The polymerization of aminoesters and their salts in various solvents

106

YE. V. BU~E et al.

latter in HMS melts. The proposed equations are analytical functions, not containing correlation constants and permit determination of ziziS~_t according to the molecular data for low MW substances and EU in HMS, within the framework of the theory of corresponding states for organic low MW liquids. Translated by C. W . CAPP REFERENCES 1. A. Ire. NESTEROV a n d Yu. S. LIPATOV, Obrashehennaya gazovaya khromatografia v termodinamike polimerov (Applications of Gas Chromatography in Polymer Thermo. dynamics), p. 128, Kiev, l~aukova dumka, 1976 2. D. L. MEEN, F. MORRIS, J. H. PURNELL and O. P. SRIVASTAVA, J. Chem. See. Farad. Trans. 69: 2080, 1973 3. J. H. HILDEBRAND, J. M. PRAVSNITZ and R. L. SCOTT, Regular and Related Solutions, p. 12, Princeton, Van Nostrand-Reinhold, 1970 4, A. A. MIROSHNICHENKO, Vysokomol. soyed. A24: 2334, 1982 (Translated in Polymer 'Sci. U.S.S.R. 24: 11, 2678, 1982) 5, O. OLABISI a n d R. SIMMA, Macromolecules 8: 211, 1975 6. R. RIDD and T. SHERWOODp Svoistva gasov i zhidkosbei (Properties of Gases a n d Liquids). p. 110, Khimiya, 1971 7. A. A. TALER, Fisikokhimia polimerov (Physical Chemistry of Polymers). p. 261, Khimiya, 1978 8. O. A. OSIPOV, V. I. MINKIN and A. D. GARKOVSKII, Spravoehnik po dipolnim moment.am (Handbook of Dipole Moments). p. 114, Vysshaya shkola, 1971

Polymer Science U.S.S.1L Vol. 25, No. 1, pp. 106-113, 1983 :Printed in Poland

0032-3950/83 $10.00+.0 © 1983 Pergamon Press Ltd.

T H E P O L Y M E R I Z A T I O N OF A M I N O E S T E R S A N D T H E I R SALTS IN V A R I O U S SOLVENTS* Y]~. V. BUNE, A. P. S~EINKER, A. L. IZYU~NIKOV, YE. D. ROOOZHKINA and A. D. ABKI~ L. Ya. Karpov Physico-Chemical Research Institute

(Received 28 J u l y 1981) The elementary rate constants of propagation and termination for the polymerization of diethylaminoethyl methaerylate (DE) and its acetate and hydroehioride salts in various solvents have been determined. The correlation between the polymerization rate of DE acetate in dioxane-water mixtures of various compositions and the position ~of the re, o frequencies of the monomer in those solvents was found. The increase in * Vys0komol, soyed. A25: No. 1, 93-99. 1983.

Polymerization of aminoesters

107

the rate of polymerization of D E and of its salts with its transfer from the organic solvents to water is a result of the formation of a hydrogen bond between the C = O group of the monomer and the solvent. The different conformations of the growing polymer chains due to a change in the degree of ionization of these monomers in solvents of different type also makes an essential contribution to the change in polymerization rate.

T~E nature of the medium has a pal%icularly strong influence on the polymerization of ionizable monomers in solution. Thus in references [1-5] a higher rate of polymerization of aminoesters and their salts was found in aqueous-organic mixtures and in water compared with that in organic solvents. We have shown, in a study of the polymerization of diethylaminoethyl methacrylate (DE) and its acetate (DE-I) and hydrochloride (DE-2) salts in various solvents*, that the polymerization rate is increased oa adding water to the organic solvent (Table 1). TABLE

i. M-4.0:IW[TUDE

OF ~p A N D

k o IN T H E

POLYIVLERIZATION

VARIOUS SOLVENTS

Mono-I [M]I mer mole i .

Solvent

[DAA] × × 103, mole/1.

iT

v X 105

OF

DE, DE-1

AND

DE-2 iN

25 °

! v~× 105

mole/1. •see

kp×

10-a

[ k 0 × 1 0 -v

1./mole. scc

i

DE

I

DE-1

DE-2

Dioxane Dioxam~-water * Methanol 0.833 Dioxane Dioxane-watCr * Water O-5OO Methanol Methanolwater *

0.833

19'5 5"4 5-4 19"5 5-4 0"6

4.3±0"3 15"4±0"4 0.09±0.027 0.06±0.016 3.6±0-215.2±0.3 0.36~0.07 10.33-4-0.06 1"5±0"2 1"0±0"2 0.7±0-15 11-30±0.3 10"0±0"2 16-0±1"3 0.3+0.08 !0.1±0.03 8"9-[0'4 4.2±0'7 1.8±0.63 1.2±0.42 13"5±0"3 0 ' 3 3 ± 0 ' 0 2 72~=16 65±15

0'6

2"6±0"2

0-6

3'0±0"2

0"42±0"04 i

3.3±0.7

0"37±0-04 10-8±2

0.9±0.2 6 ± 1.2

* W a t e r c o n t e n t ca. az"O+/o.

The higher polymerization rate in aqueous organic mixtures and iu water was explained b y the authors of [1, 2, 5] mainly as duo to a decrease in the rate of chain termination by vil%ue of electrostatic interactions, conformational effects and others. As is evident from Table 1, the observed mechanisms of monomer polymerization b y cationic means are indicated b y the increase in kp and not b y a decrease in k0, as was suggested earlier; k 0 as with kp, increases in the transfer from organic solvents to water. In our opinion, the dependence of the different rates of polymerization of aminoesters and their salts on solvent nature is duo to a series of reasons. One of those is the change of radical reactivity in monomers due to coupling of C z C and C = O bonds, forming hydrogen bonds between the * The methods of polymerization and determining the elementary rate constans for propagation and t e r m i n a t i o n axe given in [6].

108

YE. V. BUNE et a l .

C = O groups of t h e monomer and the solvent. Earlier On, in [7], t o explain the higher rates o f acrylamide polymerization in water in comparison With' other solvents, it was Suggested t h a t the increase in acrylamido r a s c a l reactivitylwas due to addition to it of a proton at the C = O bond. The strength of interaction of the solvent with the C = O group may be judged from the change in frequency of the valency oscillation of the C = O in the I R spectra. In this connection, we changed the i frequency rc=o for DE-1 in various solvents and measured the polymerization rate in them. I t was found t h a t vc=o was decreased by transfer from dioxane and acetonitrile to the mixed solvent, dioxane-water and to water; which indicates t h e formation of an H-complex between the C---~O group of the monomer and the solvent. A comparison of the polymerization rates With frequencies, vc=o for DE-1 showed that these parameters, as would be expected correlate mutually (Fig. 1). The existence of such a correlation permits consideration of the specific interaction of the monomer with the solvent, forming an H-complex, as one of the factors influencing the change in electron density at the C ~ C double bond in the monomer, forming a radical from it and therefore affecting its reactivity. The change in electronic structure of DE and its salts with changing nature of the solvent can also be forseen from the UV spectra of the monomers. The large intensity of the absorption band (e-1041./mole.cm) (see Table 2) indicates a g-g* transition, by a definite coupling of C = C and C ~ O groups (see Table 2) a n d the observed shift of the absorption maximum in the long wave region with ~-~* transfer indicates the formation of hydrogen bonds with the solvent [8]. For a confirmation of the ideas on a mutual commction of the position of the frequency vc=o of the monomer with polymerization rate, we also examined the kinetic data for other monomers, available in the literature. I n this case, we found a correlation between polymerization rates, magnitudes of ko/k ~ and rc=o i~ TABLE 2. THE EFFECTOF S()I.VI.;NTNATUI~EON POSITIO2qOF ABSORPTION BaND I~" UV SrECTRA OF DE, DE-I aND DE-2 Monomer DE

DE-I

DE-2

Solvent Cyclohoxanc Methanol Methanol-HzO (1 : 1) Water Cyclohcxane Methanol Motlmnol--FIgO (1 : 1) Water Methanol Methanol-Hie (1 : 1) Water

2max,

nm

[

~ × 10',

] l./mole, cm

200.5 203 2O5 210 201 205

i I i ! II

1.15 1.24 0.86 0.92 0.96 1.10

208 209.5 204 206 210

! I I , ~

0.84 0-78 1.06 0.91 0-94

Polymerization o f aminoesters

109

different solvents*. Figure 2 shows the corresponding results for aerylamide [10, 11], N - v i n y l p y r r o l i d o n e [!2], D E , d i m e t h y l a m i n o e t h y l m e t h a e r y l a t e (DM), t h e i r q u a t e r n a r y salts w i t h e t h y l b r o m i d e ( D E - 3 , DM-3) a n d t h e h y d r o b r o m i d e ( D E - 4 ) [3, 4]. A s e v i d e n t f r o m Fig. 2, t h e r a t e o f p o l y m e r i z a t i o n a n d t h e r a t i o kp/k~o f o r v a r i o u s m o n o m e r s a r e l i n e a r l y r e l a t e d t o vc=o f o r t h e m o n o m e r . A n V ,/O~mole/L.sec

6

5

q 2 f

I

17.2

17.1

~10"2cm

C=O

FIe. 1. Correlations between polymerization rate of DE-1 and frequency Vc=o of the monomer in various solvents: 1 -- aeetonitrile; 2-- dioxane; 3 -- dioxane containing 30, 4 -- 50, 5 -- 70 and 6--97 mole~o water.

u~rnole/i..#ec L

/1II

b

I °l

9 7 = 1,1'

7

xlI "1li 5"oly" mY" oYI J +y#

5 3

1 , x~"c,-"/~L/J

17"I

I

IB'9

=

I6"7

17"1 VC=0 ,, 10~ cm "I

18.9

18.7

FIG. 2. Correlations between kp/k*0 (a), polymerization rate (b) and frequencies %-o of aerylamide according to data of [9], (I), and [!0] (I'), N-vinylpyrrolidone [12] (II), DE-3 (III), DM-3 (IV) and DE- 4 (V), D E (VI) and DM (VII) [3, 4] in water (1), in DMSO (2), in the T H F (3), in methanol (4), in dioxane (5), in acetonitrile (6) and in ethanol (7)" * The frequencies rc= o for aelTIamide in water methanol, T H F and acetonitrile were determined by us and Vc=o in DMSO and in dioxane were tak6n fr6m [9]. I n the absence of this da~a for D E - 3 and DM-3, we used for these the data we measured for D E - 1 ~nd DM-I:

110

YE. V. BUNE e~ a/.

interrelation was noted between the polymerization rates and the frequencies vc=o for cyclohexyl-, cyclododecylacrylates [13] and ~-vinylpyrrolidone [14]. The rate increase in protonic solvents [14] was explained by hydrogen bonding between the C=O group of N-vinyl]~yrrolidone and the solvent which, in the authors' opinion, causes an increase in monomer sctivity. As a matter of fact, such solvation increases radical activity, which explains the increased polymerization rates. Thus the combinatiolt of our results with those in the literature confirms the idea that the influence of solvent nature on polymerization rate is in the first place linked with the change in reactivity of monomers and their radicals, due to changing degrees of C = O, C:C-linking in monomer-solvent interactions. A suggestion was made in [3, 4], that the higher polymerization rate in water, compared with that in organic solvents is connected with specific monomer hydration. The authors of [3, 4] however, do not discuss why such hydration causes the rate increase. b-

u , lO, mo/e/L.~ec 8

q 2 0

i

I

I

I

I

20

gO

60

80

I.o0

~IG. 3. C o r r e l a t i o n s b e t w e e n p o l y m e r i z a t i o n raft, a n d i o n - p a i r conLent (IP) for DI@-I in a wa~er-dioxa~m m i x t u r e .

We have shown earlier [15], that aminoester salts exist in solution, depending on the type of solvent, as molecular complexes, ionic pairs and free ions. It has been found that polymerization rate correlate.s with the quantity of ion pairs of the salt (Fig. 3). The existence of such a correlation evidently is explained by the fact that ability to form hydrogen bonds and ionising strength of a solvent change symbatieally [16]. A different conformation of the growing polymer chains introduces an essential contribution to the polymerization rate change due to the change in ionization degree of these monomers in solvents of different types. I t was shown in [6] that the relative viscosity of solutions of polymer and monomer of DE-1 and therefore the sizes of the polymer globule are increased as the quantity of water in the dioxane-water mixture increases. The positive charges of the monomer units of the salt in the growing macromolecule facilitate chain straightening, which evi-

Polymerization of aminoesters

111

dently, must help to increase reaction because o f decreased Steric hindrance. Methanol, having a high ionizing power [16], occupies a special place amongst organic solvents. The number of ionized monomer salt molecules in methanol amounts to more than 50~/o. Therefore in methanol, as in water, DE-2 has a polyeleetrolyte effect. In water, where the salt molecules are fully ionizedi the characteristic viscosity of DE-2 polymer is notably higher than in methanol; however, on adding monomer to the solution, the viscosity in both solvents decreases and in proportion to its increase in concentration in solution, t,he viscosities in water and methanol are observed to approach one another. With a monomer concentration of 0.5 molefl.* a n d above, the viscosities of solutions of DE-2 polymer in those solvents are practically identical, therefore the g r o ~ n g macromolecules have coils of similar size. Consequently, it is probable that with the transfer from methanol to water, the polymerization rate is changed only 3-6 times, whereas it is 9 times for a transfer from dioxane to water. These results indicate the smaller contribution of changes in conformation of the growing macromolecule with transfer from polymerization in methanol to that in water. I t should be kept in mind that viscometric measurements are carried out with "dead" polymer. In a polymerizing system at the moment of chain growth, when the equilibrium state of the: macr0molecule in the solution has not been established, the conformational differences fox' a growing radical in water and methanol m a y apparently be greater than for "dead" polymer. I t has been suggested in some referenees [17, 18] that the increase in kp ~ith polymerization of ionizable monomers m a y be connected with the growth of local monomer concentration in the bulk of the growing macroradical. We carried out a study of adsorption of DE and DE-2 b y the corresponding polymer b y the photodiffusion method [19] in various solvents (dioxane, methanol ~md methanol containing 5 and 10% water) and have shown that monomer concent,rations in solution and in the polymer coil are practically identical. Thus ~he increase in the polymerization rate of aminocsters and their salts on addillg water to the organic solvent is not connected with growth ofl a local mono:,~mr concentration in the bulk of the growing macroradical. There is a basis for considering that the different conformation of the growing macroradicals of aminoesters and their salts in solution is a reason for the much higher polymerization rate of the salts, compared with the aminoesters [6]. Data on the characteristic viscosity of these polymers in methanol in presence of LiC1 supports the difference in conformational state. The characteristic viscosities of DE-2 and D E polymers of the same MW, prepared under different conditions, differ b y ca 1.7 times ~. These results indicate the more developed eonformatiou of the macromolecules of the salt i n comparison with those of the aminoester, which are explained b y the much higher polymerization rate of the salts for the reasons given above. The more favourable conformation of the salt macrora~lical to t h e * The polymerization of DE-2 was studied at a concentration of 0.5 mole/1.

]=12

YE. V. Burr: et al.

s t e p s o f c h a i n g r o w t h is explained b y t h e presence t h e r e i n of i o n p a i r s a n d free ions a n d results in large kp values for t h e salts c o m p a r e d w i t h t h a t for t h e a m i n o ester. So lop for D E - 1 in d i o x a n e is ca. 3 t i m e s a n d for D E - 2 in m e t h a n o l is ca. 5 t i m e s greater, t h a n for D E in these solvents (Table 1). I t is n o t possible to explain t h e differences in p o l y m e r i z a t i o n r a t e s of a m i n o e s t e r s a n d t h e i r salts b y t h e different degrees of coupling of C-~C a n d C ~ O b o n d s ~ f these m o n o m e r s . F o r t h e s a m e degree of coupling, t h e r e are close v a l u e s o f t h e f r e q u e n c y vcffio in t h e I R s p e c t r a of a m h l o e s t e r s a n d salts in t h e c o r r e s p o n d i n g solvents. T h u s for e x a m p l e , vc=o in d i o x a n e for D E is 1719 cm -1 a n d for D E - 2 it is 1721 c m - L T h e U V d a t a also show t h a t the degrees of coupling for t h e D E a n d its salts are similar, since t h e positions of t h e a b s o r p t i o n b a n d ~max for D E a n d t h e salts D E - 1 a n d D E - 2 (Table 2) p r a c t i c a l l y coincide. Therefore, t h e differe n t reactivities of a n aminoester, its salts a n d the corresponding radicals in t h e s a m e solvent are d e t e r m i n e d m a i n l y b y t h e different c o n f o r m a t i o n s of t h e growing m a c r o r a d i c a l s of these m o n o m e r s because of their different degrees of ionization. Translated

by C. W. CArP

1. E. I. ABIAAKIMOV, R. K. GAVL~RINA and N. K. $HAKALOVA, v kn: Reakstiormaya sposobnost' organicheskikh soyedenenii (in book: Reactivity of Organic Compounds). Tartu, Izd. Tartovskovo unta 4: 838, 1967 2. R, V. YEGOLYKN, L. M. GALSTYAN and N. M. BEILERYAN, Arm. khim. zh. 82: 520, 1979 3. A. I. MARTINENKO, R. RUSTSEV, A. V. NECHAYEVA, A. T. DZH.ALI~.OV, D. A.

TOPC/HYEV and V. A. KABANOV, Uzb. Khim. zh., 59, 1979 4. A. I. MARTINENKO, Avtoref. dis. na soiskaniye uch. st. kand. khim, nauk. (Dissertion, canditate in chemical science). 1NKhS, U.S.S.R. Academy of Sciences, p. 24, 1981 5. N. N. LOGINOVA, Avtoref. dis. na soiskaniye uch. st. kand. khim. nauk (Dissertion, candidate in chemical science). LT1 im. Lensoveta, p. 19, 1969 6. E, V. BUNE, A. P. SHEINKER, N. V. KOZLOVA and A. D. ABKIN, Vysokomol. soyed. A28: 1841, 1981 (Translated in Polymer Sci. U.S.S.R. 28: 8, 2019, 1981) 7. V, F. GROMOV, Dis. na soiskaniyo uch. st. kand. khim. nauk. (Disscrtion, candidate in chemical science). N I F K h l im L. Ya. Karpov, p. 138, 1969 8. O. V. SVERDLOVA, Elektronniye spektri v organicheskoi khimiJ (Electronic Spectra in Organic Chemistry). p. 218, Khimiya, 1973 9. L. M. MINSK, C. KOTLARCHIK and R. S. DAR,LA]K. J. Polymer Sci., Polymer Chem. Ed. 11: 353, 1973 I0. V, F. GROMOV, N. I. GALPERINA, T. O. OSMANOV; P. M. KHOMLINSKII and A. D. ABKIN, Europ: Polymer J. 16: 529, 1980 I I. A. CHAPmO amd,L. PI~I~EC,8PRJTZFAt,: Et~rgp. Polymo~ J. 11:59, 1975 12. I. I. GAL'pERINA, V. F. GROMOV~ P. M. KHOM!KOVSKII,.A.D. ABKIN and Ye.,N. ZAV'YALOVA, Vysokomol~ soyed. BI6: 21~7, 197~t (Not ~ranslated m Polymer ~cl. U.S.S.R.) 13. A. D A l t O N anti J. iK. liL~MANOTAN~,,J. Maicrorno~. ~hem.. |76: 2~59, ~9"[5r. 14. Ya. KIRSH, A. I. KOKORIN, T. M. KARAPUTADZE and L. A. KAZARIN, Vysokomol. soyod. B ~ : 444~ 1981 (Not traz~slatod isa P(Jlymer SoL:U.S.S.r.)•

•

.

,

.

,

.

R ad i at io n impulse induced electrical conductivity of aromatic P I

113

15. A. P. SHEINKER, N. V. KOZLOVA, Yc. V. BUNE and A. D. ABKIN, Doklad. Akad. N a u k SSSR 258: 953, 1981 16. A. S. DNEPROVSKII and T. L TElVINIKOVA, Teoreticheskiye osnovi organicheskoi khimii (Theoretical Basis of Organic Chemistry). p. 229, Khimiya, 1979 17. V. A. KABANOV and D. A. TOPCHIYEV, Polimerizatsiya ionizuyushchikhsiya monomeroy (Polymerization of Ionizing Monomers). p. 16, Nauka, 1975 18. D. A. TOPCHIYEV, L. A. MIRTCHYAN and V. A. BAKANOV, Doklad. Akad. Nauk SSSR 226: 883, 1976 19. V. E. ESKIN, Rasseyaniye sveta rastvorami polimerov (Diffusion of Light by Polymer Solutions). p. 193, Nauka, 1973

Polymer Science U.S.S.R. Vol. 25, No. 1, pp. 113-122, 1983 Printed in Poland

0032-3950/83 $10.004-.00 © 1983 Pergamon Press Ltd.

RADIATION IMPULSE INDUCED ELECTRICAL CONDUCTIVITY OF AROMATIC POLYIMIDES WITH DIANHYDRIDE COMPONENTS OF DIFFERING STRUCTURE * A. P. TYUT~EV, V, S. SAYENKO,V. S. TIKHOMIROV and Y~. D. POZ~IDAYEV "Plastmassy"

Production Dept, Moscow Mechanical Engineering Institute

(Received 28 July

1981)

The induced electrical conductivity of aromatic polyimides, based on diaminodiphenyl ether dianhydride components of different structures, was studied over a wide range of parameters of impulsed radiation in a v a c u u m (2 × 10 -a Pa), at room temperature. A sharp increase in the residual electrical conductivity of polypyromellitic imide, irradiated in a v a c u u m with doses of 105-10 ~ G-r was confirmed, which is related to radiation induced modification of the polymer structure. The structure which is formed has a metastable character and is easily degraded in the presence of oxygen.

THE question of induced electrical conductivity by impulsed radiation of polyimides (PI), being indisputably important for their use as dielectrics and electrical insulating materials, has only been brought to light in a few articles [1-3]. As a rule, the data presented in the literature have been obtained for a P I which is the product of polycondansation of diaminodiphenyl ether and pyromellitic dianhydride, known in the U.S.S.R. as polyimide PM-1, "Kapton" (or N-film). It has also been shown [4] that the behaviour of PIs, differing in dianhydride component structure, continuously irradiated with large doses ( 1>105 G-r), is sharply changed. * Vysokomol. soyed. A25: No. 1, 99-106, 1983.