] Davis CR, Burton DJ. Stereoselective preparation of (Z)-a,bdifluorostyrenes. Tetrahedron Lett 1996;37(40):7237–40. [50] Davis CR, Burton DJ. Stereoselective preparation of (Z)-a,bdifluorostyrenes and stereospecific conversion to (E)-a,bdifluoro-b-iodostyrenes. J Org Chem 1997;62(26):9217– 22. [51] Hiyama T, Nishide K, Obayashi M. Practical synthesis and polymerization of trifluorovinylsilanes. A possible precursor of poly(difluoroacetylene). Chem Lett 1984;10:1765–8. [52] Fontana SA, Davis CR, He YH, Burton DJ. The stereoselective preparation of cis and trans-1,2-difluoroethylene synthons. Tetrahedron 1996;52(1):37–44. [53] Liu Q, Burton DJ. Stereospecific synthesis of (E)-a,bdifluorostyrenes. Tetrahedron Lett 2000;41(42):8045–8. [54] Naae DG. Reaction of crystalline fluoro olefins with bromine vapor. 2. Solid-state vs. solution stereospecificity for (E)- and (Z)-1-substituted-2-chloro-F-ethene and -F-propene. J Org Chem 1979;44(3):336–9.

103

[55] Naae DG. Electrophilic bromination of fluoro olefins: syn vs. anti addition. J Org Chem 1980;45(8):1394– 401. [56] Dixon S. Elimination reaction of fluoro-olefins with organolithium compounds. J Org Chem 1956;21:400 –3. [57] Rybakova LF, Panov EM, Kocheshkov KA. Reactions of p-bromo-a,b-difluoro-b-chlorostyrene with organolithium compounds. Dokl Akad Nauk SSSR 1970;193(5): 1080–2. [58] Rybakova LF, Panov EM, Kocheshkov KA. Cis- and trans-a, b-difluoro-b-chlorostyrenes. Zh Org Khim 1975;11(12): 2576–9. [59] Timofeyuk GV, Sorokina RS, Panov EM, Goryalnova LG, Nikitina TS, Pravednikov AN, Kocheshkov KA. Fluorocontaining vinylarylsulfonic acids. SU 287,929; 1970 [60] Panov EM, Rybakova LF, Kocheshkov KA. Synthesis of conjugated polymeric organofluorine compounds. Dokl Akad Nauk SSSR 1970;190(1):122– 4. [61] Panov EM, Rybakova LF, Kocheshkov KA. Open-chain 1,2difluoroethylenephenylenes. Zh Org Khim 1972;8(11): 2362–6. [62] Morken PA, Lu H, Nakamura A, Burton DJ. Convenient preparation and functionalization of 2-metalated pentafluoropropenes. Tetrahedron Lett 1991;32(34):4271–4. [63] Guiot J, Ameduri B, Boutevin B, Lannuzel T. Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group. 13. Copolymerization of vinylidene fluoride with 2-benzoyloxypentafluoropropene. Eur Polym J 2003; 39(5):887–96. [64] Bekker RA, Melikyan GG, Dyathin BL, Knunyants IL. Polyfluorinated enols and their derivatives. II. Perfluoropropen-2-ol: acylation and related reactions. Zh Org Khim 1975; 11(8):1600–4. [65] Bekker RA, Melikyan GG, Dyathin BL, Knunyants IL. Polyfluorinated enols and their derivatives. III. Halogenation, sulfonation, and nitrosation of perfluoropropen-2-ol. Zh Org Khim 1975;11(8):1604 –7. [66] Nakai T, Maruta M. Preparation of polyfluoroenolates. US 4, 910,348; 1987 [67] Qian CP, Nakai T. Perfluoro enolate chemistry: facile generation and unique reactivities of metal F-1-propen-2olates. Tetrahedron Lett 1988;29(33):4119–22. [68] Qian CP, Liu YZ, Tomooka K, Nakai T. Generation and use of lithium pentafluoropropen-2-olate: 4-hydroxy-1,1,1,3,3pentafluoro-2-hexanone hydrate (2,2,4-hexanetriol, 1,1,1,3, 3-pentafluoro- from 1-propen-2-ol, 1,1,3,3,3-pentafluoro-, lithium salt. Org Synth 1999;76:151 –8. [69] Narita T, Hagiwara T, Hamana H, Tomooka K, Katsuhiko YZ, Nakai T. Unique radical addition reactions onto perfluoro-enol esters. Tetrahedron Lett 1995;36(34):6091–4. [70] Narita T, Hagiwara T, Hamana H, Enomoto K, Yoshida Y, Inagaki Y. Radical polyaddition of bis(a-trifluoromethyl-bdifluorovinyl) terephthalate with 1,4-dioxane. Macromol Rapid Commun 1998;19(9):485 –91. [71] Narita T, Hagiwara T, Hamana H, Kitamura K, Inagaki Y, Yoshida Y. Radical addition reaction of 2-benzoyloxypentafluoropropene onto cycloalkanes. J Fluorine Chem 1999; 97(1/2):263–5.

104

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106

[72] Tidwell PW, Mortimer GA. An improved method of calculating copolymerization reactivity ratios. J Polym Sci Part A: Gen Pap 1965;3(1):369 –87. [73] Brown DW, Wall LA. Radiation-induced copolymerization of tetrafluoroethylene and 3,3,3-trifluoropropene under pressure. J Polym Sci, Part A1 (Polym Chem Ed) 1968; 6(5):1367–79. [74] Naberezhnykh RA, Sorokin AD, Volkova EV, Fokin AV. Radiation copolymerization of fluoroolefins. Izv Akad Nauk SSSR Ser Khim 1974;1:232–3. [75] Greenley RZ. Q and e values for free radical copolymerization of vinyl monomers and telogens. In: Immergut H, Abe A, Bloch DR,, editors, 4th ed. Polymer handbook, vol. II. New York: Wiley; 1999. p. 309. [76] Khodzhaev SG, Yusupbekova FZ, Yul’chibaev AA. Synthesis of derivatives of perfluoromethacrylic acid and some polymers made of them. Sb Nauchn Tr-Tashk Gos 1981;667:3448. [77] Sianesi D, Caporiccio G. Polymerization of 3,3,3-trifluoropropene. Makromol Chem 1965;81:264 –7. [78] Ameduri B, Bauduin G, Kostov G, Petrova P, Rousseau A. Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group. Part 7. Copolymerization of tetrafluoroethylene with v-hydroxy trifluorovinyl monomers. J Appl Polym Sci 1999;73(2):189 –202. [79] Guiot J, Ameduri B, Boutevin B. Radical homopolymerization of vinylidene fluoride initiated by tert-butyl peroxypivalate. Investigation of the microstructure by 19F and 1H NMR spectroscopies and mechanisms. Macromolecules 2002;35(23):8694–707. [80] Ameduri B, Bauduin G, Boutevin B, Kostov G, Petrova P. Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group. 9. Bulk copolymerization of vinylidene fluoride with 4,5,5-trifluoro-4-ene pentyl acetate. Macromolecules 1999;32(14):4544–50. [81] Ameduri B, Boutevin B, Kostov G, Petrova P. Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group. Part 10. Copolymerization of vinylidene fluoride (VDF) with 5-thioacetoxy-1,1,2-trifluoropentene for the obtaining of a novel PVDF containing mercaptan side-groups. Des Monomers Polym 1999;2(4):267– 85. [82] Greenley RZ. Free radical copolymerization reactivity ratios. In: Braudrup J, Immergut EH,, editors, 3rd ed. Polymer handbook, vol., II. New York: Wiley; 1989. p. 181. [83] Manseri A, Ameduri B, Boucher M. Copolymerization of vinylidene fluoride with perfluorinated vinyl ethers. Presented at the 15th Winter Fluorine Conference, Saint Petersburg Beach, FL, 14 –19 January, 2001. Presentation #49 [84] Weise JK. Termonomer induced copolymerization of methyl methacrylate and tetrafluoroethylene. Polym Prepr (Am Chem Soc, Div Polym Chem) 1971;12(1):512– 20. [85] Kazennikova GV, Talamaeva TV, Zimin AV, Simonov AP, Kocheshkov KA. Fluorinated styrenes. V. a,b,b-Trifluorostyrenes. Izv Akad Nauk, SSSR, Otd Khim Nauk 1961; 1063–5. [86] Rybakova LF, Panov EM, Nikitina AA, Kocheshkov KA, Karandi IV. Synthesis and properties of trimethylsilyl esters

[87]

[88]

[89]

[90] [91]

[92] [93]

[94]

[95]

[96]

[97]

[98]

[99]

[100]

[101]

[102]

of fluoro-containing vinylbenzenesulfonic acids. Zh Obshch Khim 1976;46(1):117 –21. Sorokina RS, Rybakova LF, Kalinovskii IO, Chernoplekova VA, Beletskaya IP. Synthesis of trifluorostyrene and its derivatives by the reaction of (trifluorovinyl)trimethyltin aryl iodides in the presence of palladium complexes. Zh Org Khim 1982;18(11):2458–9. Heinze PL, Burton DJ. Palladium-catalyzed coupling of (trifluorovinyl)zinc reagents with aryl iodides. An improved synthesis of a,b,b-trifluorostyrenes and the stereospecific preparation of fluorinated 1-phenylpropenes. J Fluorine Chem 1986;31(1):115 –9. Hodgdon RB, MacDonald DI. Preparation and polymerizability of substituted a,b,b,-trifluorostyrenes. J Polym Sci, Part A-1(Polym Chem Ed) 1968;6(3):711–7. Barlett PD, Cohen GM. Dimers of a,b,b-trifluorostyrene. J Am Chem Soc 1973;95(23):7923–5. Tellier F, Sauvetre R, Normant JF. Reactivity of fluorodienes and fluorostyrenes obtained by a palladium catalyzed crosscoupling reaction. J Organomet Chem 1987;331(3): 281 –2981. Coulson DR. Tetrakis(triphenylphosphine)palladium(O). Inorg Synth 1972;13:121– 4. Stone C, Steck AE, Lousenberg RD. Substituted trifluorostyrene compositions (Ballard Power Systems Inc.). US 5, 602,185; 1997 Sanecki P. Variation of transfer coefficient in electrochemical correlations of rs type. Reduction of aromatic sulfonyl fluorides on mercury electrode. Polish J Chem 1992;66(1): 101 –10. Burton DJ, Hansen SW. Generation, spectroscopic detection, and chemical reactivity of fluorinated vinylcopper reagents. J Am Chem Soc 1986;108(14):4229–30. Hansen SW, Spawn TS, Burton DJ. The stereospecific preparation of fluorinated vinylzinc reagents from polyfluorinated vinyl iodides or bromides and zinc metal. J Fluorine Chem 1987;35(2):415–20. Tevlina AS, Ivankin AN, Korshak VV, Baranova NP, Nikitina TS, Rokhlin EM. Copolymerization of a,b,btrifluorostyrene with some vinyl monomers. Mosk. Khim. Tekhnol. Inst., Moscow, USRR, deposited Doc. 1981, Viniti Chem. Abst., 127-81, p. 12 Stone C, Daynard TS, Hu LQ, Mah C, Steck AE. Phosphonic acid functionalized proton exchange membranes for PEM fuel cells. J New Mater Electrochem Syst 2000;3(1):43 –50. Zhuang H, Pearce EM, Kwei TK. Self-association in poly(styrene-co-4-vinylbenzenephosphonic acid) and miscibility of its blends. Polymer 1995;36(11):2237–41. Xu X, Cabasso I. Preliminary study of phosphonate ion exchange membranes for PEM fuel cells. Polym Mater Sci, Engng (Am Chem Soc, Div PMSE) 1993;68:120–1. Kotov SV, Pedersen SD, Qiu W, Qiu ZM, Burton DJ. Preparation of perfluorocarbon polymers containing phosphonic acid groups. J Fluorine Chem 1997;82(1):13–19. Gil’man AB, Rybakova LF, Kolotyrkin VM, Sorokina RS, Grigor’eva GA. Plasma-chemical method for the preparation

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106

[103]

[104] [105]

[106]

[107]

[108]

[109]

[110]

[111]

[112]

[113]

[114]

[115]

[116]

[117]

[118]

of polymers from some halo-substituted styrenes. Soedin Vysokomol, Ser B 1978;20(5):392–4. Watanabe M, Ishiuchi H. Alkaline batteries containing fluorine compounds for corrosion resistance. JP 5,013,070; 1993 Yang ZY, Feiring AE, Smart BE. New ring-containing fluoropolymers. J Am Chem Soc 1994;116(9):4135–6. Feiring AE, Smart BE, Yang ZY. Fluoroalkenyl trifluorovinyl ethers and their preparation and polymerization. PCT International Application WO 9,414,741; 1994 (DuPont de Nemours) Smith Jr DW, Babb DA. Perfluorocyclobutane aromatic polyethers. Synthesis and characterization of new siloxanecontaining fluoropolymers. Macromolecules 1996;29(3): 852–60. Pereta KPU, Krawiek M, Smith Jr DW. Synthesis and thermal cyclopolymerization of heterocycle containing bisortho-diynyl arenes. Tetrahedron 2002;58:10197–203. Grot WG, Molnar CJ, Resnick PR. Perhalocarboxylic acids by oxidation of perhalosulfinic acids. AU 544,027; 1985 (DuPont de Nemours) Desmarteau DD, Martin CW, Ford LA, Xie Y. Sulfonated perfluorovinyl functional monomers. US 6,268,532; 2001 (3M Innovative Properties company) Eisenberg A, Yeager HL. Perfluorinated ionomer membranes. ACS Symposium Series 180, Washington, DC: American Chemical Society; 1982. Smith Jr DW, Chen S, Kumar S, Ballato J, Shah H, Topping C, Foulger S. Perfluorocyclobutyl copolymers for microphonics. Adv Mater 2002;14(21):1585–9. Foulger SH, Jiang P, Lattam A, Smith Jr DW, Ballato J. Optical and mechanical properties of poly(ethyleneglycol) methacrylate hydrogel encapsuled crystalline colloid arrays. Langmuir 2001;17:6023 –6. Foulger SH, Lattam A, Ballato J, Jiang P, Ying Y, Smith Jr DW. Photonic bandgap composites. Adv Mater 2001;13(24): 1898–901. Zengin H, Zhou W, Jin J, Czerw R, Smith Jr DW, Echegoyen L, Caroll D, Foulger S, Ballato J. Carbon nanotube doped polyaniline. Adv Mater 2002;14(20):1480–3. Luo J, Liu S, Haller M, Liu L, Ma H, Jen AKY. Design, synthesis, and properties of highly efficient side-chain dendronized nonlinear optical polymers for electro-optics. Adv Mater 2002;14(23):1763– 8. Smith Jr DW, Boone HW, Traiphol R, Shah H, Perahia D. Perfluorocyclobutyl (PFCB) liquid crystalline fluoropolymers. Synthesis and thermal cyclopolymerization of di(trifluorovinyloxy)-a-methylstylbene. Macromolecules 2000; 33(4):1126– 8. Traiphol R, Shah HV, Smith Jr DW, Perahia D. Bulk and interfacial studies of a new versatile semifluorinated lytropic liquid crystalline polymer. Macromolecules 2001;34(12): 3954–61. Traiphol R, Smith Jr DW, Perahia D. Surface ordering in thin films of liquid crystalline polymers containing fluorinated and protonated segments: neutron reflectometry study. J Polym Sci, Part A (Polym Chem) 2002;40(24):2817–24.

105

[119] Townsend PH, Shaffer EO, Mills ME, Blackson J, Radler MJ. Interconnect process technology using perfluorocyclobutane (PFCB). Materials Research Society Symposium Proceedings: Low-Dielectric Constant Materials II, vol. 443.; 1997. p. 33–40. [120] Fishbeck G, Moosburger R, Kostrzewa C, Achen A, Petermann K. Single-mode optical waveguides using a high temperature stable polymer with low losses in the 1.55 mm range. Electron Lett 1997;33(6):518– 9. [121] Perretie D, Bratton L, Bremmer J, Babb DA, Chen Q, Judy JH. Perflurocyclobutane containing aromatic ether polymers as an electronic grade resin for flat panel displays. In: Proceedings of SPIE—The International Society for Optical Engineering: Liquid Crystal Materials, Devices, and Applications II, 1911.; 1993. p. 15–20. [122] Tumolillo Jr TA, Thomas A, Ashley PR. Multilevel registered polymeric Mach-Zehnder intensity modulator array. Appl Phys Lett 1993;62(24):3068–70. [123] Smith Jr DW, Babb D, Shah H, Hoeglund A, Traiphol R, Perahia D, Boone H, Langhoff C, Radler M. Perfluorocyclobutane (PFCB) polyaryl ethers. A versatile coating material. J Fluorine Chem 2000;104(1):109–17. [124] Beckerbauer, R. Fluorocarbon ethers. US 3,397,191; 1968 (DuPont de Nemours) [125] Clement KS, Ezzel BR, Babb DA, Richey WF. Reactive compounds containing perfluorocyclobutane rings. Dow Chemical US 5,037,919; 1991 [126] Clement KS, Ezzel BR, Babb DA. Reactive compounds containing perfluorocyclobutane rings. US 5,021,602; 1991 (Dow Chemical) [127] Bartmann E, Plach H, Eidenschink R, Reiffenrath V, Pauluth D, Poetsch E, Schoen S, Meyer V, Junge M, Hittich R. Vinyl compounds, and a liquid-crystalline medium. US 5,403,512; 1995 (Merck) [128] Babb DA, Clement KS, Ezzel BR. Perfluorovinyl compounds. US 5,023,380; 1991 (Dow Chemical) [129] Babb DA, Clement KS, Richey WF, Ezzel BR. Perfluorocyclobutane ring-containing polymers. US 5,037,917; 1991 (Dow Chemical) [130] Babb DA, Ezzel RB, Clement KS, Richey WF, Kennedy AP. Perfluorocyclobutane aromatic ether polymers. J Polym Sci, Part A: Polym Chem 1993;31(13):3465–77. [131] Kennedy AP, Babb DA, Bremmer JN, Pasztor Jr AJ. Perfluorocyclobutane aromatic ether polymers. II. Thermal/ oxidative stability and decomposition of a thermoset polymer. J Polym Sci, Part A: Polym Chem 1995;33(11):1859– 65. [132] Babb DA, Rondan NG, Smith Jr DW. Novel step-growth polymers from the thermal [2p þ 2p] cyclodimerization of fluorinated olefins. Polym Prepr (Am Chem Soc, Div Polym Chem) 1995;36(1):721–2. [133] Bernett WA. Hybridization effects in fluorocarbons. J Org Chem 1969;34(6):1772 –6. [134] Wang SY, Borden WT. Why is the p bond in tetrafluoroethylene weaker than that in ethylene? An ab initio investigation. J Am Chem Soc 1989;111(18):7282– 3. [135] Cheatman CM, Lee SE, Laane J, Babb DA, Smith Jr DW. Kinetics of trifluorovinyl ether cyclopolymerization via Raman spectroscopy. Polym Int 1998;46(4):320–4.

106

R. Souzy et al. / Prog. Polym. Sci. 29 (2004) 75–106

[136] Babb DA, Clement KS, Ezzel BR. Polymers containing perfluorocyclobutane ring. US 5,159,038; 1992 (Dow Chemical) [137] Kim YK, Pierce OR, Bajzer WX, Smith AG. New hybrid fluorosilicones monomers. Polym Prepr (Am Chem Soc, Div Polym Chem) 1971;12(1):482 –8. [138] Babb DA, Snelgrove RV, Smith JrDW, Mudrich SF. Novel step-growth polymers from the thermal [2p þ 2p] cyclopolymerization of aryl trifluorovinyl ether monomers. ACS Symposium Series 624: Step-Growth Polymers for HighPerformance Materials; 1996. p. 431 –41. [139] Boone HW, Smith Jr DW, Babb DA. A new aromatic perfluorocyclobutane polymer: synthesis and thermal characterization of 1,3,5-tris[(4-trifluorovinyloxy)phenyl]benzene. Polym Prepr (Am Chem Soc, Div Polym Chem) 1998;39(2): 812–3. [140] Xu Y, Loveday DC, Ferraris JP, Smith Jr DW. A new phenylthiophene derivative with crosslinking capability. Polym Prepr (Am Chem Soc, Div Polym Chem) 1998; 39(1):143–4. [141] Ji J, Narayan-Sarathy S, Neilson RH, Oxley JD, Babb DA, Rondan NG, Smith Jr DW. [ p-((Trifluorovinyl)oxy)phenyl]lithium: formation, synthetic utility, and theoretical support for a versatile new reagent in fluoropolymer chemistry. Organometallics 1998;17(5):783– 5. [142] Narayan-Sarathy S, Neilson RH, Smith Jr DW. Hydrosilation polymerization and thermal cure of divinyl trifluorovinyl ether monomers. Polym Prepr (Am Chem Soc, Div Polym Chem) 1998;39(1):609–10. [143] Ford LA, Smith Jr DW, Desmarteau Jr DD. New aromatic perfluorovinyl ether monomers containing the sulfonimide acid functionality. Polym Mater Sci Engng (Am Chem Soc, Div PMSE) 2000;83:10–11. [144] Rizzo J, Harris Jr FW. Perfluorocyclobutane-containing silarylene –siloxane polymers with pendant trifluoropropyl groups. Polym Prepr (Am Chem Soc, Div Polym Chem) 1999;40(2):874–5. [145] Babb DA, Boone HW, Smith Jr DW, Rudolph Jr PW. Perfluorocyclobutane aromatic ether polymers. III. Synthesis and thermal stability of a thermoset polymer containing triphenylphosphine oxide. J Appl Polym Sci 1998;69(10): 2005–12. [146] Miyaura N, Yanagi T, Suzuki A. The palladium-catalyzed cross-coupling reaction of phenylboronic acid with haloarenes in the presence of bases. Synth Commun 1981;11(7): 513–9. [147] Rizzo J, Harris FW. Synthesis and thermal properties of fluorosilicones containing perfluorocyclobutane rings. Polymer 2000;41(13):5125– 36.

[148] Neilson RH, Robert H, Ji J, Narayan-Sarathy S, Oxley J, Smith JrDW. Synthesis and characterization of new trifluorovinyl ether derivatives of phosphorus and silicon. Book of abstracts. 213th ACS National Meeting, San Francisco, April 13 –17; 1997. [149] Desmarteau DD. Novel perfluorinated ionomers and ionenes. J Fluorine Chem 1995;72(2):203–8. [150] Desmarteau DD, Ma JJ, Tu MH, Liu JT, Thomas B, McClellan J. Synthesis and properties of new bis[(perfluoroalkyl)sulfonyl]imide ionomers for fuel cells. Polym Mater Sci Engng (Am Chem Soc, Div PMSE) 1999;80:598–9. [151] Creager SE, Savett S, Thomas B, Desmarteau DD. New bis[(perfluroralkyl)sulfonyl]imide ionomers for PEM fuel cells. Polym Mater Sci Engng (Am Chem Soc, Div PMSE), (Polym Mater Sci Engng) 1999;80:600. [152] Creager SE, Summer JJ, Baily RD, Ma JJ, Pennington WT, Desmarteau DD. Equivalent weight and crystallinity effects on water content and proton conductivity in bis[(perfluoroalkyl)sulfonyl]imide-based ionomers. Electrochem Solid State Lett 1999;2(9):434– 6. [153] Qing FL, Wang R, Li B, Zheng X, Meng WD. Synthesis of 4, 6-disubstituted pyrimidines via Suzuki and Kumada coupling reaction of 4,6-dichloropyrimidine. J Fluorine Chem 2003; 120(1):21–4. [154] Topping CM, Jin J, Ligon SC, Patil AV, Fallis S, Irvin JA, Desmarteau DD, Smith Jr DW. Toward crown ether containing semifluorinated polyarylene amides for lithium battery membranes. Polym Prepr (Am Chem Soc, Div Polym Chem) 2002;43(1):486–7. [155] Souzy R, Ameduri B, Pineri M, Marsacq D. Fluoro membranes for fuel cell applications. FR 0,210,159; 2002 (Commissariat a` l’Energie Atomique) [156] Souzy R, Ameduri B, Boutevin B, Virieux D. Synthesis and characterization of a new monomer: 4-phosphonic acid-[(a, b,b-trifluorovinyl)oxy] benzene as original. Submitted for publication [157] Heinicke J, Jux U, Kadyrov R, He M. P/O ligand systems: synthesis and reactivity of primary and secondary Ophosphinophenols. Heteroat Chem 1997;8(5):383– 96. [158] Tavs P. Reaction of aryl halides with trialkyl phosphites or dialkyl phenylphosphonites to aromatic phosphonates or phosphinates by nickel salt catalyzed arylation. Chem Ber 1970;103(8):2428–36. [159] Souzy R, Ameduri B, Boutevin B. Synthesis and polymerization of fluoromonomers bearing a functional side group. Part 18. Radical (co)- and (ter)polymerization of 4-[(a,b,btrifluorovinyl)oxy]bromobenzene with vinylidene fluoride, and/or hexafluoropropene, and/or chlorotrifluoroethylene, and perfluoromethyl vinyl ether. Submitted for publication.