Synthesis and properties of polyamides with diphenylene anthracene fragments in the macromolecules

49

Synthesis and properties of polyamides

5. 6. 7. 8. 9. 10.

11.

HINA, A. I. KORETSKAYA and M. P. BABUSI-IKINA, Ibid. 1328: 644, 1986 (Not'translated in Polymer Sei. U.S.S.R.) V. N. TSVETKOV, Zhestkotsepnye polimernye molekuly (Rigid Chain Polymer Molecules). Leningrad, 1986 V. N. TSVETKOV, P. N. LAVRENKO and S. V. BUSHIN, Usp. khim. 51: 1968, 1982 G. C. BERRY, Disc. Faraday Sot., 49, 121, 1970 J. E. HEARST and W. H. STOCKMAYER, J. Chem. Phys. 37: 1425, 1962 H. YAMAKAWA and M. FUJII, Macromolecules 6: 407, 1973 N. V. POGODINA, N. N. YEVLAMPIYEVA, V. N. TSVETKOV, V. V. KORSHAK, S. V. VI. NOGRADOVA, A. L. RUSANOV, I. I. PONOMAREV and T. V. LEKAYE, Vysokomol soyed. A30: 1198, 1988 (Translated in Polymer Sci. U.S.S.R. 30: No. 6, 1988) S. BROERSMA, J. Chem. Phys. 32: 1632., 1960

Polymer Science U.S.S.R. eel. 31, No. 1, pp. 49-55, 1989 Printed in Poland

0032-3950189 $I0.00+.00 1990 Pergamon Press plc

SYNTHESIS AND PROPERTIES OF POLYAMIDES WITH DIPHENYLENE ANTHRACENE FRAGMENTS IN THE MACROMOLECULES* S. V. VINOGRADOVA, YA. S. VYGODSKII, N .

A.

CHUROCHKINA,

L. B. TUNIK, V. V. KORSHAK (dec.), B. V. KOTOV and V. I. BYEREDYAYEV Nesmeyanov Institute of Elemento-Organic Compounds (Received 28 October 1987)

The patterns of low temperature polycondensation of 9,10-bis-(4'-aminophenyl)anthracenv and terephthaloyl chloride in amide solvents have been studied. High molecular weight homoand co-polyamides have been obtained based on 9,10-bis-(4'-aminophenyl)anthracene, p-phenylene diamine, 9,9-bis-(4'-aminophenyl)fluorine, 5(6)-amino-2(4'-aminophenyl)benzimidazolo and the chloranhydrides of adipic, sebacic, tere- and iso-phthalic acids, 2,2-bis-(4-carboxyphenyl)hvxafluoropropane and 3,3-bis-(4'-carboxyphenyl)phthalide. Strong films have been obtained from homo- and co-polyamides soluble in amide solvents.

THE successful use of aromatic PAs with parasubstituted benzene nuclei primarily poly-p-phenylene terephthalamide in the f o r m of high strength and high modulus fibres has stimulated investigations into the folmulation of new polyamides of this type with raised rigidity of the rod-like macromolecules. A very promising approach to the creation of such polymers is the synthesis of PAs with symmetrical highly condensed aromatic fragments in the macromolecules, for example, anthracene fragments [1, 2]. * Vysokomol. soyed. A31: No. 1, 45-50, 1989.

50

S. V. V~OOP.XDOVAet

al.

The present work is concerned with some aspects of the synthesis of PAs with 9,10-diphenyleno anthracene fragments in the macromolecules and their properties

/ \ ~__//

The presence between the anthracene and amide groups of phenyl groups might promote the appearance of some flexibility of their chains and hence better solubility o f PAs in organic solvents as compared with known 2,6-disubstituted anthracene-containing PAs [2]. This is of no little importance both for the actual process of synthesis of such rigid chain polyamides for which, as will be shown below, solubility in the reaction medium during synthesis is one of the main conditions for the formation of polymers with high MW and for the formation from them of film materials. Polyamides with 9,10-diphenylene anthracene fragments in the macromolecules were synthesized by low temperature polycondensation in amide solvents in the presence of LiCl from 9,10-bis-(4'-aminophenyl) anthracene and various dichloranhydrides of aromatic and aliphatic dicarboxylic acids-adipic, sebacic and tere- and iso-phtlialic and 2,2'-bis-(4-carboxyphenyl) hexafluoropropane and 3,3-bis-(4'carboxyphenyl) phthalide. Following the synthesis of polydiphenylene anthracene terephthalamido (PAT)

--HN - \ ~ _ / - ~ _ ~ ~-

~_ ~ , ~ / - NHOC- - /fi--~ CO~/-

(one of the most rigid chain PAs) we studied the effect of the nature of the solvent, the concentration of monomers and LiC1 and also the temperature and duration of the reaction on the MW of the polymer. As Table 1 shows the molecular weight, r/z, of the PAT formed changes within wide limits with the nature of the solvent used. Thus, the synthesis in N-methyl-2-pyrrolidone and especially in hexamethylphosphortriamide in presence of LiCl (in absence of LiC1 9,10-bis-(4'-aminophenyl) anthracene does not dissolve in these solvents) leads to the formation of PAT with rlz. in H2SO4 not ex~eding 0.75 dl/g (Table l, experiments 1-4). This may be due to the poor solubility of the polymers in such solvents during their synthesis and their associated rapid sedimentation. With hexamethylphosphortriamide as reaction medium in which PAT precipitates from solution within 2-3 rain of the start of synthesis r/z. of the polymer is considerably lower (0.29-0.30 dl/g) than when the reaction is conducted in N-methyl-2-pyrrolidon¢ in which PAT precipitates from solution within 15-20 min (rh. = 0"71-0.75 dl/g). Increase in the PAT concentration in these solvents from 8 to l0 ~o makes virtually no difference to t/l. of the polymer (Table l, experiments 1-4).

Syathasis and propartics of polyamides

51

The magnitude fine reaches its largest values when PAT is synthesized in a mixture of N-methyl-2-pyrrolidone and hexamethylphosphortriamide, volumetric ratio 2:1, in presence of 5 Yo LiC1 (Table I, experiments 6-8). In such a mixed solvent PAT during its synthesis is in the dissolved state which explains why high ~h, values are reached (an exception is PAT obtained with a smaller amount of LiC1 so that during synthesis it remains in the form of a suspension (Table 1, experiment 5)). With increase in the PAT TABLB 1.

EFFECT OF THE NATURE OF THE SOLVENT AND THE AMOUNT OF

LiCI ON

~ln OF

PAT OBTAINED

BY LOW TEMPERATURE POLYCONDENSATION (TEMPERATURB OF SYNTHESIS 20°C, DURATION 2 h r )

Synthesis of PAT concontraLiCI, ~ of[ tion of Solvent Exp., No. type of reaction volume of PAT in medium solvent solution, % HexamethylphosphortriSediment amido Ditto 10 ), N-methyl-2-pyrrolidone 8 Viscous susponsion 10 Ditto Ditto Mixture of N-methyl-28 pyrrolidone and hoxamethylphosphortriamide ( 2 : 1 ) by volume )) 8 Solution Ditto I0 Ditto )) 12 Ditto ))

(H2SO,) dl/g* 0"29 0"30 0"71 0"75 0"82

1-00 1"40 1"91

* Determined for 0.05 g polymerin 10.0 ml H=SO, at 25°C.

concentration in solution from 8-12 ~o its rh. value almost doubles (Table 1, experiments 6-8). The concentration of the polymer in solution cannot be raised above 12 Vobecause of the limited solubility of 9,10-bis-(4-aminophenyl)anthracene in the mixed solvent (its maximum concentration in such a solvent with 5 ~o LiCl in 0.25 mole/l, or 12~o of the concentration of PAT in solution). Thus, the optimal conditions for the synthesis of PAT are the reaction medium-mixture of N-methyl-2-pyrrolidone and hexamethylphosphortriamide (2:1 by volume), concentration of monomers each 0.25 mole/L, concentration of LiC1 5 ~o (of the solvent), duration of reaction 2 hr, temperature of the reaction 20°C. In these conditions we synthesized PAs with 9,10-diphenylene anthracene fragments in the macromolecules from 9,10-bis-(4'-aminophenyl)anthracene and the above indicated chloranhydrides of dicarboxylic acids. The properties of the PAs obtained arc indicated in Table 2. Analysis of Table 2 shows that PAs with 9,10-diphenylene anthracene fragments in the macromolecules judging from the t/no values are high molecular weight compounds

52

S.V. VmOOnADOVAet al.

and apart from the polymers containing residues of isophthalic and diphenylphthalide dicarboxylic acids (experiments 4 and 6) are crystalline. Comparison of the solubility data for the polymers indicates that the effect of the physical structure of the polymer on TABLB 2. SYNTH~S OF PAs w r m

9,10-DH'H~NYLBNB ANTHRAC~NB FRAGMBNTS IN TI-IB MACROMO. I.,ECUI,ES*

Solubility of polymert i

I'~lm

Experiment, No.

-R-

(H=SO,)

T%~.t

dl/g n.s. n.s.

n.s.

n.So

n.s.

s.

s s

3

0.53 0.70 0.68: 1.91

n.s.

n.8.

n,s.

s

280 240 Above T. docomp

4

1.20

n.s.

n.$.

n.$.

s

Ditto

1.10 1.05:

n.s.

S

p~

s

S

IJ

--(CII~)4---(CH2).--

CF,

CFs

0.85 ~\/

o

0.83*

N/\CO * In expeximvnts 1-3 and 5 polymers crystalline; 4 and 6 amorphous t Here, and hereafter, s. is soluble; n.s. insoluble. * Determined for 0.05 g polymer in 10"0 ml N-methyl-2.pyrrolidone at 25°C.

its solubility is ambiguous and in some cases the chemical structure of the polymer assumes greater importance. In fact, crystalline PAs based on the chloranhydrides of adipic and terephthalic acids (experiments 1 and 3) and the amorphous PA. of isophthaloyl chloride (experiment 4) dissolve only in H2SO4 and CF3SO2OH. At the same time the crystalline PAs based on the chloranhydrides of sebacic acid and 2,2-bis-(4carboxyphenyl) hexafluoropropane (experiments 2 and 5) and also the amorphous PA containing residues of diphenylphthalide dicarboxylic acid (experiment 6) dissolve not only in H2SO4 and CFsSO2OH but also in amide solvents. The solubility of these polymers in amide solvents is apparently due to different factors: for some PAs to the

53

Synthesis and properties of polyamides

presence of voluminous hexafluoropropyl and non-symmetrial phthalide groupings (experiments 5 and 6) which impast solubility in organic solvents even to rigid chain PIs [3, 4] and for others to the content of the long methylene chains increasing the flexibility of the polymer chains (experiment 2). From the PAs with hexafluoropropyl and phthalide groupings soluble in amide solvents films are obtained with a strength at rupture 70-90 MPa and relative elongation at rupture 10 ~o; films of a PA containing sebacic acid residues are very cloudy and brittle which may be due to additional ordering of the polymer during formation of films. To improve the solubility of rigid chain and crystalline PAs with 9,10-diphenylene anthracene fragments in the macromolecules it appears necessary to reduce the fraction of these fragments by introducing into the molecular chains other less condensed but yet thermally stable groupings. This may be achieved by synthesizing copolymers the properties of which, as is known, are influenced not only by the chemical structure of the starting substances and their ratios but also by the microstructure of the copolymer. for this purpose CPA-1, CPA-2 and CPA-3 copolyamides were obtained respectively from terephthaloyl chloride, 9,10-bis-(4'-aminophenyl) anthracene and p-phenylene diamine or 9,9-bis-(4'-aminophenyl)fluorene or 5(6)-amino-2-(4'-aminophenyl)benzimidazole containing in their macromolecules phenylene, fluorene and benzimidazole groupings

@ --HN--#---\\--/---N_ .f-~,--NHOC--f~--~.x--COItN-Ar--NH--, :

\~/

~ / \\

N-~-'~/

",~_~/

"

,,,

//

where Ar=--.~--"3-- (CPA-1),

- @ 9< !,)

(;

\ ~ x -?--c /X--~ (CPA-2)a n- ,o/ '--,\% N~/--(CPA-3),

NH

The properties of the copolyamides are indicated in Table 3 from which it follows that these high molecular weight copolymers have an amorphous structure and do not soften below the start of decomposition apart from CPA-3 containing 70 and 90 mole Yo benzimidazole groups softening respectively at 300 and 260°C (experiments 8 and 9). The solubility of the copolyamides in N-methyl-2-pyrrolidone (they do not dissolve in DMAA and DMFA) except for CPA-1 is ensured by the high content of the blocks with fluorene (>I 80 mole ~ or benzimidazole (i> 70 mole ~{) groupings. CPA-ls whatever their composition dissolve only in H2SO4 and CFaSO2OH. In view of the specifics of the mode of obtaining the copolyamides by low temperature polycondensation (the solid dichloranhydride of a dicarboxylic acid is introduced into the solution of diamines) and also the lower reactivity of 9,10-bis-(4'-aminophenyl) anthracene as compared with other diamines used for copolycondensation such polymers must in the main have a block structure [5] which also accounts for their poorer solubility in N-methyl-2-pyrro-

S. V. VmOOL~,DOVAet aL TABLe 3. P l t o p ~

OF COPOLYTEREPI-ITHALAMIDESWITH 9,10-DIPHeNYLeNe ANTHRAC~NBFRAOMENTS IN T I ~ MACROMOLeCUL~ ~o

Experiment No.

Ratio of starting diamines (moles)* ANT

PPDA

AFL

ABIZ

Solubility of copolyamides 171a (H~SO4) N-methyl2-pyrrol- H2S04 di/g idone

CPA-I

! 1°2l I 1.01 ,.s. 0-5 (>1

0-5 0.9

4

0-3

--

5

0-2

1.20 1-68

Above T. decomp. ditto

n.s. n.s.

),

CPA-2 0-7 0-8

--

0-92

[

n.s.

0-72

[

s

Above T. decomp. ditto

0- 80t

0-1

0.9

0-80

s

0.85t

0.4 0- 3

-

1"66 A 3 1'42 1"20 1.52t

0-1

n.s.

s

s

s

Above, T. decomp. 300

s

s

260

1.30t * A N T is 9,10-bis-(4-~mlnophanyl) anthracene; PPDA is p-phenylene diamine; A F L is 9,9.bls-(4-~-nlnopheayl)fluoreae; ABIZ is 5 (6)-amino-2(4-Aminophenyl)ben~imldazole. t Determined on 0.05 g polymer in 10.0 ml N-methyl-2-pyrrolidone at 25eC.

lidone than might have been expected for such copolymers. Strong films could be obtained f r o m CPA-2s and CPA-3s each containing 90 mole ~o fluorene and benzimidazole groupings (Table 3, experiments 6 and 9). Their strength at rupture is respectively 100 and 130 M P a and the relative elongation at rupture 8 and 10~o. Starting substances. Tere- and iso-phthaloyl chlorides (MP respectively 83-84 and 43--44°C [6]); the chloranhydrides of adipi¢ and sebadc acids and 3,3-bis-(4'-carboxyphenyl)phthalide (BP respectively 105/266 Pa and 135-136/266Pa and 240-250/0.5 Pa [7, 8] were purified by vacuum distfllation.; the chloranhydridv of 2,2-bis-(4-carboxyphenyl)hexafluoropropane (MP 93"5-94"5°C [3]) by rccrystallization from hexanv; p-phenylone diamin~, 9,9-bis-(4'-aminophenyl)fluoreno, 9,10-bis(4'-aminophcnyl)anthracene and 5(6)-amino-2-(4"-aminophenyl)benzimidazole (MP respectively 147-148, 233.5-234. 0, 322-324 and 234-235°C [6, 9-11 ]) by vacuum sublimation; N-mothyl-2-pyrrolidone and hexamethylphosphortriamide were purified by distillation/n vacuo over calcined molecular sieves (type 4 A), their BPs respectively 84°/1"3 kPa and 120°/133 Pa [12, 13]. The constants of the starting substances corresponded to the published data. Synthesis of PAT. To a solution of 0-7209 g (0. 002 moles) of 9,10-bis-(4'~minophenyl)anthra¢ene and 0.4 g LiCI in 8 mi of a mixture of N-methyl-2-pyrr01idone and hcxamethylphosphortriamido

Synthesis and prol~rties of polyamides

35

(2: I) was added at 0°C 0.406 g (0.002 moles) terephthaloyl chloride and agitated for 20 rain at 0°C and for 2 hr at 20°C. The reaction solution was diluted with the solvent mixture indicated and the polymer isolated by precipitation into water. #~. of the polymer in H2SO4 1.91 dl/g. The softening points of the polymers were determined from the thermomechanical curves (heating rate I. 5 dog/rain, stress 0. 08 MPa) as the point of intersection of the tangents to the slope of the thermomechanical curve in the region of the appearance of heavy strains of the polymer. Preparation of films from the polymers. Films of the polymers wore obtained by casting 4 - 5 ~ solutions in D M A A or N-methyl-2-pyrrolidone onto a glass support followed by evaporation of the solvent at 80-100°C. The mechanical properties of such films wore evaluated with the Polyani instrument at room temperature.

Translated by A. CRozY REFERENCES 1. G. I. KUDRYAVTSEV and T. I. SHEIN, K.him. volokna, 2, 5, 1978 2. A. FRAZER, B. C. ANDERSON, L. C. GARVER and T. FUKUNAGA, J. Polymer Sci. Polymer Chem. Ed. 23: 277, 1985 3. B . R . LIFSHITS, T. Kh. DYMSHITS, N. P. GAMBARYAN and I . L . KNUNYANTS, ZhVKhO im Mendeleyeva 11: 469, 1966 4. S. V. VINOGRADOVA, G. L. SLONIMSKII, Ya. S. BYGODSKII, A. A. ASKADSKII, A. I. MZHEL'SKII, N. A. CHUROCHKINA and V. V. KORSHAK, Vysokomol. soyed. A l l : 2725, 1969 (Translated in Polymer Sci. U.S.S.R. 11: 12, 3098, 1969) 5. V. A. VASNEV and S. I. KUCHANKOV, Usp. khimii 42: 2194, 1973 6. W. UTERMARK and W. SCHICKE, Schmelzpunktabellen Organischer Verbindungen, Berlin, 1963 7. S. V. VINOGRADOVA and V. V. KORSHAK, Dokl. Akad. Nauk SSSR 123: 849, 1958 8. V. V. KORSHAK, S. V. VINOGRADOVA, G. L. SLONIMSKII, Ya. S. VYGODSKIII, S. N. SALAZKIN, A. A. ASKADSIgII; A. I. MZHEL'SKII and V. P. SIDOROVA, Vysokomol. soyed. A10: 2058, 1968 (Translated in Polymer Sci. U.S.S.R. 10: 9, 2395, 1968) 9. Great Britain Pat. 467824, Chem. Abstr. 31: 8944, 1937 10. A. ETIENNE and J. C. ACRES, Bull. see. chim. France, 9/10, 727, 1951 11. G. L. TUDOROVSKAYA, T. A. ffd~LDATOVA, N. V. NOVOZHILOVA, L. S. VASHCHILO and N. V. FEDLYAINOVA, Zh. fiz. khimii 49: 3005, 1975 12. A. J. PARKER, Chem. Revs. 69: 1, 1969 13. A. NORMAN, Usp. khim. 39: 990, 1970