- Email: [email protected]
Chloroprene-acrylate copolymer latexes
550
V.I. YELISI~YEVAet al.
I t Could also be that the reason for the anomalous temperature dependence of the molecular weight is the variation in the structure of the catalytic centers. We note that modified catalytic systems are only active in propylene polymerization where there is uncombined aluminium alkyl. The catalytic systems (C2Hs)~O:TiCla%(C2Hs)20:AI(C~H6)a and CsH51~:TiCla~CsHsN:AI(C2Hs) 3 are not active in propylene polymerization. CONCLUSIONS
(1) Modified catalytic systems are more stcreospecific than the original system. (2) The activation energy of propylene polymerization in the presence of mc,dified systems is greater than with the system TiCI3~-AI(C~Hs) 3. (3) There is a very definite "compensation effect" for the catalytic system studied. This amounts to linear dependence between the logarithm of the preexponential factor and the activation energy. (4) The molecular weight of polypropylene prepared in the presence of modified systems is found to rise with temperature in the range 40-70 ° . REFERENCES 1. G. A. RAZUVAYEV, K. F. MINSKER, G. T. FEDOSEYEV and L. A. SAVEL'YEV
Vysokomol. soyed. 1: 1691, 1959 2. 3. 4. 5.
G. J. O. V.
A. RAZUVAYEV and K. S. MINSKER, Vysokomol. soyed. 2: 404, 1960 BOOR, J. Polymer Sei. C1: 237, 1963 N. PIROGOV, Yu. V. KISSIN and N. M. CHIRKOV, Vysokomol. soyed. 5: 633, 1963 I. TSVETKOVA, O. N. PIROGOV, D. M. LISITSIN and N. M. CHIRKOV, Vysokomol.
soyed. 3: 585, 1961 6. G. NATTA, P. PINTO and G. MAZZANTI, Chimica l'industria, 39: 1032, 1957 7. A. P. FIRSOV, N. D. SANDOMIRSKAYA, V. I. TSVETKOVA and N. M. CHIRKOV,
Vysokomol. soyed. 4: 1218, 1962
CHLOROPRENE-ACRYLATE
COPOLYMER
LATEXES*
V. I. YELISEYEVA, N. G. KARAPETYAN, I. S. BOSHNYAKOV and A. S. MARGARYAN Erevan Branch of the Scientific Research Institute of Synthetic Rubber (Received 2 June 1964)
THE possibility of synthesizing latexes based on the emulsion copolymerization of chloroprene with acrylates has been studied. This kind of product may be of considerable practical interest as film-formers and adhesives, and for cer, * Vysokomol. soyed. 7: No. 3, 497-502, 1965.
Cb.loroprene-acrylate copolymer latexes
551
tain other purposes. The chemical combination of acrylates and ehloroprene could extend the temperature range of the elasticity of polyacrylates and increase the resistance of polychloroprene under atmospheric conditions. The presence of chloroprene units in the macromolecules should make it possible for the polymer to be used as a bonding layer in the process of vulcanization. The unsuitable relation of the parameters of chloroprene and acrylate copolymerization [1] has led investigators to doubt the possibility of these monomers being COl~olymerized. We have performed experiments in the emulsion copolymerization of chloroprene with the lower acrylates and methacrylates, and have been able to develop a method of preparing stable colloid latexes on this base. Moreover, it was found that latexes with a wider range of mechanical properties could be prepared by the copolymerization of chloroprene with methyl methacryl~te, for which reason this type of latex was studied in the work. A study of the kinetics of the emulsion copolymerization of ehloroprene (CP) and methylmethacrylate (MMA) showed that a high degree of conversion (93-100~) can be achieved at 60 ° after 4-5 hr. The rate of the process diminishes with rising MMA concentration. The composition of the product copolymers was determined by dissolving them in solvents with selective properties [2]. As solvent we used acetic acid, which dissolves polymethylmethacrylate (PMMA) very well and is without any effect at all on polychloroprene (PCP). Two series of specimens were dissolved, coagulums of copolymeric latexes and latexes of the homopolymers MMA and CP mixed together in ratios corresponding to the composition of the copolymer. The results are given in Table 1. The figures show that the polymers produced by the emulsion copolymerization of CP and MMA in the ratios studied, are practically insoluble in acetic acid. On the other hand, a mix of the corresponding homopolymers iv[ acetic acid will partly dissolve, and the soluble part is equal to the PMMA fraction in the mix. The experiments thus show that all the MMA used in the synthesis enters into eopolymerization with UP. It is also interesting to see whether the copolymerization products contain the homopolymer CP. Since the copolymerization products were insoluble in any of the usual solvents (due to the formation of a cellular structure of course), latexes of the same copolymers were synthesized using diisopropylxanthogenide sulphide as a regulator, since it prevents the formation of a cellular structure. The coagulum of these latexes was fully soluble in the oridinary solvents for PUP, aromatic hydrocarbons, halide-containing haydrocarbons, esters, pyridine. If aniline was added to the PCP solution in pyridine, the polymer separated to form a precipitate. But if aniline was added to the pyridine solution of the product of CP ar.d MMA copolymerization, there was no polymer precipitation. Thus it was found that the UP and MMA copolymer resulting from the eopolymerization contained practically no homopolymer.
552
V . I . ¥ELISE£EVA ~ a/. TABLE 1. SOLUBILITY IN ACETIC ACID OF COPOLYMERS AND MIXES OF HOMOPOLYMER8 OF CHLOROPRENE AND METHYLMETHACRYLATE
Weight ratio CP : MMA in initial emulsion on eopolymerization
in homopolymer mix
Chloroprene content, % (according to analysis) 70.2 60.1 49.9 69.0 60.5 51-0 0
70 • 30 60 : 40 50 : 50 70 60 50 0 100
: 30 : 40 : 50 : 100 :0
100
Methylmethacrylate content, ~o Solubility in (according to ana- acetic acid, % lysis) 29'8 39-9 50.1 31.0 39.5 49.0 100 0
0.8 1.2 1.5 29.7 38.8 47-1 100 0.2
I n order to obtain information on the chain structure of the product copolymers (arrangement of monomer units), we found the copolymerization constant of the monomers, and calculated the probable composition of the copolymet from them. To find the COl~olymerization constant we d~termined the composition of the copolymer at different stages (depth of conversion) of polymerization for monomers in different initial molar ratios (Table 2). The composition of the copolymer was judged from the chlorine content determined b y the Carius method. The full Mayo and Lewis equation [3] was used to calculate the coefficients. The results were as follows: for chloroprenes r 1 = 3.9q-0.25, for methylmethacrylate rs----0.18q-0"06. Using the copolymerization constants we were able to determine not only the composition b u t also the structure of the copolymers. I n the copolymerization of monomers M 1 and M s, the probability of Mx-M 1, Mz-Ms, M2-M1,
i
0'I 0"08
.~ 0"06
M2
~ 0"02 0
"5 10 15 20 NoOfmonomePicunits in/ink
FIG. 1. Distribution of units in macromolecule copolymer chloroprene-methylmethacrylate (molar ratio 8:3) for 50% polymerization of methylmethaerylate. MI-- otdoroprene; M=-- methylmoth~crylate.
Chloroprene-acrylate copolymer h~texes
553
TABLE 2. THEORETICAL RESULTS I~ORTHE COMPOSITIONOF CHLOROPRENE-METHYLMETHACB~YLATE
COPOLY~rER(M~-M~) Monomer content in initial emulsion, reel. %
K1
Total depth of polymerization, mol. °/o
M1
Mi
58.8
41 "2
4.08
initially 10.4 21.2 32.7 43.5 55.9 65.0
69"5
30"5
4.02
79.5
20.5
3.55
initially 15.6 31.4 47.9 61.1 74.0 82.0 initially 12.8 25.8 39.0 52.6 66.3 76.0 84.6
76.3
Composition of copolymer, reel. % M1
MI
85.3 84.6 83.0 80.7 80.1 78.9 75.1 69.2 90.1 89.1 88.5 87.2 85-3 83.8 80.6 93.2 93.0 92.25 91.8 90.7 89.9 88.8 87-4
14-7 15.4 17.0 19.3 19.9 21.1 24.9 30.8 9.9 10.9 11.5 12.8 14.7 16.2 19.4 6-08 7.0 7.75 8.2 9.3 10.1 11-2 12.6
CP conversion, ~o
initially 15 3O 45 60 75 83 90
initially 20 40 60 73 85 95 initially 15 3O 45 60 75 85 93
M2-M ~ b o n d s f o r m i n g in the macromolecules is d i c t a t e d b y t h e relative import a n c e o f t h e a p p r o p r i a t e e l e m e n t a r y r e a c t i o n in the general r a t e of the process of macromoleeule g r o w t h [4]. T h e p r o b a b i l i t y of t h e f o r m a t i o n of these bonds was calculated o n t h e approYimate e q u a t i o n d e v e l o p e d b y Abkin a n d M e d v e d e v ES, 6]. T h e results are shown in Fig. 1. T h e graphs show t h a t m e t h y l m e t h a c r y l a t e units in t h e macromolecules consist m a i n l y o f a single m o n o m e r i c unit, while t h e chloroprene links h a v e several. T h e mechanical properties o f films of t h e latexes p r e p a r e d in t h e m o l a r ratios CP : MMA f r o m 10: 1 t o 7 : 7* were d e t e r m i n e d o n a P o l y a n i a p p a r a t u s w i t h t h e stresses a u t o m a t i c a l l y r e c o r d e d o n t h e film of a n oscillograph [7]. T h e results are s h o w n in T a b l e 3. T h e figures for mechanical properties o f a film o f m e t h y l m e t h a c r y l a t e l a t e x are g i v e n in t h e same place for comparison. *For copolymers with higher MMA content latexes do not form at the ordinary film temperature, due to the rigidity of the polymer.
V . I . YELISEYEVA e t a / .
554
It is evident from Table 3 that latexes forming films of varying degrees of elasticity can be prepared by varying the CP : MMA ratio. These films retain their properties quite well on storage, although some tendency to degradation was found. A comparison of the mechanical properties of the films at different temperatures shows that the temperature range of their elasticity is much greater than for films of acryl polymers. TABLE 3. MECHANICAL PROPERTIES OF FILMS OF CHLOROPRENE-METHYLMETHACRYLATE EMULSION POLYMERS Properties of films Initial molar ratio
elongation on rupture, a t 20 °
10:1 9:2
8:3 7:4 5"7:5 Polymethylacrylate
before ageing
after ageing
1143 1300 1071 681 512"
1143 1100 857 650
980
980
°Io a t 20 ° before ageing
m
501 292 0
modulus of elasticity, kg/cm ~ a t 20 ° before ageing
after ageing
5.86 11"5 24.0 28.8 33.0
5.1 9.3 14.5 21.0 --
6-0
6.0
a t 20 '~ before ageing
98.6 11"09
* Films were dried at 60°, since no film was formed at 20°.
Investigation of the mechanical properties of the copolymer CP with MMA (weight ratio of monomers in the initial emulsion was 7:3) prepared with different degrees of polymerization, showed that the copolymer is gradually enriched with MMA in the process of synthesis. The rigidity of the polymer inereaseswith the depth of polymerization, and the second transition point rises (Table 4). One of the important properties of the latex films is their capacity to absorb water on dampening or wetting. For this reason we studied the kinetics of water absorption by latex films prepared in different monomer ratios. The films were immersed in water. The kinetic curves are shown in Fig. 2. The water absorption curve of an acrylate latex film is shown in the same place for comparison. This demonstrates the advantage of the copolymer latexes. Thus, the maximum water absorption by our films is approx. 10Vo while the acrylate latex films absorb 4 0 ~ water under the same conditions, and its maximum water absorption is 100~. To find the colloidal properties of the copolymer latexes, we determined the size and size-distribution of particles, and also their saturation by an adsorbed layer of emulsifier [8-11]. The l~rtiele size of the latex (molar ratio CT : MMA----8 : 3) was found by electron miseroscopy, and the distribution curve
Chloroprene-acrylate copolymer latexes
555
TABLE 4. PHYSICOMECHANICAL PROPERTIES OF CHLOROPRENE-METHYLMETHACRYLATE COPOLYMER AS DEPENDENT ON THE DEPTH OF MONOMER POLYMERIZATION
(Weight ratio CP : MMA was 7 : 3) Tensile st,rength, g/mm ~
Elongation
Degree of polymerization,
on rupture, O/ /0
%
Modulus with 10% elongation
Modulus with 100% elongation
+20 ° --20 ° +20°I --20 ° -}-20° --20 ° -4-2 0 °
-- 20 °
212 111 84 69
533 556 226 127
98 93 88 84
1517 1993 1910 2260
886 927 1]50 1290
588 578 334 337
908 1073 750 347
136 395 54 288 31 ] ]19 44! 66
Viscous flow point, oC 113 95 97 80
L~
is s h o w n in Fig. 3. I t is e v i d e n t f r o m t h e results t h a t the latexes are quite m o n o dispersed; t h e m e a n d i a m e t e r o f t h e particles is a p p r o x . 770 A. T o find t h e c a p a c i t y of t h e particle surface for s a t u r a t i o n b y t h e emulsifier, a n d a t t h e s a m e t i m e t o d e t e r m i n e t h e i r d i a m e t e r , we u s e d a m e t h o d b a s e d on t h e t i t r a t i o n of t h e l a t e x b y t h e emulsifier until a c o n s t a n t surface tension level was reached, c o r r e s p o n d i n g t o mieelle f o r m a t i o n of critical c o n c e n t r a t i o n [12, 13]. T h e calculations s h o w e d t h a t in t h e process of l a t e x s y n t h e s i s t h e particle surface reaches 65 ~ emulsifier s a t u r a t i o n . As d e t e r m i n e d b y this m e t h o d t h e p a r ticle d i a m e t e r w a s 570 A, which is a p p r o x i m a t e l y t h e s a m e as t h e m e a n diam e t e r of t h e particles d e t e r m i n e d b y electron microscopy.
4~ 40
/ /
y --
/ /
// / /
--
/
1
//
/
2 50
100
150 Time,hr
200
250
300
FIe. 2. Kinetic curves of water absorption by latex films of the eopolymers. Molar ratio CP :MMA (in rnols): 1--10: 1; 2 - - 9 : 2; 3 - - 8 : 3 ; 4--ethyl acrylate: MMA 6.5 : 3.5. T h e figures o b t a i n e d for particle size a n d t h e s a t u r a t i o n of t h e i r surface b y t h e emulsifier show t h a t t h e new c o p o l y m e r latexes h a v e s a t i s f a c t o r y stability.
V. I. YELISEYEVAel~ a[.
556
The properties of the new latexes are such t h a t t h e y can be successfully used as film formers and impregnants. Serious production of these materials has therefore been organized.
°5O
10 4OO 8O0 1200 Diameterof po/gmee poetic/e, J
FIO. 3. Particle size distribution in latex of chloroprene-methylmethaorylate copolymer (molar ratio 8 : 3). CONCLUSIONS (1) Researches have been carried out into the preparation and investigation of the properties of chloroprene-acrylate eopolymer latexes. (2) The copolymers formed as a result of copolymerization of these monomers have different properties from a mechanical mix of the corresponding homopolymers. (3) The Mayo and Lewis constants have been determined experimentally for the emulsion copolymerization of chloroprene and methylmethacrylate. (4) The constants found have been used to calculate the probable structure of the copolymer (8 tools chloroprene-3 tools methy|methacrylate). I t is characterized by alternating arrangement of different amounts of ehioroprene units and one methylmethacrylate unit. (5) At certain chloroprene-methylmethacrylate molar ratios latexes are formed which are of definite interest as film formers. They have colloidal stability and high dispersion, and form films which are exceptionally resistant to water, satisfactorily resistant to ageing, and retain their elasticity in quite a wide temperature range. Tranela~d by V. ALFORD
REFERENCES 1. L. I. YOUNG, J. Polymer Sei. 54: 411, 1961 2. C. S. MARVEL, G. D. JONES, T. W. MARTIN and G. S(.~IETZ, J. Amer. Chem. Soe. 64: 2356, 1942 3. K. MAYO and M. LEWIS, J. ~ner. Cl~em. Soc. 66: 1594, 1944 4. E. T. WALL, J. ~_mer. Chem. Soc. 66: 2050, 1944 5. A. D. ABKIN and S. S. MEDVEDEV, Dokl. Akad. Nauk SSSR, 56: 177, 1947 6. A. D. ABK]N and S. S. MEDVEDEV, Tr. III. Konf. po vysokomol, soyed., Izd. _a~cl. Nauk SSSR, 1948
Synthesis of polycarbonates
557
7. V. I. YELISEYEVA: Polimorn. plenkoobr, d. otdelki kozhi. (Polimeric Film Formers for Dressing Leather.) Ros. tekh. izdat., 1961 8. B. JACORI, Angew. Chem. 64: 539, 1952 9. M. (L ZWICKER, Industrial Engineering Chemistry 44: 774, 1952 10. V. N. TSVETKOV and Ye. M. ALEKSA-NDROVA, Khim. prom. 5: 20, 1958 11. A. V. LEBEDEV, N. A. FERMOV and S. M. MINTS, Sb. Sintez lateksov i ikh primeneniye. (Collection. Synthesis and Use of Latexes.) Gost. k_him, izdat., 128, 1961 12. S. H. MARON, M. K. ELDA and J. N. ULLVITRET, J. Colloid. Sci. 9: 89, 236, 347, 1964 13. S. H. MARON and W. W. BOWLER, J. Amer. Chem. See. 70: 3893, 1948
SYNTHESIS AND STUDY OF POLYCARBONATES FROM 2,2-DI-(4-HYDROXy-3-METHYLPffENYL) PROPANES AND 1,1-DI-(4-HYDROXY-3-METHYLPHENYL) CYCLOIIE.XANES* O. V. SMIRNOVA, E L SAID A L l KHASAN, ( t h e l a t e ) I. P. LOSEV a n d G. S. K O L E S N I K O V I. M. Mendeleyov Moscow Chemieo-Technological Institute (Received 4 June 1964)
THE polycarbonate prepared based on 2,2-di-(4-oxyphenyl)propane (diane) is heat resistant and objects made of it retain their dimensions quite well although its hydrolytic resistance is inadequate [1]. In our opinion interest attaches to the synthesis and study of the properties of polyearbonates based on diphenols, which are similar to dianes but contain other substituents both in the aromatic rings and at the carbon atom which acts as a link between these rings. For this purpose we used polyearbonates for which the starting diphenols were 2,2-di-(4-hydroxy-3-methylphenyl)propane (DOMP) and 1,1-di(4-hydroxy-3-methylphenyl)cyclohexane (DOMC). Mixed polycarbonates on DOMP ar.d DOMC base have been described in the literature [1-4, 7]. But, although highly suitable for the synthesis of polycarbonates, the literature contains no description of the procedure for preparing homopolycarbonates on base of these diphenyls, nor for the optimum conditions for the process of interracial polycondensation. EXPERIMENTAL DOMP was prepared by condensing o-cresol and acetone in the molar ratio o-cresol : acetone=5 : 1 in toluene using dry hydrogen chloride as the catalyst. The DOMP separated was filtered off and recrystallized from dilute acetic acid. In the same way, from o-cresol * Vysokomo]. soyed. 7: No. 3, 503-508, 1965.
V.I. YELISI~YEVAet al.
I t Could also be that the reason for the anomalous temperature dependence of the molecular weight is the variation in the structure of the catalytic centers. We note that modified catalytic systems are only active in propylene polymerization where there is uncombined aluminium alkyl. The catalytic systems (C2Hs)~O:TiCla%(C2Hs)20:AI(C~H6)a and CsH51~:TiCla~CsHsN:AI(C2Hs) 3 are not active in propylene polymerization. CONCLUSIONS
(1) Modified catalytic systems are more stcreospecific than the original system. (2) The activation energy of propylene polymerization in the presence of mc,dified systems is greater than with the system TiCI3~-AI(C~Hs) 3. (3) There is a very definite "compensation effect" for the catalytic system studied. This amounts to linear dependence between the logarithm of the preexponential factor and the activation energy. (4) The molecular weight of polypropylene prepared in the presence of modified systems is found to rise with temperature in the range 40-70 ° . REFERENCES 1. G. A. RAZUVAYEV, K. F. MINSKER, G. T. FEDOSEYEV and L. A. SAVEL'YEV
Vysokomol. soyed. 1: 1691, 1959 2. 3. 4. 5.
G. J. O. V.
A. RAZUVAYEV and K. S. MINSKER, Vysokomol. soyed. 2: 404, 1960 BOOR, J. Polymer Sei. C1: 237, 1963 N. PIROGOV, Yu. V. KISSIN and N. M. CHIRKOV, Vysokomol. soyed. 5: 633, 1963 I. TSVETKOVA, O. N. PIROGOV, D. M. LISITSIN and N. M. CHIRKOV, Vysokomol.
soyed. 3: 585, 1961 6. G. NATTA, P. PINTO and G. MAZZANTI, Chimica l'industria, 39: 1032, 1957 7. A. P. FIRSOV, N. D. SANDOMIRSKAYA, V. I. TSVETKOVA and N. M. CHIRKOV,
Vysokomol. soyed. 4: 1218, 1962
CHLOROPRENE-ACRYLATE
COPOLYMER
LATEXES*
V. I. YELISEYEVA, N. G. KARAPETYAN, I. S. BOSHNYAKOV and A. S. MARGARYAN Erevan Branch of the Scientific Research Institute of Synthetic Rubber (Received 2 June 1964)
THE possibility of synthesizing latexes based on the emulsion copolymerization of chloroprene with acrylates has been studied. This kind of product may be of considerable practical interest as film-formers and adhesives, and for cer, * Vysokomol. soyed. 7: No. 3, 497-502, 1965.
Cb.loroprene-acrylate copolymer latexes
551
tain other purposes. The chemical combination of acrylates and ehloroprene could extend the temperature range of the elasticity of polyacrylates and increase the resistance of polychloroprene under atmospheric conditions. The presence of chloroprene units in the macromolecules should make it possible for the polymer to be used as a bonding layer in the process of vulcanization. The unsuitable relation of the parameters of chloroprene and acrylate copolymerization [1] has led investigators to doubt the possibility of these monomers being COl~olymerized. We have performed experiments in the emulsion copolymerization of chloroprene with the lower acrylates and methacrylates, and have been able to develop a method of preparing stable colloid latexes on this base. Moreover, it was found that latexes with a wider range of mechanical properties could be prepared by the copolymerization of chloroprene with methyl methacryl~te, for which reason this type of latex was studied in the work. A study of the kinetics of the emulsion copolymerization of ehloroprene (CP) and methylmethacrylate (MMA) showed that a high degree of conversion (93-100~) can be achieved at 60 ° after 4-5 hr. The rate of the process diminishes with rising MMA concentration. The composition of the product copolymers was determined by dissolving them in solvents with selective properties [2]. As solvent we used acetic acid, which dissolves polymethylmethacrylate (PMMA) very well and is without any effect at all on polychloroprene (PCP). Two series of specimens were dissolved, coagulums of copolymeric latexes and latexes of the homopolymers MMA and CP mixed together in ratios corresponding to the composition of the copolymer. The results are given in Table 1. The figures show that the polymers produced by the emulsion copolymerization of CP and MMA in the ratios studied, are practically insoluble in acetic acid. On the other hand, a mix of the corresponding homopolymers iv[ acetic acid will partly dissolve, and the soluble part is equal to the PMMA fraction in the mix. The experiments thus show that all the MMA used in the synthesis enters into eopolymerization with UP. It is also interesting to see whether the copolymerization products contain the homopolymer CP. Since the copolymerization products were insoluble in any of the usual solvents (due to the formation of a cellular structure of course), latexes of the same copolymers were synthesized using diisopropylxanthogenide sulphide as a regulator, since it prevents the formation of a cellular structure. The coagulum of these latexes was fully soluble in the oridinary solvents for PUP, aromatic hydrocarbons, halide-containing haydrocarbons, esters, pyridine. If aniline was added to the PCP solution in pyridine, the polymer separated to form a precipitate. But if aniline was added to the pyridine solution of the product of CP ar.d MMA copolymerization, there was no polymer precipitation. Thus it was found that the UP and MMA copolymer resulting from the eopolymerization contained practically no homopolymer.
552
V . I . ¥ELISE£EVA ~ a/. TABLE 1. SOLUBILITY IN ACETIC ACID OF COPOLYMERS AND MIXES OF HOMOPOLYMER8 OF CHLOROPRENE AND METHYLMETHACRYLATE
Weight ratio CP : MMA in initial emulsion on eopolymerization
in homopolymer mix
Chloroprene content, % (according to analysis) 70.2 60.1 49.9 69.0 60.5 51-0 0
70 • 30 60 : 40 50 : 50 70 60 50 0 100
: 30 : 40 : 50 : 100 :0
100
Methylmethacrylate content, ~o Solubility in (according to ana- acetic acid, % lysis) 29'8 39-9 50.1 31.0 39.5 49.0 100 0
0.8 1.2 1.5 29.7 38.8 47-1 100 0.2
I n order to obtain information on the chain structure of the product copolymers (arrangement of monomer units), we found the copolymerization constant of the monomers, and calculated the probable composition of the copolymet from them. To find the COl~olymerization constant we d~termined the composition of the copolymer at different stages (depth of conversion) of polymerization for monomers in different initial molar ratios (Table 2). The composition of the copolymer was judged from the chlorine content determined b y the Carius method. The full Mayo and Lewis equation [3] was used to calculate the coefficients. The results were as follows: for chloroprenes r 1 = 3.9q-0.25, for methylmethacrylate rs----0.18q-0"06. Using the copolymerization constants we were able to determine not only the composition b u t also the structure of the copolymers. I n the copolymerization of monomers M 1 and M s, the probability of Mx-M 1, Mz-Ms, M2-M1,
i
0'I 0"08
.~ 0"06
M2
~ 0"02 0
"5 10 15 20 NoOfmonomePicunits in/ink
FIG. 1. Distribution of units in macromolecule copolymer chloroprene-methylmethacrylate (molar ratio 8:3) for 50% polymerization of methylmethaerylate. MI-- otdoroprene; M=-- methylmoth~crylate.
Chloroprene-acrylate copolymer h~texes
553
TABLE 2. THEORETICAL RESULTS I~ORTHE COMPOSITIONOF CHLOROPRENE-METHYLMETHACB~YLATE
COPOLY~rER(M~-M~) Monomer content in initial emulsion, reel. %
K1
Total depth of polymerization, mol. °/o
M1
Mi
58.8
41 "2
4.08
initially 10.4 21.2 32.7 43.5 55.9 65.0
69"5
30"5
4.02
79.5
20.5
3.55
initially 15.6 31.4 47.9 61.1 74.0 82.0 initially 12.8 25.8 39.0 52.6 66.3 76.0 84.6
76.3
Composition of copolymer, reel. % M1
MI
85.3 84.6 83.0 80.7 80.1 78.9 75.1 69.2 90.1 89.1 88.5 87.2 85-3 83.8 80.6 93.2 93.0 92.25 91.8 90.7 89.9 88.8 87-4
14-7 15.4 17.0 19.3 19.9 21.1 24.9 30.8 9.9 10.9 11.5 12.8 14.7 16.2 19.4 6-08 7.0 7.75 8.2 9.3 10.1 11-2 12.6
CP conversion, ~o
initially 15 3O 45 60 75 83 90
initially 20 40 60 73 85 95 initially 15 3O 45 60 75 85 93
M2-M ~ b o n d s f o r m i n g in the macromolecules is d i c t a t e d b y t h e relative import a n c e o f t h e a p p r o p r i a t e e l e m e n t a r y r e a c t i o n in the general r a t e of the process of macromoleeule g r o w t h [4]. T h e p r o b a b i l i t y of t h e f o r m a t i o n of these bonds was calculated o n t h e approYimate e q u a t i o n d e v e l o p e d b y Abkin a n d M e d v e d e v ES, 6]. T h e results are shown in Fig. 1. T h e graphs show t h a t m e t h y l m e t h a c r y l a t e units in t h e macromolecules consist m a i n l y o f a single m o n o m e r i c unit, while t h e chloroprene links h a v e several. T h e mechanical properties o f films of t h e latexes p r e p a r e d in t h e m o l a r ratios CP : MMA f r o m 10: 1 t o 7 : 7* were d e t e r m i n e d o n a P o l y a n i a p p a r a t u s w i t h t h e stresses a u t o m a t i c a l l y r e c o r d e d o n t h e film of a n oscillograph [7]. T h e results are s h o w n in T a b l e 3. T h e figures for mechanical properties o f a film o f m e t h y l m e t h a c r y l a t e l a t e x are g i v e n in t h e same place for comparison. *For copolymers with higher MMA content latexes do not form at the ordinary film temperature, due to the rigidity of the polymer.
V . I . YELISEYEVA e t a / .
554
It is evident from Table 3 that latexes forming films of varying degrees of elasticity can be prepared by varying the CP : MMA ratio. These films retain their properties quite well on storage, although some tendency to degradation was found. A comparison of the mechanical properties of the films at different temperatures shows that the temperature range of their elasticity is much greater than for films of acryl polymers. TABLE 3. MECHANICAL PROPERTIES OF FILMS OF CHLOROPRENE-METHYLMETHACRYLATE EMULSION POLYMERS Properties of films Initial molar ratio
elongation on rupture, a t 20 °
10:1 9:2
8:3 7:4 5"7:5 Polymethylacrylate
before ageing
after ageing
1143 1300 1071 681 512"
1143 1100 857 650
980
980
°Io a t 20 ° before ageing
m
501 292 0
modulus of elasticity, kg/cm ~ a t 20 ° before ageing
after ageing
5.86 11"5 24.0 28.8 33.0
5.1 9.3 14.5 21.0 --
6-0
6.0
a t 20 '~ before ageing
98.6 11"09
* Films were dried at 60°, since no film was formed at 20°.
Investigation of the mechanical properties of the copolymer CP with MMA (weight ratio of monomers in the initial emulsion was 7:3) prepared with different degrees of polymerization, showed that the copolymer is gradually enriched with MMA in the process of synthesis. The rigidity of the polymer inereaseswith the depth of polymerization, and the second transition point rises (Table 4). One of the important properties of the latex films is their capacity to absorb water on dampening or wetting. For this reason we studied the kinetics of water absorption by latex films prepared in different monomer ratios. The films were immersed in water. The kinetic curves are shown in Fig. 2. The water absorption curve of an acrylate latex film is shown in the same place for comparison. This demonstrates the advantage of the copolymer latexes. Thus, the maximum water absorption by our films is approx. 10Vo while the acrylate latex films absorb 4 0 ~ water under the same conditions, and its maximum water absorption is 100~. To find the colloidal properties of the copolymer latexes, we determined the size and size-distribution of particles, and also their saturation by an adsorbed layer of emulsifier [8-11]. The l~rtiele size of the latex (molar ratio CT : MMA----8 : 3) was found by electron miseroscopy, and the distribution curve
Chloroprene-acrylate copolymer latexes
555
TABLE 4. PHYSICOMECHANICAL PROPERTIES OF CHLOROPRENE-METHYLMETHACRYLATE COPOLYMER AS DEPENDENT ON THE DEPTH OF MONOMER POLYMERIZATION
(Weight ratio CP : MMA was 7 : 3) Tensile st,rength, g/mm ~
Elongation
Degree of polymerization,
on rupture, O/ /0
%
Modulus with 10% elongation
Modulus with 100% elongation
+20 ° --20 ° +20°I --20 ° -}-20° --20 ° -4-2 0 °
-- 20 °
212 111 84 69
533 556 226 127
98 93 88 84
1517 1993 1910 2260
886 927 1]50 1290
588 578 334 337
908 1073 750 347
136 395 54 288 31 ] ]19 44! 66
Viscous flow point, oC 113 95 97 80
L~
is s h o w n in Fig. 3. I t is e v i d e n t f r o m t h e results t h a t the latexes are quite m o n o dispersed; t h e m e a n d i a m e t e r o f t h e particles is a p p r o x . 770 A. T o find t h e c a p a c i t y of t h e particle surface for s a t u r a t i o n b y t h e emulsifier, a n d a t t h e s a m e t i m e t o d e t e r m i n e t h e i r d i a m e t e r , we u s e d a m e t h o d b a s e d on t h e t i t r a t i o n of t h e l a t e x b y t h e emulsifier until a c o n s t a n t surface tension level was reached, c o r r e s p o n d i n g t o mieelle f o r m a t i o n of critical c o n c e n t r a t i o n [12, 13]. T h e calculations s h o w e d t h a t in t h e process of l a t e x s y n t h e s i s t h e particle surface reaches 65 ~ emulsifier s a t u r a t i o n . As d e t e r m i n e d b y this m e t h o d t h e p a r ticle d i a m e t e r w a s 570 A, which is a p p r o x i m a t e l y t h e s a m e as t h e m e a n diam e t e r of t h e particles d e t e r m i n e d b y electron microscopy.
4~ 40
/ /
y --
/ /
// / /
--
/
1
//
/
2 50
100
150 Time,hr
200
250
300
FIe. 2. Kinetic curves of water absorption by latex films of the eopolymers. Molar ratio CP :MMA (in rnols): 1--10: 1; 2 - - 9 : 2; 3 - - 8 : 3 ; 4--ethyl acrylate: MMA 6.5 : 3.5. T h e figures o b t a i n e d for particle size a n d t h e s a t u r a t i o n of t h e i r surface b y t h e emulsifier show t h a t t h e new c o p o l y m e r latexes h a v e s a t i s f a c t o r y stability.
V. I. YELISEYEVAel~ a[.
556
The properties of the new latexes are such t h a t t h e y can be successfully used as film formers and impregnants. Serious production of these materials has therefore been organized.
°5O
10 4OO 8O0 1200 Diameterof po/gmee poetic/e, J
FIO. 3. Particle size distribution in latex of chloroprene-methylmethaorylate copolymer (molar ratio 8 : 3). CONCLUSIONS (1) Researches have been carried out into the preparation and investigation of the properties of chloroprene-acrylate eopolymer latexes. (2) The copolymers formed as a result of copolymerization of these monomers have different properties from a mechanical mix of the corresponding homopolymers. (3) The Mayo and Lewis constants have been determined experimentally for the emulsion copolymerization of chloroprene and methylmethacrylate. (4) The constants found have been used to calculate the probable structure of the copolymer (8 tools chloroprene-3 tools methy|methacrylate). I t is characterized by alternating arrangement of different amounts of ehioroprene units and one methylmethacrylate unit. (5) At certain chloroprene-methylmethacrylate molar ratios latexes are formed which are of definite interest as film formers. They have colloidal stability and high dispersion, and form films which are exceptionally resistant to water, satisfactorily resistant to ageing, and retain their elasticity in quite a wide temperature range. Tranela~d by V. ALFORD
REFERENCES 1. L. I. YOUNG, J. Polymer Sei. 54: 411, 1961 2. C. S. MARVEL, G. D. JONES, T. W. MARTIN and G. S(.~IETZ, J. Amer. Chem. Soe. 64: 2356, 1942 3. K. MAYO and M. LEWIS, J. ~ner. Cl~em. Soc. 66: 1594, 1944 4. E. T. WALL, J. ~_mer. Chem. Soc. 66: 2050, 1944 5. A. D. ABKIN and S. S. MEDVEDEV, Dokl. Akad. Nauk SSSR, 56: 177, 1947 6. A. D. ABK]N and S. S. MEDVEDEV, Tr. III. Konf. po vysokomol, soyed., Izd. _a~cl. Nauk SSSR, 1948
Synthesis of polycarbonates
557
7. V. I. YELISEYEVA: Polimorn. plenkoobr, d. otdelki kozhi. (Polimeric Film Formers for Dressing Leather.) Ros. tekh. izdat., 1961 8. B. JACORI, Angew. Chem. 64: 539, 1952 9. M. (L ZWICKER, Industrial Engineering Chemistry 44: 774, 1952 10. V. N. TSVETKOV and Ye. M. ALEKSA-NDROVA, Khim. prom. 5: 20, 1958 11. A. V. LEBEDEV, N. A. FERMOV and S. M. MINTS, Sb. Sintez lateksov i ikh primeneniye. (Collection. Synthesis and Use of Latexes.) Gost. k_him, izdat., 128, 1961 12. S. H. MARON, M. K. ELDA and J. N. ULLVITRET, J. Colloid. Sci. 9: 89, 236, 347, 1964 13. S. H. MARON and W. W. BOWLER, J. Amer. Chem. See. 70: 3893, 1948
SYNTHESIS AND STUDY OF POLYCARBONATES FROM 2,2-DI-(4-HYDROXy-3-METHYLPffENYL) PROPANES AND 1,1-DI-(4-HYDROXY-3-METHYLPHENYL) CYCLOIIE.XANES* O. V. SMIRNOVA, E L SAID A L l KHASAN, ( t h e l a t e ) I. P. LOSEV a n d G. S. K O L E S N I K O V I. M. Mendeleyov Moscow Chemieo-Technological Institute (Received 4 June 1964)
THE polycarbonate prepared based on 2,2-di-(4-oxyphenyl)propane (diane) is heat resistant and objects made of it retain their dimensions quite well although its hydrolytic resistance is inadequate [1]. In our opinion interest attaches to the synthesis and study of the properties of polyearbonates based on diphenols, which are similar to dianes but contain other substituents both in the aromatic rings and at the carbon atom which acts as a link between these rings. For this purpose we used polyearbonates for which the starting diphenols were 2,2-di-(4-hydroxy-3-methylphenyl)propane (DOMP) and 1,1-di(4-hydroxy-3-methylphenyl)cyclohexane (DOMC). Mixed polycarbonates on DOMP ar.d DOMC base have been described in the literature [1-4, 7]. But, although highly suitable for the synthesis of polycarbonates, the literature contains no description of the procedure for preparing homopolycarbonates on base of these diphenyls, nor for the optimum conditions for the process of interracial polycondensation. EXPERIMENTAL DOMP was prepared by condensing o-cresol and acetone in the molar ratio o-cresol : acetone=5 : 1 in toluene using dry hydrogen chloride as the catalyst. The DOMP separated was filtered off and recrystallized from dilute acetic acid. In the same way, from o-cresol * Vysokomo]. soyed. 7: No. 3, 503-508, 1965.