synthesis and microstructure of polymers from o-methacryloyloxybenzoic acid

Synthesis and Microstructure of Polymers from o-Methacryloyloxybenzoic Acid

J. SAN ROMAN, E. L. MADRUGA, and L. PARGADA, lnstituto de Phticos y Caucho, C.S.I.C., Juan de la Cierva 3,

28006 Madrid, Spain

Synopsis

The free radical polymerization of o-methacryloyloxybenzoic acid using acetone and benzene as solvents, in the interval 3O-12O0C, is investigated. The polymerization in benzene has a precipitant character. However, when acetone is used as solvent, a t reaction temperatures higher than 6C-70°C, the polymerization deviates from the classic free radical mechanism and, beside the addition of monomer molecules to growing chain ends, the release of salicylic acid and the formation of cyclic anhydride structures of glutaric type in the main chain has been detected. The microstructure of polymers obtained has also been studied by the transformation into the corresponding poly(methy1 methacry1ate)s.

INTRODUCTION

It has been widely recognized that high molecular weight polymers with specific functional groups are suitable in many of the applications of low molecular weight organic compounds and oligomers and offer advantages over the lower molecular weight materials.' This behavior is of particular interest in such properties as controlled polymer degradation or the release of active agents, which is of great importance in the use of polymers carrying biologi- cally active agents2

In this sense polymers have been synthesized with functional active groups in the main chain or as lateral substituents with effective applications such as c a t a l y ~ t , ~ . ~ UV drug and enzimatic supports,g-" etc. The use of derivatives of salicylic acid as UV absorbers is well known12 and several polymers prepared from salicylic acid and its derivatives are also known for their biological a ~ t i v i t y . ~ , * ~ * l4 Vinyl derivatives of salicylic acid have been synthesized and polymerized by Bailey and Vogl (7), but little attention has been paid to the synthesis and polymerization of acryloyl derivatives of salicylic acid, although the polymerization of p-acryloyloxybenzoic acid and p-methacryloyloxybenzoic acid has been studied by Blumstein et aL15 These monomers display crystallinity during the bulk polymerization at high temperatures or on casting of films from solution of the corresponding polymers.l6# 17Amerik et a1.18 have also studied the free radical polymerization of p-methacryioyloxybenzoic acid in different media. The incomplete conversion observed a t polymerization temperatures above 100°C in an isotropic medium was explained by these authors considering a polymerization-depoly- merization equilibrium. However, when the polymerization was carried out in a liquid crystalline phase, higher polymerization rates and molecular weights

Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 25, 203-214 (1987) 0 1987 John Wiley & Sons, Inc. CCC 0360-3676/87/010203-12$04.00

204 SAN R O ~ N , MADRUGA, AND PARGADA

were obtained, since the molecular structure of the mesomorphic phase creates favorable thermodynamic conditions for the formation of polymer molecules. On the other hand, the stereochemistry of polymers prepared in isotropic media was predominantly syndiotactic, the tacticity being slightly affected by the polymerization temperature.

However, the synthesis and polymerization of o-acryloyloxybenzoic acid and o-methacryloyloxybenzoic acid have received little attention. Only an article from Webr et al." describes a method of synthesis and polymerization, and in more recent papers,20,21 they study the free radical copolymerization of these monomers with comonomers containing tertiary amine groups in order to evaluate the effect of electrostatic interactions between the carboxylic and amino groups on the composition of copolymers.

Low molecular weight polymers ( M , 1800) prepared from o-methacryloyloxybenzoic acid seem to display antiinflamatory activity,lg and higher molecular weight polymers seem to display good properties as antiaggregating agents of platelets.22

In the present article we wish to describe an alternative synthesis of o-methacryloyloxybenzoic acid and the behavior of this acrylic monomer in the free radical polymerization in different media as well as the corresponding mechanisms of polymerization.

EXPERIMENTAL

Monomer Synthesis

o-Methacryloyloxybenzoic acid was prepared by the reaction of salicylic acid with methacryloylchloride using potassium carbonate as catalyst and acetone as solvent in the presence of a little amount of hydroquinone. In a typical experiment, a solution of salicylic acid (0.1 mol) and hydroquinone (0.005 mol) in acetone (150 mL) was placed in a three-necked flask provided with a stirrer, thermometer, and dropping funnel. To it was added potassium carbonate (0.1 mol), and the suspension was cooled to 0°C. Freshly distilled methacryloyl chloride (0.12 mol) was then added dropwise. After 2 h the solvent was distilled off a t reduced pressure, and the solid residue was added to a 5 w% solution of sodium bicarbonate. After neutralization with hydrochloric acid, the product was filtered, dried, and twofold crystallized with hot hexane (yield, 45%).

Polymerization Procedure

The monomer was polymerized at different temperatures from 30" to 120" in a thermostatic bath regulated with a precision of +0.loC, using 2,2'- azobisisobutyronitrile (AIBN) (111 = 0.3 mo196) and acetone or benzene as solvents ( I MI = 0.5 mol/L). All experiments were carried out in Pyrex glass ampules sealed off a t high vacuum. After the desired reaction time, the reaction mixture was added into hexane, and the precipitated polymer was filtered off, washed with hot hexane, and dried under vacuum until constant weight was attained.

POLYMERS FROM 0-METHACRYLOYLOXYBENZOIC ACID 205

Hydrolysis of p l y ( o-methacryloyloxybenzoic acid)

Hydrolysis was carried out in 1,4-dioxane with the potassium hydroxide/ methanol (20%) system a t 65°C for 24 h. The solution was added to ice water, and the precipitate was filtered, washed with hydrochloric acid, and dried in vacuum a t 50°C. Infrared spectrum of poly(methacrylic acid) in the form of solid film was checked up.

Esterification of poly(methacry1ic acid)

The poly(methacrylic acid) obtained from polymers was transformed to poly(methy1 methacrylate) according to the method of Katchalsky 23 by treating 0.3 g of dried poly(methacry1ic acid) with 50 mL of a benzene solution of diazomethane. The reaction mixture was kept standing overnight a t room temperature and then was added into excess of methanol. Crude poly(methy1 methacrylate) was purified by reprecipitation from benzene to methanol.

Polymer Characterization

All polymers were characterized by IR and NMR spectroscopies. IR spectra were recorded in KBr pellets or films on a Perkin Elmer 457 spectrometer a t room temperature. NMR spectra were recorded in deuterated acetone or chloroform solutions on a Varian XL-100 operating at 100 MHz, a t room temperature and 60°C, with TMS as an internal standard reference.

The molecular weight of poly(methy1 methacry1ate)s were determined by measuring the intrinsic viscosity in benzene solutions at 30 + 0.1"C. The equation given by Fox et al.'* for poly(methy1 methacrylate) unfractionated was applied.

RESULTS AND DISCUSSION

The free radical polymerization of o-methacryloyloxybenzoic acid has been carried out in acetone and benzene at polymerization temperatures ranging from 30" to 120°C. The concentrations of monomer and initiator (AIBN) were 0.5 mol/L and 0.3 mol% with respect to monomer, respectively. The results obtained are listed in Table I.

When acetone is used as solvent, high conversion and degrees of polymerization are obtained at polymerization temperatures lower than 8OoC, and a maximum value of the conversion-time ratio is reached for this solvent a t 60°C. However, if the polymerization temperature is higher than 80"C, a drastic decrease of both the polymer yield and polymerization degree is observed.

In the case of benzene, the polymer yield is higher than in acetone as a consequence of the precipitant character of the polymerization reaction. Poly( o-methacryloyloxybenzoic acid) precipitates in the reaction medium and, as has been widely recognized for polymerizations with precipitiation of the polymer in the reaction medium, the kinetic features can be described in terms of the diffusion-controlled reactions of polymeric radicals occluded in the highly viscous polymer.25 Logically, the diffusion of monomer or solvent molecules through the swollen polymer phase is possible, but diffusion of the growing macroradicals is strongly retarded if not hindered. Thus, the propa-

206 SAN ROMAN, MADRUGA, AND PARGADA

TABLE I Experimental Conditions and Conversion Degrees Free Radical Polymerization of

o-Methacryloyloxybenzoic Acid. I MI = 0.5 mol/L, I I I = 0.3 mol%

Conversion

__ T Reaction time weight Sample Solvent ("C) (h) DPn

A-30 Acetone 30 48 60 1002 A-60 Acetone 60 24 60 322 A-80 Acetone 80 18 20 243 A-100 Acetone 100 18 10 - A-120 Acetone 120 18 5 -

B-60 Benzene 60 24 B-80 Benzene 80 18

90 972 75 432

gation of the growing polymeric chains can continue i i thout restrictions, but the termination process is markedly reduced. The resultant effect is the increasing of the overall rate of polymerization as the growing radicals become incorporated into the swollen Also, the strong decrease of the termination process gives rise to the increase in molecular weight with respect to similar reactions in solution.

The difference in conversion degrees between the polymerization reactions a t the same temperature in both solvents, particularly a t 80°C and at a polymerization time of 18 hours, can be noted in Table I to be 75% in benzene and 20% in acetone. More drastic differences could be observed a t higher polymerization temperatures. This result scarcely would be explained by the precipitant character of the polymerization system in benzene. Thus, the drastic decrease in conversion degrees with an increase in temperature for the polymerization reactions in acetone suggests that the free radical polymerization of o-methacryloyloxybenzoic acid in solution a t temperatures higher than 60°C deviates from the classic free radical mechanism.

In order to study this behavior, the polymers obtained were analyzed by IR spectroscopy. The IR spectra of polymers prepared in acetone in the men- tioned range of polymerization temperatures (given in Fig. 1) show, among others, the typical carbonyl bands of methacrylic esters a t 1735 cm-' and aromatic acids a t 1690 cm-'. However, it can be clearly observed that the IR spectra of polymers prepared a t 80,100, and 120"C, show a well-defined signal centered a t 1800 cm-' whose intensity increases with the increasing of polymerization temperature; however, a t the same time the intensity of the carboxylic band a t 1690 cm-' decreases. Also, there is a considerable change of the shape of the spectra in the region 10oO-1100 cm-' in which can be observed the appearance of a rather intense signal a t 1020 cm-' for polymers prepared a t temperatures higher than 60°C.

In Figure 2 are given the optic density ratios for the signals of the ester group (1735 cm-') and the carboxylic group (1690 cm-') as well as the ratio for the signals a t 1735 cm-' and 1800 cm-'. The ratio A1735/A16w remains practically constant for polymers prepared at 30" and 60°C with a value very close to unity; however, a t higher temperatures it increases drastically with


0 krn-l)

IR spectra of poly(o-methacryloyloxybenzoic acid)s prepared in acetone at 30, 60, 80, Fig. 1. 100. and 12OOC.

the reaction temperature, whereas the ratio A,,,,/A,,, decreases progres- sively. The IR spectra of polymers obtained in benzene at 60°C, 80°C, or higher temperatures are very similar to those of the polymers prepared in acetone a t temperatures lower than 60°C, and any change of the carbonyl bands with the polymerization temperature is not observed, remaining practically constant for the ratio A1735/A1690.

By analyzing the origin of the IR signals a t 1800 and 1020 cm-', i t seems to be clear that they can be assigned with accuracy to anhydride groups. Results recently published by Butler and M a t s u m ~ t o ~ ~ for the radical polymerization of acrylic and methacrylic anhydrides indicate that the propagation step presents a complex mechanism considering that, beside to the monomer addition to growing radical ends, there is an intramolecular cyclation reaction that gives rise to the formation of cyclic anhydride groups in the macromolecular chains. The IR spectra of the corresponding polymers present absorption signals of anhydride groups a t 1800 and 1735 cm-l, similar to those of the poly( o-methacryloyloxybenzoic acid) prepared at temperatures higher than

208 SAN R O d N , MADRUGA, AND PARGADA

A m LO A 1600

4.0

3.0

2.0

1.0

LO 60 80 100 120 T. %.

Fig. 2. Variation of the optic density ratios of IR signals of poly( o-methacryloyloxybenzoic acid)s as a function of the polymerization temperature.

60-70°C. Moreover, the radical polymerization of acrylic and methacrylic anhydrides has been investigated in terms of cyclopolymerization by several a ~ t h o r s . ~ ~ - ~ ' The ring size of cyclic polyanhydrides depended on the solvent used and the polymerization temperature, 28 the formation of six-membered ring anhydride structures a t moderate temperatures being favored, although a relatively high content of five-membered ring anhydride units was also detected a t high temperatures, i.e., a t 115°C in solution.28

On the other hand, Matsumoto et al.31 have stated that the free radical polymerization of monoallyl phthalate initiated by benzoyl peroxide at temperatures of 70-90" C, presents a complex propagation mechanism by which, beside the addition of monomer units to polymeric growing radicals, can be produced a secondary reaction that gives rise to the release of phthalic anhydride and the formation of allylic alcohol units in the main chain. These authors have suggested that this behavior may be ascribed to the steric effect accompanying the release of the molecular complexity of growing chain ends by the dissociation of phthalic acid as is quite expected in terms of the molecular model.31

On these bases, according to the evolution of the carbonyl signals of IR spectra of polymers prepared a t 80, 100, and 120°C and taking into account that some little amount of salicylic acid has been isolated from the reaction medium as indicated by the corresponding IR spectrum, it is to be expected that the polymerization of o-methacryloyloxybenzoic acid deviates from the classic free radical polymerization mechanism when the reaction is c w e d out in solution a t moderately high temperatures. This mechanism is characterized by two reactions in the propagation step in which, beside the addition of monomer units to the polymeric chain ends, can be produced the elimination of salicylic acid, giving rise to the formation of anhydride groups in the macromolecular chains. The solubility of polymer samples prepared at any polymerization temperature and the position of carbonyl signals in the IR

POLYMERS FROM o-METHACRYLOYLOXYBENZOIC ACID 209

b- 6- E li mi not ion CHI CHL

c =o I I ?"3

+ Intromolrculor cyclotion 4 CH2- ; .+ cup'c'

I

0 / c \ o / C \ o

I wc& +

8"- Fig. 3. Propagation mechanism for the free radical polymerization of o-methacryloyloxyben-

zoic acid in acetone at temperatures higher than 60-70°C.

spectra (similar to those of the polyacrylic and methacrylic anhydrides) indicate that cyclic anhydride with the chemical structure of glutark anhydride32 is formed in the macromolecular chains by means of an intramolecular cyclation reaction in which two. consecutive monomeric units par- ticipate, according to the scheme of Figure 3.

The release of salicylic acid from the polymeric growing chains would explain satisfactorily the decrease of conversion degree and average molecular weight of polymers prepared at polymerization temperatures higher than 60-70°C, since the salicylic acid molecules in the reaction medium could act as a good transfer agent or even as an inhibitor compound.

On the other hand, the peculiar thermal behavior of poly( o-methacryloyloxybenzoic acid) supports this mechanism, since the thermogravimetric anal- ysis becomes apparent the release of salicylic acid a t moderated temperatures (130-140OC) and the formation of cyclic anhydrides of glutaric type structures in the macromolecular chains.33 Therefore, two ways of release of salicylic acid from the polymer chains can be suggested: one is as drawn in Figure 3, the reaction of elimination-cyclation of the active end of the growing chains, which probably will predominate a t moderate temperatures (70-80 O C), and the second one, the elimination-cyclation at any position along a com- pleted polymer chain, as a consequence of the thermal decomposition of an ester bond, which will predominate a t higher temperatures according to the thermal behavior of poly( o-methacryloyloxybenzoic acid).


TABLE I1 Detsrmination of the Molecular Weight of Poly(methy1 methacrylate)s, P(A - i) and

P( €3 - i), Prepared from the Original Poly( o-methacryloyloxy benzoic acid)s, (A - i) and (B - i) -

[TI MI2 an Sample (CC/P) P(A - i), P(B - i) (A - i),(B - i)

P(A - 30) 54.60 P(A - 60) 23.20 P(A - 80) 18.60

P(B - 60) 53.70 P(B - 80) 27.20

100,200 32,200 24,300

97,200 43,200

206,412 66,332 50,058

200,232 88,992

In order to study the microstructure and stereochemical configuration of polymers obtained, they were transformed into the corresponding poly(methy1 methacry1ate)s by means of the hydrolysis of poly( o-methacryloyloxybenzoic acid)s to poly(acry1ic acid)s using the potassium hydroxide/methanol system and methylation of the corresponding polyacids with diazomethane. The molecular weights of poly(methy1 methacrylate) samples were determined by measuring the intrinsic viscosity in benzene at 30" C. The values obtained are quoted in Table 11. There is a progressive decrease of the average molecular weight with an increase in polymerization temperature, but the average molecular weights of polymers prepared in benzene are sensibly higher than those obtained in acetone as a consequence of the precipitant character of the polymerization in benzene. I t is worth noting that the relatively low molecular weight of the polymer prepared in acetone at 80°C supports the suggested complex mechanism of polymerization of this monomer in solution. The stereochemistry of poly(methy1 methacry1ate)s prepared from the corresponding poly( o-methacryloyloxybenzoic acid)s has been studied from the proton- NMR spectra shown in Figure 4. The isotactic, heterotactic, and syndiotactic triad fractions have been calculated by the comparison of integral intensities of the corresponding -CH, resonance signals a t 1.12,0.98, and 0.80 ppm from TMS, r ~ p e c t i v e l y . ~ ~ The results obtained together with those of a poly(methy1 methacrylate), PMMA, prepared by free radical polymerization in the same experimental conditions are quoted in Table 111. It becomes clear that poly( o-methacryloyloxybenzoic acid)s prepared in benzene present isotactic triad fractions higher than those prepared in acetone a t the same temperature, but in all cases the isotacticity is enhanced with respect to PMMA; the heterotactic triad fractions are rather similar in all cases and, logically, there is a decrease of the syndiotactic triad fraction with respect to PMMA. However, the temperature interval used in the present work is not wide enough to observe any effect of the polymerization temperature on the stereostructure of polymers. Similar results have been obtained in the homo- polymerization of other aromatic acrylic and methacrylic esters as well as in their copolymerization with methyl metha~rylate.,~ In this sense, Blumstein et al.I7 have indicated that poly( p-methacryloyloxybenzoic acid)s prepared in different media (i.e., bulk, nematic, and isotropic) present a molar fraction of isotactic, heterotactic, and syndiotactic triads in the range 9-lo%, 35-40%, and 40-50%, respectively, an isotacticity somewhat higher than PMMA.


n 7’””’

Fig. 4. Proton NMR spectra of poly(methy1 methacry1ate)s prepared from the original poly( o-methacryloyloxybenzoic acid)s.

As has been widely r e p ~ r t e d ~ ~ - ~ ’ in free radical polymerization, the stereochemical configuration along the polymer chain is determined during the propagation step through two possible addition reactions: isotactic and syndiotactic propagations. In order to test a particular polymerization mechanism from a stereochemical point of view, it is convenient to express the stereochemical configuration of polymer chains in terms of conditional probabilities. In this way, the isotactic or meso (m) and syndiotactic or racemic (r) dyads, as well as the conditional probabilities of addition of monomer to propagating radicals, p(i,/j), (i, j = m,r), are given in Table IV. p(i/j) represents the probability that the monomer adds in j fashion to an i chain end. The results obtained indicate that the meso and racemic additions to growing chains with racemic radical ends, p(r/r) and p(r/m), are favored over those with meso radical ends, p(m/m) and p(m/r). However, for a determined meso or racemic radical end, there is not any appreciable selectivity of addition, except for the polymer prepared at the lowest temperature. These result indicate that there is not preference for a particular propagation reaction from a

TABLE I11 Stereochemical Configuration of Poly(methy1 methacry1ate)s Prepared from the Original

Poly( o-methacryloyloxybenzoic acid)s

Pol. Temperature Sample (“C) mm m + m rr

P(A - 30) P(A - 60) P(A - 80) PMMA P(B - 60) P(B - 80)

30 60 80 60 60 80

0.16 0.37 0.47 0.12 0.43 0.45 0.12 0.45 0.43 0.06 0.38 0.56 0.18 0.45 0.36 0.21 0.43 0.36


TABLE IV Statistic Configurational Parameters of Poiy(methy1 methacry1ate)s Prepared from the Original

Poly( o-methacryloyloxybenzoic acid)s

P P(A - 30)

0.65 0.34 0.72 0.53 0.47 0.28 1.20 1.10

P(A - 60)

0.66 0.33 0.68 0.64 0.36 0.32 1.03 1.02

P(A - 80) PMMA P(B - 60) P(B - 80)

0.65 0.34 0.66 0.65 0.35 0.34 1 .oo 1.01

0.75 0.25 0.75 0.76 0.24 0.25 0.99 1 .oo

0.58 0.40 0.62 0.55 0.45 0.38 1.05 1.06

0.57 0.42 0.63 0.50 0.50 0.37 1.10 1.10

stereochemical point of view and that the secondary cyclation reaction does not influence appreciably the stereochemistry. Therefore, it seems justified to assume that the secondary cyclation reaction is independent of the free radical propagation, although it is necessary to take into consideration that the formation in the reaction medium of a compound (salicylic acid) that can easily act as a transfer agent modifies the kinetic chain length.

On the other hand, the lack of selectivity for meso or racemic additions of monomer molecules to polymeric growing ends indicates that, from a stereochemical point of view, the propagation step follows the classic Bernoullian statistics. Moreover, the persistence ratios for isotactic (p,) and syndiotactic (qs) sequences listed in Table IV present values very close to unity, which supports this behavior. Only the polymer prepared a t 30°C gives values of p, and q, with a little deviation from unity, which could be explained by the possible formation of aggregates through the carboxylic group at this temperature. However, further investigations would be necessary to clarify this point.

The Bernoullian character of the propagation step has also been tested by applaying the treatment proposed by Bovey et al.34 in which the probability of formation of iso, hetero, and syndiotactic sequences can be expressed as a function of a single isotacticity parameter, u. Figure 5 shows that the experimental points fit adequately the distribution curves calculated from u values. The polymers prepared in acetone present a u value of 0.35, whereas for those obtained in benzene, u = 0.45. In both cases, the values are rather higher than that of PMMA (0.25),34 according to the somewhat greater tendency of o-methacryloyloxybenzoic acid to form isotactic sequences, with respect to methyl methacrylate.

Taking into account the statistical relations proposed by Miller 40 and Johnsen41 and considering the Bernoullian character of the polymerization, Figure 6 shows the weight average distribution functions of isotactic Wi(m) and syndiotactic Ws(m) sequences, together with those of PMMA. The distribution curve of isotactic sequences for polymers prepared in benzene is broader than that of polymers prepared in acetone as a consequence of the longer isotactic sequences of the corresponding polymers. However, the maxima of both curves are closed to a value of m = 2, which indicates that the formation of isotactic dyads is rather more probable in comparison with

POLYMERS FROM o-METHACRYLOYLOXYBENZOIC ACID 213

0.8

0.6

r Oh

Fig. 5. Statistical probabilities of tactic sequences as a function of the isotacticity parameter a.

PMMA, in which the isotactic units are predominantly isolated in syndiotactic sequences. Also, it is worth noting the clear differences between the shape of distribution functions for syndiotactic sequences, which are much broader than the corresponding isotactic ones and present a net maxima that is shifted to lower (m) values for polymers prepared in benzene. Logically, the probability of formation of long syndiotactic sequences is lower for o- methacryloyloxybenzoic acid than for methyl methacrylate.

The authors would like to thank the Comision Asesora de Investigacion Cientifica y Tknica for its support of this work.

0.20

0. IS

W Iml

o .m

am

( rn)

Fig. 6. Weight average sequence distribution functions, W(m) as a function of the monomer units in the sequences (m).


References 1. D. Bailey, D. Tirrell, and 0. Vogl, J. Macromol. Sci., Chem. A , 12(5), 661 (1978). 2. 0. Vogl, Pure Appl. Chem., 51, 2409 (1979). 3. C. G. Overberger and J. Salamone, Accts. Chem. Res., 2, 217 (1969). 4. C. V. Pittman, Jr., Polym. News, 4, 152 (1978). 5. D. Tirrell, D. Bailey, and 0. Vogl, Polym. Prepr. ACS Diu. Polym. Chem., la(l), 542

6. D. Bailey, D. Tirrell, and 0. Vogl, J. Polym. Sci. Polym. Chem. Ed., 14, 2725 (1976). 7. D. Bailey and 0. Vogl, J. Macromol. Sci., Rev. C , 14, 267 (1976). 8. W. Dickstein and 0. Vogl, J. Macromol. Sci., Chem. A , 22(4), 387 (1985). 9. L. G. Donamura and 0. Vogl, Polymeric Drugs, Academic Press, New York, 1978.

(1977).

10. L. G. Donamura, in Progress in Polymer Science, Vol. 4, A.D. Jenkings, Ed., Pergamon

11. H. G. Batz, Ado. Polym. Sci., 23, 25 (1977). 12. J. Fertig, A. I. Goldberg, and M. Skoultini, J. Appl Polym. Sci., 9, 903 (1965). 13. H. S. Patel and D. Daniel, J. Macromol. Sci. Chem. A , 20(4), 453 (1983). 14. G. Ciampa, A. Vittoria, and F. Munna, Ann. Chim., 59, 857 (1969). 15. A. Blumstein, N. Kitagawa, R. Blumstein, Mol. Crystals Liq. Crystals, 12, 215 (1971). 16. A. Blumstein, S. B. Clough, L. Patel, R. B. Blumstein, and E. C. Hsu, Macromolecules, 9,

17. A. Blumstein, R. B. Blumstein, S. B. Clough, and E. C. Hsu, Macromolecules, 8,73 (1975). 18. Yu B. Anerik, I. I. Konstantinov, and B. A. Krentsel, J. Polym. Sci. C, 23, 231 (1968). 19. J. Webr, J. SvobodovB, and F. Hrabhk, CoUect. Czech. Chem. Commun., 41, 738 (1976). 20. F. Hrabhk, M. BezdBk, V. HynkovL, and J. Svobodovi, Mukromol. Chem., 183,2675 (1982). 21. M. BezdBk, V. Hynkova, and F. Hrabhk, Makromol. %hem., 184, 1967 (1983). 22. J. M. Vivas, V. Garcia, L. Bravo, and J. San Romh, to be published. 23. A. Katchalsky and H. Eisemberg, J. Polym. Sci., 6, 145, (1951). 24. T. G. Fox, J. B. Kinsinger, H. F. Mason, and E. M. Schuele, Polymer, 3, 71 (1962). 25. A. M. North, The Kinetics of Free Radical Polymerization, Pergamon Press, Oxford (1966). 26. C. H. Bamford and A. D. Jenkins, Proc. Roy. SOC. A , 228, 220 (1955). 27. G. B. Butler and A. Matsumoto, J. Polym. Sci. Polym. Lett. Ed., 19, 167 (1981). 28. A. Matsumoto, T. Kitamura, M. Oiwa, and G. B. Butler, J. Polym. Sci. Polym. Chem.

29. J. F. Jones, J. Polym. Sci., 33, 15 (1958). 30. J. Mercier and G. Smets, J. Polym. Sci. A , 1, 1491 (1963) 31. I. Imai, A. Matsumoto, and M. Oiwa, J. Polym. Sci. Polym. Chem. Ed., 16, 1421 (1978). 32. A. Eisenberg, T. Yokoyama, and E. Sandalido, J. Polym. Sci. A-1, 7 , 1717 (1969). 33. J. San R o m b , E. L. Madruga, and L. Pargada, t o be published. 34. F. A. Bovey and G. V. Tiers, J. Polym. Sci., 44, 173 (1960). 35. J. San Romiin, E. L. Madruga, and M. A. del Puerto, J. Polym. Sci. Polym. Chem. Ed., 21,

36. R. L. Miller, J. Polym. Sci., 56, 375 (1962). 37. B. D. Coleman and T. G. Fox, J. Polym. Sci. A , 1, 3183 (1963). 38. T. Tsuruta, T. Makimoto, and H. Kanai, J. Macromol. Sci., 1, 31 (1966). 39. F. A. Bovey, High Resolution NMR of Macromolecules, Academic Press, New York (1972). 40. R. L. Miller and L. E. Nielsen, J. Polym. Sci., 46, 303 (1960). 41. V. U. Johnsen, Kobid-z , 178, 161 (1961).

Press, New York, 1974.

243 (1976).

Ed., 19, 2531 (1981).

3303 (1983).

Received September 25, 1985 Accepted March 21,1986

synthesis and microstructure of polymers from o-methacryloyloxybenzoic acid

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