Synthesis of polymers and copolymers based on N-vinylamides containing anthracene type luminescent groups

Polymer Science U.S.S.R. Vol. 29, No. 3, pp. 669-675, 1987

0032--3950/87 $10.00+.00 ,i:) 1988 Pergamon Press plc

Printed in Poland

SYNTHESIS OF POLYMERS AND COPOLYMERS BASED ON N-VINYLAMIDES CONTAINING ANTHRACENE TYPE LUMINESCENT GROUPS* M. G. KRAKOVYAK,V. B. LUSHCHIK, T. D. ANAN'EVA, YE. F. PANARIN, M. V. SOLOVSKII, O. P. GORBUNOVA, I. I. GAVRILOVA,YU. E. KIRSH, V. D. PAUTOV, M. R. RAMAZANOVAand YE. V. ANUFRmW High Polymer Institute, U.S.S.R. Academy of Sciences (Received 5 August 1985)

Methods have been developed for the synthesis of polymers and copolymer~ based on N-vinylamides (N-vinylpyrrolidone, N-vinylcaprolactam and N-methyl-N-vinylacetamide) containing 9-alkylanthracene type luminescent groups. It was desired that the intramolecular mobility and intramolecular strueturation processes of these polymers and copolymers should be investigated in water and in organic solvents to shed light on molecular mechanisms of their interaction with polymers of various structural types, and with low molecular weight compounds with the aid of the luminescent groups (labels). The methods employed are based on the interaction of functional groups of the (co)polymers (of carboxyl, hydroxyl, amino and aldehyde types) with appropriate reagents (9-anthryldiazomethane, 9-anthrylmethylisocyanate and 9-anthrylmethylamine). AMONGthe synthetic water-soluble polymers that are of particular interest to investigators are (co)polymers based on N-vinylamides (N-vinylpyrrolidone, N-vinylcaprolactam and N-methyl-N-vinylacetamide) [1]. The extent and the ranges of application of these (co)polymers are constantly expanding. For instance, poly-N-vinylpyrrolidone is used not only in medicine, but also by the food, textile, and pharmaceutical industries, and in agriculture [1-4]. Copolymers based on N-vinylpyrrolidone containing amine, carboxyl, hydroxyl and aldehyde groups are used to modify enzymes and also as carriers of biologically active substances [2, 5, 6]. Selection of the most fitting and appropriate chemical structure of polymers at~d copolymers of N-vinylamides is necessary when resolving various practical problems and with a view optimization of conditions of utilization of these (co)polymers. This calls ~or study of the imramolecular mobility and intramolecular structuration ,_~l"the p~,~N-vinylamides, as well as for investigation of molecular mechanisms of their interactio1~ with polymers of various types and with low molecular weight compounds, along wi;h ~m analysis of factors leading to stabilization or to disintegration of complexes formed in this way. When research of this nature is carried out at the molecular lcvel il is nco essary to employ methods that will enable polymers to be investigated in extremely di* Vysokomol. soyed. A29: No. 3, 598-603, 1987. 669

670

M.G.

KRAKOVYAK et al.

lute solutions (where the polymer concentrations may be as low as some ionicsandths per cent) and in various solvents (in aqueous media with differing pH and ionic strength values in organic solvents). In addition, investigations of intermolecular interactions have to ensure that each of the components of a multicomponent polymer system may be studied. All of these requirements are satisfied when the polarized luminescence method is used [7-9]. To do so it is first of all n=cessary that luminescent groups, i.e. "lab=Is", generally amounting to ,,~0.1 mole ~o, viz. ,,, 1 label per 1000 polym~r,an~s, should be attached to the polymer being investigated (or to a particular.e61m#orl~(nt of a complex polymer system). Groups with a 9-alkylanthracene type J~icttothr~ {17-9] are particularly well suited to use as luminescent labels or markers4tt~ft~c~ inqvol~ing use of the polarized luminescence method. The present p ae~,fjis.~i~.~p~,lgt~t'~t~ipf methods whereby polymers and copolymers of N-vin~lamides containing luminescent groups with a 9-alkylanttlracene type structure may oe prep~irea. In general polymers that contain covalently linked anthracene groups may be prepared by c o p o l y m e r i ~ i 6 i f ? ~ ' ~ a ~ ~i~/6/riei'~'vdtth ta'~a'llqa~/fir/tT~L0q'q/f6~e ~o) of anthracene-cor~lnlnz monomers or*b~/re~ic~mgf~in.chonh~ ~our~s .of ~ ilJacromole'ddo.attomptod.dOblmepara~,lmtV-M-,~l~lamides l~rovidod~~ith.c~nthra~mi~-~combining labeq~ bytrttearl~ of-,mditml~l~olymet,iza~tion¢tag-mg,t~s~m,e~tamplete-n~ledpotsn~or~zation .f~Zt,~ll~;~'l(~r~i't:)I!P~il)(~(O% ~} :~Ji : Q I , ' ¢ i ; U } i ~ ' i~$ir(}i)OlH!~ lo,:t(-fito~;v~J~U '~dl m,) l):~zl;,t 91.~ b ' J y t d u

unsuccessiuL ~xte numt~er ~r anmracene groups m tne reacuon system was snarmy, ;re.311,(,(l!)il(~}XJJlJJ~;if[lfTt}}-V/ /~i|Li~J]D; ,!I;(HIIIIfTT~J~ JTIIc'II~')t|~J L~I)'Tt'I'~II[Jj I ) l l f ; tJllllllli , J ~ ( t - l | ) ~ l l duced during the polymerizatmn p r o c ~ f i ~ , ~ l ~ , ~ l ~ i l l g ~ o ~ 1 1 ~ , ~ l ~ l ~ m b = i ~ 1 3 ~ , ~ ¢ data, contained scarcely any of these groups. The results of control tests show that the dis~..rJ~atalW.~,rlOtMue.,,to tW~I.o7,a..d~,i~i/31Z9f ,l~r~yjBylp.y~rplidopeifOe~he ,a~hrgq~.~rtg, ~.dditi~m~o£ tgr~wi~g, ra0wortg6iFals..,,fo,.,.oJathmceft¢,~r~0g~:le~d~ng S~~th¢~;formgti0~ ,of, 9~dOrdJkydroalghr~n¢.:~14p~t~s: ,~t tYP%~, ~Jxm e, 9p[icaL ~1~¢rg¢ ~ d~ffc~rr~ e 4 J y ~ /e-xX / \/\([m'

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r,,:.M ,~1~r~liy~,:~o,t.ho~: ,(g~dgi~fi~o fJ!4p~in~c~ ~,[igro~lps,~ (qq)poly~n,ersl.o~N-yinyb" amiale~ .b~,moo,n,S,o~pot~Irr~igo,abg~ou~ r¢.#et~a~ ~3'~b~ .c~fr~ie6/~;utjf their, m~,c:romolo.-, ¢ules,contadn $ ~ . i ' ~ gr~t~PS.~I~. ~ g ¢0~s¢,of,~o~!~m¢~ ,th~ '~J~h~.~un~ts.,~o~taimpg f~n¢-, tionaLgrou~ 61iho¢~pe|ymcrs,;thgt a r~ us¢4! in~r~¢.tio~ a~-tt~li,~,5-~30m~e~o Crfits bear~ irtg -~box~l, ~ld~hv,d ~ l~ydroK~ o.r./~mi,n~ g~o,ups)i gn~,il~sig~i~.ar~l; f r ~ : g l , o f / t h ~ groups may be used for reactions with the corresponding anthracene-containing reactants. If on the other hand one is investigating t l m ~ v i w l a m i d r # . h ~ g m o r , ( ¢ r to be ~Or)

Polymers and copolymersbased on N-vinylamides

67i

more precise, a polymer in whose chains the number of N-vinylamide units of the basic structure approximates to 100 ~/~),units (~0.1 mole 700)that are disposed along the polymer chains or at the chain ends, and contain reactive groups will be incorporated in poly-N-vinylamide macromolecules during their formation or in subsequent transformations.

Addition of anthracene-containing luminescent groups to (co)polymers of N-vinylamides containing carboxyl groups. The addition of 9-alkylanthracene groups to carboxyl-containing polymers may be effected by means of 9-anthryldiazomethane (compound II in scheme (2)) [10]. The reaction of compound II with COOH groups of the macromolecules (scheme (2)) takes place rapidly and under mild conditions (with low concentrations of the reactants, at room temperature, in the absence of catalysts), which means that this reaction may be used even for quantitative determination of carboxyl groups when their amount in polymers is very low (less than 0.1 °/o) [1 1]. With the aid of compound II it is therefore possible to add 9-alkylanthracene groups not only to copolymers of N-vinylamides with acrylic, methacrylic, crotonic and other unsaturated carboxylic acids, but also to (co)polymers containing a labelling number of carboxyl groups (~0.1 mole ~/~).The latter case is essentially the way in which homopoly-N-vinyl amides containing luminescent labels are prepared. c HN., N/~/\,J

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To get a labelling amount of COOH groups into the polymer chains of N vinylamides during polymerization processes it is advisable that the carboxyl-containing comonomer should be protonic acid, as in this case (in contradistinction, for instance, to acrylic or methacrylic acids) polymers with a sufficiently even distribution of carboxyl groups will be formed [2]. To obtain a labelled poly-N-vinylpyrrolidone it is also possible to use the reaction of compound II with carboxyl-containing units of N-vinyl-?-aminobutyric acid which are formed during hydrolysis of poly-N-vinylpyrrolidone units accompanying polymerization of N-vinylpyrrolidone in aqueous solutions [2].

Addition of anthracene-containing luminescent groups to N-vinylamide (co)polymers containing hydroxyl or amino groups. 9-Anthrylmethylsocyanate (compound IV, scheme (3)) is a suitable reactant for the addition of luminescent labels to various aminoor hydroxyl-containing (co)polymers of N-vinylamides. With the aid of compound IV one is able to add anthracene-containing labels not only to copolymers based on N-vinylamides (such as copolymers of N-vinylpyrrolidone with a vinylamine [5, 12], with a vinyl alcohol [2], or with an aUyl alcohol [13]), but also to hydroxyl endgroups

672

M. G. KRAKOVYAKet al.

of homopolymers of N-vinylamides obtained, for instance, by polymerization in aqueous media initiated by hydrogen peroxide [4]. In the latter case the location of luminescent anthracene groups just at the ends of the polymer chains is borne out by their dynamic characteristics determined by the polarized luminescence method.

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Absorption spectra for solutions in methanol: 1-copolymer of N-vinylpyrrolidone and acrolein (14.5 mole 9/oo)with anthracene-containing groups of type VIII, cp= 2.8 mg/ml; 2 - t h e same copolymer after sodium boron hydride treatment (compound IX), cp=2.6 mg/ml. The pointers show the absorption band peaks at 376 (1) and 369 nm (2).

Addition of anthracene-containing luminescent groups to copolymers based on N-vinylamides containing aldehyde groups. Copolymers based on N-vinylamides containing aldehyde groups (copolymers of N-vinylpyrrolidone with acrolein or crotonic aldehyde) are capable of fo~ming covalent bonds with amino-containing compounds o f a low

Polymers and copolymers based on N-vinylamidcs

473

molecular weight or polymeric nature, and are used to modi[v biologically active substances (BAS) [2, 6, 15, 16]. The interaction of amino-groups of BAS with aldehyde result in the formation of azomethine bonds which, on subsequent reduction with sodium boron hydride may be transformed into saturated N - - C bonds ('flee aldehyde. groups are in this case transformed into OH groups) [16]. To add luminescent 9-alkylanthracene groups to aid:hyde-containing copolymcr~ it is advisable to use an anthracene-containing amine, such as (for instance) 9-anthrylmethylamine (compound VII, scheme (4)). Azomethine bonds of groups VIII formed when compound VII reacts with aldehyde groups are stable in an aqueous sohttioa of the copolymer, at least for several days. This is evident from the data obtain .~d by the polarized luminescence method that is sensitive to the appearance of low molecular weight luminescent compounds in solutions of labelled polymers [9]. N-vin3lamide copolymers containing aldehyde groups having labels of type VIII may be used for the addition of BAS. Treatmet of polymer systems containing groups of type VIII with sodium boron hydride leads to the formation of stable luminescent labels of type IX. Transformation of VIII to IX is corroborated by the following facts: there is a change in the absorption spectrum of the labelled copolymer (see Figure) and a change m ~tle value of 1/P o [8, 9] characterizing the amplitude of high-frequency movements of the luminescent group added to the polymer chain (in aqueous solutions of the N-vinylpyrrolidone-acrolcin copolymer the value changes from 9.0 for group VIII to 15-0 for IX). The amount of 9-alkylanthracene groups in the copolymer remains practically constant during its treatment with sodium boron hydride

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Optical and dynamic properties of the anthracene-containing groups m polymer:, prepared by the methods indicated meet all the requirements in respect to luminescent labels in polymer systems that must be satisfied when the polarized iuminc~cence method is going to be used. After their reaction with the anthracene-containing reactants the N-vinylamide (co)polymers were painstakingly purified, using adsorption-chromatographic methods, ultrafiltration or repeated reprecipitations. The polarized luminescence method was used to ensure that all low molecular weight luminescent impurities had been completely removed from the labelled polymers [7-91. The method of UV-analysis was used to determine amounts of added 9-alkylanthracene groups in the polymer systems. We will now give some examples of methods used to prepare (co)polymers of N-vinylamides containing luminescent anthracene-containing groups, as follows.

674

M . G . KRAKOVYAKet al.

Poly-N-vinylamides. Poly-N-vinylcaprolactam. Copolymerization of N-vinylcaprolactam with crotonic acid (molar ratio 500 : 1) was conducted in an argon atmosphere in sealed ampoules (with D M F as solvent, concentration of monomers 56 %, concentration of azoisodibutyronitrile 0.25 %) at 60° for 20 hr. The (co)polymer was precipitated from the reaction solution with ether, 95 % conversion, ~rv = 60,000. To a solution of 500 mg of the obtained (co)polymer in 2 ml of purified toluene was added dropwise a solution of 5 mg of 9-anthryldiazomethane [10] in 0.25 ml of toluene. The reaction was run for 24 hr at room temperature, the purified poly-N-vinylcaprolactam contained 0.17 mole % of 9-anthrylmethylcalboxylate groups. Poly-N-vinylpyrrolidone and poly-N-methyl-N-vinylacetamide containing labels of the 9-anthrylmethylcrotonate structure were prepared by a similar method. Poly-N-vinylpyrrolidone. To a solution of 110 mg of commercial grade poly-N-vinylpyrrolidone for medicinal use with M = 12,000 (prepared by polymerization in an aqueous solution with hydrogen peroxide as the initiator) and containing units of N-vinyl-~-aminobutyric acid in 1 ml of methanol was added, whilst stirring, at room temperature a solution of 2 mg of 9-anthryldiazomethane in 0.2 ml of dioxan. After 2 hr the polymer was precipitated with ether. The purified poly-N-vinylpyrrolidone contained 0.06 mole % added 9-alkylanthracene groups. A control test tun on poly-N-vinylpyrrolidone synthesized by polymerization in D M F (with AIBN as the initiator) resulted in a polymer containing only anthracene group per 6-7 thousand polymer units (~0.01 mole%). Poly-N-vinylpyrrolidone with labels at the chain ends. To a solution of 250 mg of poly-N-vinylpyrrolidone for medicinal use containing OH end-groups in 1.5 ml of chloroform was added at 55 ° a solution of 20 mg of 9-anthrylmethylisocyanate [14] in 0.5 ml of chloroform. The reaction was run for 3 hr at 55 °, the polymer was then separated by precipitation with ether. The purified polymer contained 0.36 mole % 9-anthrylmethylcarbamate groups. N-vinyl amide copolymers. The copolymer of N-vinylpyrrolidone with crotonic acid (23 mole %). To a solution of 100 mg of copolymer in 1 ml of methanol was added, at room temperature, a solution of 1 mg of 9-anthyldiazomethane in 0.2 ml of dioxan. Upon precipitation after 2 hr the purified copolymer contained 0.14 mole % 9-anthrylmethylcarboxylate groups. Copolymer of N-vinylpyrrolidone with vinylamine (9 mole %) [ 12]. A solution of 295 mg of the copolymer in 20 mg of 9-anthrylmethylisocyanate in 26 ml of DMAA was stirred for 4 hr at 25 °. After the reaction the purified copolymer contained 0.15 mole % 9-anthrylmethylurethane groups. Copolymer of N-vinylpyrrolidone and allylalcohol (14"5 mole %) [13]. A solution of 200 mg of the copolymer and 0.6 mg of 9-anthrylmethylisocyanate in 1 ml of chloroform was stirred for 4 hr at 55 °, after which the copolymer was precipitated with diethyl ether. The number of 9-anthrylmethylcarbamate groups in the purified copolymer amounted to 0.06 mole %. Copolymer of N-vinylpyrrolidone and acrolein (10 mole%) [15]. A solution of 200 nag of the copolymer and 1 mg of 9-anthrylmethylamine [17] in 1 ml of D MF was heated for 5 hr at 50°. The amount of anthracene-containing azomethine groups VIII (scheme (4)) in the copolymer after separation and purification amounted to 0"16 mole % after the reaction. After sodium boron hydride treatment [16] of an aqueous solution of the labelled copolymer prepared by the above-described method (scheme (4)) there was scarcely any change in the amount of anthracene-containing units (IX) in the copolymer.

Translated by R. J. A. HENDRY REFERENCES 1. D. H. LORENZ, Encyclopedia of Polymer Sci. and Technology (Eds. H. F. Mark and N. G. Gaylord). vol. 14, p. 239, ~l.Y.-London-Sydney-Toronto, 1971 2. F. P. SIDEL'KOVSKAYA, Khimiya ~l-vinylpirrolidona i ego polimerov (Chemistry of N-vinylpyrrolidone and its Polymers). Moscow, 1970 3. Yu. E. KIRSH and L. V. SOKOLOV, Khim.-farm. zhurn. 17: 711, 1983

Interfacial interactions in extensively filled polystyrene

675

4. F. HAAF, A. SANNER and F. STRAUB, Polymer J. 17: 143, 1985 5. M. V. SOLOVSKY, E. V. ANUFRIEVA, E. F. PANARIN, V. D. PAUTOV and G. E. AFINOGENOV, Makromolek. Chem. 183: 1775, 1982 6. T. B. TENNIKOVA, Ye. F. PANARIN, O. A. MIRGORODSKAYA, G. V. SAMSONOV and B. V. MOSKVICHEV, Khim.-farm. zhurn. 11: 86, 1977 7. Ye. V. ANUFRIEVA, Sovremennyye fizicheskiye metody issledovaniya polimerov (Present-day Physical Methods used in Polymer Research). p. 77, Moscow, 1982 8. E. V. ANUFRIEVA, Pure and Appl. Chem. 54: 533, 1982 9. E. V. ANUFRIEVA and Y. Y. GOTLIB, Advances Polymer Sci. 40: I, 1981 10. M. G. KRAKOVYAK, E. V. ANUFRIEVA, V. B. LUSCHCHIC, N. S. SHELEKHOV and S. S. SKOROKHODOV, J. Macromolec. Sci. Chem. 12: 789, 1978 11. V. B. LUSHCHIK, M. G. KRAKOVYAK and S. S. SKOROKHODOV, Vysokomol. soyed. A22: 1904, 1980 (Translated in Polymer Sci. U.S.S.R. 22: 8, 2091, 1980) 12. R. I. GRUZ, T. Yu. VERKHOGLYADOVA, Ye. F. PANARIN and S. N. USHAKOV, Vysokotool. soyed. A13: 647, 1971 (Translated in Polymer Sci. U.S.S.R. 13: 3, 736, 1971) 13. T. B. AN1KINA, Ye. F. PANARIN, K. K. KALNIN'SH and B. V. MOSKVICHEV, Vysokomol. soyed. BI8: 196, 1976, (Not translated in Polymer Sci. U.S.S.R.) 14. M. G. KRAKOVYAK, V. B. LUSHCHIK, Ye. A. SYCHEVA and Ye. V. ANUFRIEVA, Vysokomol. soyed. B28: 289, 1986, (Not translated in Polymer Sci. U.S.S.R.) 15. Ye. F. PANARIN, I. L GAVRILOVA and V. V. NESTEROV, Vysokomol. soyed. B20: 66, 1978, (Not translated in Polymer Sci. U.S.S.R.) 16. T. M. TARATINA and B. V. MOSKVICHEV, Khim.-farm. zhurn. 19: 31, 1985 17. R. CALAS, R. LALANDE, J.-G. FAUGERE and F. MONLINES, Bull. Soc. Chim. France, No. 1, 119, 1965

Polymer Science U.S.S.R. Vol. 29, No, 3, pp. 675-682, 1987 Printed in Poland

0032-3950/87 $I0.00+.00 1988 Pergamon Press pie

ENERGY OF INTERFACIAL INTERACTIONS IN EXTENSIVELY FILLED POLYSTYRENE* Y'u. S. LIPATOV, G. V. TITOV, S. S. DF,MCHENKO

and V. P. PRIVALKO Institute of Macromolecular Chemistry, Ukr. S.S.R. Academy of Sciences

(Received 5 August 1985) Heat effects accompanying the interaction of atactic polystyrene with'methylene chloride were measured at 303 K. The polymer contained up to 80 wt. ~ of non-modified Aerosil and was prepared by evaporating the solvent from dilute solutions in cyclohexane or in benzene. The conformation of macromolecules was found to be more compact in the former than in the latter case. A full development of interfacial interactions polymer-filler, corresponding to a situation where all polymer chains are localized in the adsorbed layer, depends on the character of the solvent and on polymer molecular weight. Polystyrene chains in the adsorbed Vysokomol. soyed. A29: No. 3, 604-610, 1987.