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Carbon chain polymers and copolymers—XLV. Graft copolymers of a methacrylate-modified ω-hydroxyoenanthic acid polyester and styrene or vinyl acetate
CARBON CHAIN POLYMERS AND COPOLYMERS--XLV. GRAFT COPOLYMERS OF A METHACRYLATE-MODIFIED ~o-HYDROXYOENANTHIC ACID POLYESTER AND STYRENE OR VINYL ACETATE* G. S. KOLESNIKOV and G. T. GURZENIDZE Institute of Hetero-organic Compounds, U.S.S.R. Academy of Sciences (Received 18 September 1961} THE possibility of obtaining graft copolymers by copolymerization of methacrylate-modified polyesters of ~-hydroxypelargonic acid and w-hydroxyoenanthic acid has been demonstrated [1, 2]. We have attempted to extend this method to the preparation of graft eopolymers other than those prepared previously [1, 2]. The systems chosen for investigation were a methacrylate-modiiied ~o-hydroxyoenanthie polyester-styrene system and a methacrylate-modified o~-hydroxyoenanthic polyester-vinyl aeetate system. The method of preparation of the co-hydroxyoenanthic aeid polyester and its methacrylate derivative has been described previously [2]. The original polyester had an intrinsic viscosity of 0.22 dl/g (benzene, 20 °) and its molecular weight was 7400 (by titration of terminal earboxyl groups). According to X-ray analysis it had a high degree of order. Examination of a film of the polyhydroxyoenanthate in polarized light between crossed Nicols showed that the film contained spherulites. The hydroxyoenanthie polyester methaerylate (HOEPM) had the same intrinsic viscosity as the original polyester (0.22 dl/g, benzene, 20°). Determination of the moleeualr weight by titration of terminal carboxyl groups and by determination of unsaturation gave a somewhat lower value than that for the original polyester, namely 6000. We have discussed the possible eauses of the reduction in moleeular weight on treatment of a polyester with methacrylyl chloride [2]. HOEPM was eopolymerized with styrene in the presence of 1.7 % of benzoyl peroxide (calculated on the weight of styrene) at 70 ° for 15 hours, in selead, evacuated ampoules. The ratio of styrene: ttOEPM was 83.86:16.14 by weight) or 300:1 (molar, calculated for a molecular weight of HOEPM of 6000.) The eopolymerization product was dissolved in benzene, precipitated by methanol and dried to constant weight in a vacuum desiccator. The yield of precipitated products was 86 % of the weight of the starting materials, and the carbon and hydrogen content (mean of two determinations) was 88-10 and 7.67 % respectively. *Vysokomol. soyed. 5: No. 4, 524-530, 1963. 1195
1196
G.S. KOLESNIKOVand G. T. GURZENIDZE
The product was fractionated to give copolymers of different degrees of grafting. The fractions were precipitated by methanol at 20 ° from a 1% solution of the copolymer in benzene. These fractions, with the exception of the seventh (see Table 1) were washed with acetone. The seventh fraction was almost completely soluble in acetone. The fractions were analysed for carbon and hydrogen and the composition of the graft copolymers was calculated from the carbon content. The thermomechanical properties, the intrinsic viscosity (benzene, 20 °) and the Huggins constant of the graft copolymers were also determined. The results are shown in Table 1 and Figure 1. TABLE 1. FRACTIONATION OF S T Y R E N E - H O E P M COPOLYMERS
Yield of fraction Fraction (% ofweighb ofI No. unfractionated copolymer) 1 2 3 4 5 6 7 Loss
12.2 17.2 16.5 18.5 12.8 12-8 5.1 4.9
Elementary analysis (mean) (%) C 92.20 91.82 91.70 90.03 89.40 87.64 67.02 .
[0] (dl/g)
Huggins con- I n/m stant
Q
H 7.95 7-55 7.88 7.63 7.75 7-85 9.92 .
.
0.535 0.475 0.455 0.440 0.385 0.305 0.230 .
0.18 -0-29 0.0137 0.29 0.0176 0.31 0.0741 0.44 0.0967 0.81 0.1702 1.88 ,15.72 . I --
-3420 2660 630 485 275 3
For all the calculations the molecular weight of the HOEPM was assumed to be 6000. The statistical average frequency of branching was calculated from the formula 1
(n/m) where Q is the distance between the grafted HOEPM branches, expressed as the number of styrene units, n/m the ratio of the number of polyester repeating units (not including the methacrylate group) to the number of styrene units in the graft copolymer, and P the degree of polymerization of the HOEPM. The thermomechanical curves were recorded with the instrument designed by Tsetlin and his collaborators [7], with a load of 100 g and a punch of diameter 4 mm. The i~rst fraction is practically pure polystyrene (calculated analytical figures, C 92"26~/o, H 7-72~/o) and the other fractions are graft copolymers. Presumably the second and third fractions contain very small amounts of polystyrene but we feel t h a t the polystyrene content of these fractions would be so small t h a t it would not affect the properties of the copolymers. None of the thermomechanieal curves show the two points of inflexion typical of mixtures of polymers.
Carbon chain polymers and copolymers--XLV
1197
C,%
i
i 50
100
rempemluve , %
FIQ. 1. Thermomechanical properties of graft copolymer fractions of the product of copolymerization of HOEPM and styrene, of polystyrene and of polyhydroxyoenanthate. 1-- polyhydroxyoenanthate;2-- graft copolymer, Q= 275; 3 - the same, Q=3420; g-polystyrene; 5-graft copolymer, Q=485; 6-products of methanolysis of graft copolymers with Q=485 and 2660; 7--graft copolymer, Q=2660. I t is evident from Table 1 t h a t as the frequency of grafting increases the symmetry of the macromolecules increases, as is shown by an increase in the Huggins constant and simultaneous decrease in intrinsic viscosity. X-ray analysis showed t h a t the degree of order in the graft eopolymers increases with decreasing values of Q, as we found for copolymers of HOEPM and aerylonitrile [2]. TABLE 2. METHANOLYSIS OF GRAFT COPOLYMERS
Original fraction No.
Q
2 3 4 5 6 7
3420 2660 630 485 275 3
Yield of methanolysis product (% of weight of original graft copolymer) Found Calculated 98.0 97-0 90.0 88.0 82.0 4.0
98.3 97.9 91.6 89.4 82.7 4-9
[ t/] (benzene, Huggins 20°) constant (dl/g) 0.57 0.14 0.57 0.14 0.54 0.18 0.53 0.18 0.52 0.21 Not determined
Methanolysis of the graft copolymers, carried out by the method described previously [2], showed (Table 2) t h a t the intrinsic viscosities of the methanolysis products (copolymers of styrene and methyl methacrylate containing very little of the latter) are always higher than those of original graft copolymers, and the Huggins constants are always lower. This indicates t h a t as a result of interaction
1198
G.S. KOLESt~IKOVand G. T. GURZENIDZ~.
between the polyester side chains the graft-copolymer macromoleeules in solution form more symmetrical coils than is the case with polystyrene. A similar effect of polyester side chains was observed by one of us in collaboration with Tszen Khan'-min [3-5]. Although the intrinsic viscosity of the methanolysis products decreases with decreasing Q this fall is slight. This suggests that the length of the main chain of the graft copolymers is almost the same in all cases. The increase in the I-Iuggins constant with decreasing Q can be explained by the presence of methyl methacrylate units in the methanolysis products, which as already stated are copolymers of styrene and methyl methacrylate. The yield of methanolysis products is in good agreement with the yield calculated from the formula A=
Q × 104.14 Q × 104"14~-{-Mgr
• 100
where A is the yield of methanolysis products, %, and M~ is the molecular weight of the grafted side chains split off by methanolysis. In our ease M~ =6000. It is seen from Figure 1 that the graft copolymer with Q =2660 has the highest softening point, at higher and lower values of Q the softening points are lower. We consider that the increase in softening point is a result of interaction between the polyester branches in the condensed phase. When there are few branches there will be no interaction or it will be very weak and the branches will have only a plasticizing effect, thus causing a reduction in softening point. If however the number of branches is above the optimal the thermomechanical properties of the ordered regions of the polyester begin to show their effect on the properties of the graft eopolymers and the softening point of the latter will be determined by the softening point of the polyester. Evidently for thermal ordering of the graft copolymers by interaction of the branches, which are capable of forming ordered structures, it is necessary for the size of the ordered regions to be such that they overlap within certain definite limits. This hypothesis requires further experimental veriiication and it conforms with results obtained previously [3, 4, 6]. The softening point of the methanolysis products differs only slightly from that of polystyrene (see Fig. l, curves 4 and 6) In order to examine the effect of the length of the main chain on the properties of the graft copolymers we copolymerized styrene and HOEPM in the constant ratio of 400:1, with various concentrations of benzoyl peroxide. All other conditions of copolymerization were the same as those described above. The copolymerization products were precipitated from 1 ~/o solution in benzene by the addition of four volumes of methanol. For complete removal of unreacted HOEPM the graft copolymers were washed several times with acetone and dried to constant weight in a vacuum desiccator. The graft eopolymers so obtained were analysed for carbon and hydrogen and the composition was determined from the carbon content. The intrinsic viscosities (benzene, 20°), the I-Iuggins constants and thermomechanieal properties were also determined. For determination of the length of the backbone
Carbon chain polymers and copolymers--XLV
50
~
-100
#50 Ternpemtu~, %
1199
200
Fig. 2. Thermomechanical properties of graft copo]ymers obtained with various
ratios of HOEPM and styrene: /--polystyrene; 2--product of methanolysis of graft eopolymer with [~]=0.28; 3--graft copolymer with [,/]=0.28; 4--product of methanolysis of graft eopolymer with [,/]=0.44; 5--graft eopolymer with [ 7] = 0"44; 6 -- graft eopolymer with [~]= I. 18; 7-- products of methanolysis of graft eopolymers with [~]= 1.18 and 1.92; 8--graft eopolymer with [~]]= 1.92. the graft copolymers were subjected to methanolysis a n d the intrinsic viscosities (benzene, 20°), Huggins constants a n d t h e r m o m e c h a n i c a l properties of the resulting g r a f t copolymers o f styrene a n d m e t h y l m e t h a c r y l a t e were determined. The results are given in Tables 3 a n d 4 a n d in Figure 2. TABLE 3. COPOLYMERIZATIONOF STYRENEAND HOEPM
Expt. No.
1 2 3 4
Benzoyl peroxide concentration (wt. ~o) 0.4 0.8 1.5 3.0
Elementary analysis (mean) (%)
[~] I Huggins (dl/g) constant
nlm
Q
Yield of graft eopolymor
c
H
90.72 90.42 90.65 90.85
7.90 7.77 7.80 7.68
, 1.92 1.18 0-44 0.28
( ~ " %)
0-28 0.42 0.72 1-27
0-0497 0.0604 0.0523 0.0454
940 775 895 1030
83 80 76 70
I t is seen from Table 3 t h a t v a r i a t i o n in initiator c o n c e n t r a t i o n has no effect on the composition of the c o p o l y m e r formed. The p r o p o r t i o n o f s t y r e n e units in the copolymer, calculated from the a n a l y t i c a l results, varies b e t w e e n 94.30 a n d 95.65 moles °/o (from the c a r b o n content). An increase in benzoyl peroxide c o n t e n t leads to a decrease in intrinsic viscosity of the copolymer, as is usual in free-radical polymerization. T h e observed increase in the Huggins c o n s t a n t with decrease in intrinsic viscosity is quite in order, because the s y m m e t r y of a m a c r o m o l e c u l e with a shart b a c k b o n e will be greater t h a n t h a t of a macromolecule with a long
1200
G.S KOLESNIKOVand G. T. (]URZEI~6IDZE .
backbone for the same branch length. The variation in Q is of a random nature and for practical purposes the frequency of branching is the same for all the graft copolymers obtained. TABLE 4. I~ETHANOLYSISOF GRAFTCOPOLYMERS Copolymer from experiment 2fro. 1 2 3 4
Yield of methanolysis product (% of weight of original graft copolymer) Found
Calculated
92 91 92 91
94.2 93.1 94.0 94.7
I I
[ r/] (dl/g)
Huggins constant
2-00 1.40 0.56 0.34
0.25 0.33 0.32 0.87
I t is seen from Table 4 that the intrinsic viscosities of the methanolysis products are higher than those of the original graft copolymers, and the Huggins constants are lower. This indicates that the graft copolymer macromoleeules form more symmetrical coils than the macromolecules of the methanolysis products. Examination of the thermomeehanical properties of the graft copolymers, shown in Figure 2, indicates that the softening point of the eopolymers increases with increasing length of the main chain. This is a result of both the increase in length of the backbone and of the increase in the number of interacting branches, which is consequence of the increased length of the backbone. The fact that the length of the main chain of the graft eopolymer macromolecule influences the thermomeehanical properties of the eopolymer is indicated by the fact that the thermomechanieal properties of the methanolysis products fall off as their intrinsic viscosity decreases. It should be noted that the softening points of the methanolysis products are always below those of the original graft copolymers, consequently the grafting on of polyester side chains brings about (at the given frequency of branching) an increase in the heat resistance of the polymer. We copolymerized H O E P M with vinyl acetate in the presence of 0.2 mole of azobisisobutyronitrile (calculated on the vinyl acetate) for 30 hours at 70 ° in sealed, evacuated ampoules. The resulting copolymers were dissolved in acetone, precipitated from 2 % acetone solution by n-hexane, washed with n-hexane and benzene and dried to constant weight in a vacuum desiccator. The graft copolymers were analysed for carbon and hydrogen, and the composition was determined from the carbon content. The thermomechanical properties and intrinsic viscosities (benzene, 20 °) were also determined and the Huggins constants were calculated. The results are given in Table 5 and Figure 3. Polyvinylacetate obtained under the same conditions had an intrinsic viscosity of 3.63 and the ttuggins constant was 0.22. In all the calculations the molecular weight of the H O E P M was taken as 6000.
Carbon chain polymers and copolymers--XLV
1201
TABLE5. COPOLYMERIZATION0 F HOEPM ANDVINYLACETATE Vinyl acetate: HOEPM molar ratio
Yield of graft copolymer (wt. %)
2000 : 1 400 : 1 200 : 1
88 77 72
Elementary analysis (mean)(%) C H 56-09 57.60 58.35
100 -c,%
~
50
7.19 7.57 7.99
[7] (dl/g)
Huggins constant
3.63 2-40 0.54
0.47 0.39 0.48
_ ~
fO0
150 Tempepolupe, oC
n/m
0.0205 0.151 0.236
Q
2280 310 200
~
200
250
FIG. 3. Thermomechanieal properties of graft copolymers of HOEPM and vinyl acetate: /--graft copolymer, Q=200; 2--the same, Q=310; 3--the same, Q=2280; 4--polyvinylacetate; 5--polyhydroxyoenanthate. I t is seen from Table 5 t h a t with an increase in the proportion of H O E P M in the initial mixture the frequency of grafting increases and the intrinsic viscosity decreases as in the copolymerization of HOEPM and styrene. The Huggius constants of the graft copolymers are higher t h a n t h a t of polyvinylaeetate prepared under the same conditions. Examination of Figure 3 shows t h a t with increasing frequency of grafting the thermomeehanical curves shift toward the lower temperature side. Thus in the copolymers of HOEPM with vinyl acetate the polyester branches exert only a plasticizing effect. X-ray analysis showed t h a t as the value of Q decreases the degree of order in the graft copolymers increases. Examination of films of the graft copolymers of HOEPM with styrene and vinyl acetate in polarized light showed the presence of spherulites in films of fraction No. 6 of the HOEPM-styrene eopolymer (see Table 1), and of the HOEPM-vinyl acetate copolymer of Q=200 (see Table 5). CONCLUSIONS
Copo]ymerization of an co-oenanthic acid polyester methacrylate with styrene and vinyl acetate has yieided graft eopolymers with various degrees of branching. The properties of these in solution and in the condensed state have been studied. Translated by E. O. PHILLIPS
1202
0. YA. FEDOTOVA et al. REFERENCES
1. 2. 3. 4. 5. 6. 7.
6. G. 6. 6. 6. 6. B.
S. S. S. S. S. S. L.
KOLESNJEOV and TSZEN KHAN’- MIN, Vysokomol KOLESNIKOV and 6. T. GUBGENIDZE, Vysokomol. KOLESNIKOV and TSZBN KKAN’- MIN, Vysokomol. KOLESNIKOV and TSZEN KHAN’- MIN, Vysokomol. KOLESNIKOV and TSZEN KHAN’- MIN, Vysokomol. KOLESNIKOV and TSZEN KHAN’- MIN, Vysokomol. TSETLIN et al., Zavod. leb. 22: 352, 1956
soyed. soyed. soyed. soyed. soyed. soyed.
3: 4: 1: 3: 3: 2:
919, 19.61 1709, 1962 1733, 1969 637, 1961 1210, 1961 947, 1960
THE REACTION OF LOWER DICARBOXYLIC ACIDS WITH 4,4’-DIAMINO-3,3’-DIMETHYLDIPHENYLMETHANE
*
0. YA. FEDOTOVA, I. P. LOSEV and S. A. ZAKOSHCHIKOV D. I. Mendeleyev Institute of Chemical Technology, Moscow (Received18 September1961) POLYAMIDATION in the melt as a method of polycondensation of diamines with dicarboxylic acids is not lacking in value. It is sufficient to point out the relative availability of acids in comparison with acid chlorides, and the simplicity of polyamidation in the melt (the absence of solvehts and the need for recovery of these, etc.). The study of this reaction is therefore of practical interest.
Polyamides are usually obtained from aliphatic or aromatic diamines and dibasic acids such as adipic, sebacic, phthalic and terephthalic acids. Little is known of polyamides of the lower dicarboxylic acids, but the production of these is of definite interest because this would provide a use for readily available substances [4,51.
In the work now reported a study was made of the reaction of 4,4’-diamino-3,3’-dimethyldiphenylmethane with some lower dicarboxylic acids-oxalic, malonic, succinic, glutaric and pimelic. During the course of the work, in the choice of the temperature conditions for the reaction, the problem arose of the heat stability of the acids. The decomposition temperatures of the acids were therefore found by a method that we put forward previously for determining the decomposition temperature of polymers [l]. The method seemed to be suitable for the study of the decomposition of dicarboxylic acids. The decomposition temperature we took as the temperature at the point of inflexion in the curve of the change in pressure, because, it is important to know the point where decomposition actually begins (see Fig. 1). Korshak *Vysokomol. soyed. 5: No 4, 531-534, 1963.
1196
G.S. KOLESNIKOVand G. T. GURZENIDZE
The product was fractionated to give copolymers of different degrees of grafting. The fractions were precipitated by methanol at 20 ° from a 1% solution of the copolymer in benzene. These fractions, with the exception of the seventh (see Table 1) were washed with acetone. The seventh fraction was almost completely soluble in acetone. The fractions were analysed for carbon and hydrogen and the composition of the graft copolymers was calculated from the carbon content. The thermomechanical properties, the intrinsic viscosity (benzene, 20 °) and the Huggins constant of the graft copolymers were also determined. The results are shown in Table 1 and Figure 1. TABLE 1. FRACTIONATION OF S T Y R E N E - H O E P M COPOLYMERS
Yield of fraction Fraction (% ofweighb ofI No. unfractionated copolymer) 1 2 3 4 5 6 7 Loss
12.2 17.2 16.5 18.5 12.8 12-8 5.1 4.9
Elementary analysis (mean) (%) C 92.20 91.82 91.70 90.03 89.40 87.64 67.02 .
[0] (dl/g)
Huggins con- I n/m stant
Q
H 7.95 7-55 7.88 7.63 7.75 7-85 9.92 .
.
0.535 0.475 0.455 0.440 0.385 0.305 0.230 .
0.18 -0-29 0.0137 0.29 0.0176 0.31 0.0741 0.44 0.0967 0.81 0.1702 1.88 ,15.72 . I --
-3420 2660 630 485 275 3
For all the calculations the molecular weight of the HOEPM was assumed to be 6000. The statistical average frequency of branching was calculated from the formula 1
(n/m) where Q is the distance between the grafted HOEPM branches, expressed as the number of styrene units, n/m the ratio of the number of polyester repeating units (not including the methacrylate group) to the number of styrene units in the graft copolymer, and P the degree of polymerization of the HOEPM. The thermomechanical curves were recorded with the instrument designed by Tsetlin and his collaborators [7], with a load of 100 g and a punch of diameter 4 mm. The i~rst fraction is practically pure polystyrene (calculated analytical figures, C 92"26~/o, H 7-72~/o) and the other fractions are graft copolymers. Presumably the second and third fractions contain very small amounts of polystyrene but we feel t h a t the polystyrene content of these fractions would be so small t h a t it would not affect the properties of the copolymers. None of the thermomechanieal curves show the two points of inflexion typical of mixtures of polymers.
Carbon chain polymers and copolymers--XLV
1197
C,%
i
i 50
100
rempemluve , %
FIQ. 1. Thermomechanical properties of graft copolymer fractions of the product of copolymerization of HOEPM and styrene, of polystyrene and of polyhydroxyoenanthate. 1-- polyhydroxyoenanthate;2-- graft copolymer, Q= 275; 3 - the same, Q=3420; g-polystyrene; 5-graft copolymer, Q=485; 6-products of methanolysis of graft copolymers with Q=485 and 2660; 7--graft copolymer, Q=2660. I t is evident from Table 1 t h a t as the frequency of grafting increases the symmetry of the macromolecules increases, as is shown by an increase in the Huggins constant and simultaneous decrease in intrinsic viscosity. X-ray analysis showed t h a t the degree of order in the graft eopolymers increases with decreasing values of Q, as we found for copolymers of HOEPM and aerylonitrile [2]. TABLE 2. METHANOLYSIS OF GRAFT COPOLYMERS
Original fraction No.
Q
2 3 4 5 6 7
3420 2660 630 485 275 3
Yield of methanolysis product (% of weight of original graft copolymer) Found Calculated 98.0 97-0 90.0 88.0 82.0 4.0
98.3 97.9 91.6 89.4 82.7 4-9
[ t/] (benzene, Huggins 20°) constant (dl/g) 0.57 0.14 0.57 0.14 0.54 0.18 0.53 0.18 0.52 0.21 Not determined
Methanolysis of the graft copolymers, carried out by the method described previously [2], showed (Table 2) t h a t the intrinsic viscosities of the methanolysis products (copolymers of styrene and methyl methacrylate containing very little of the latter) are always higher than those of original graft copolymers, and the Huggins constants are always lower. This indicates t h a t as a result of interaction
1198
G.S. KOLESt~IKOVand G. T. GURZENIDZ~.
between the polyester side chains the graft-copolymer macromoleeules in solution form more symmetrical coils than is the case with polystyrene. A similar effect of polyester side chains was observed by one of us in collaboration with Tszen Khan'-min [3-5]. Although the intrinsic viscosity of the methanolysis products decreases with decreasing Q this fall is slight. This suggests that the length of the main chain of the graft copolymers is almost the same in all cases. The increase in the I-Iuggins constant with decreasing Q can be explained by the presence of methyl methacrylate units in the methanolysis products, which as already stated are copolymers of styrene and methyl methacrylate. The yield of methanolysis products is in good agreement with the yield calculated from the formula A=
Q × 104.14 Q × 104"14~-{-Mgr
• 100
where A is the yield of methanolysis products, %, and M~ is the molecular weight of the grafted side chains split off by methanolysis. In our ease M~ =6000. It is seen from Figure 1 that the graft copolymer with Q =2660 has the highest softening point, at higher and lower values of Q the softening points are lower. We consider that the increase in softening point is a result of interaction between the polyester branches in the condensed phase. When there are few branches there will be no interaction or it will be very weak and the branches will have only a plasticizing effect, thus causing a reduction in softening point. If however the number of branches is above the optimal the thermomechanical properties of the ordered regions of the polyester begin to show their effect on the properties of the graft eopolymers and the softening point of the latter will be determined by the softening point of the polyester. Evidently for thermal ordering of the graft copolymers by interaction of the branches, which are capable of forming ordered structures, it is necessary for the size of the ordered regions to be such that they overlap within certain definite limits. This hypothesis requires further experimental veriiication and it conforms with results obtained previously [3, 4, 6]. The softening point of the methanolysis products differs only slightly from that of polystyrene (see Fig. l, curves 4 and 6) In order to examine the effect of the length of the main chain on the properties of the graft copolymers we copolymerized styrene and HOEPM in the constant ratio of 400:1, with various concentrations of benzoyl peroxide. All other conditions of copolymerization were the same as those described above. The copolymerization products were precipitated from 1 ~/o solution in benzene by the addition of four volumes of methanol. For complete removal of unreacted HOEPM the graft copolymers were washed several times with acetone and dried to constant weight in a vacuum desiccator. The graft eopolymers so obtained were analysed for carbon and hydrogen and the composition was determined from the carbon content. The intrinsic viscosities (benzene, 20°), the I-Iuggins constants and thermomechanieal properties were also determined. For determination of the length of the backbone
Carbon chain polymers and copolymers--XLV
50
~
-100
#50 Ternpemtu~, %
1199
200
Fig. 2. Thermomechanical properties of graft copo]ymers obtained with various
ratios of HOEPM and styrene: /--polystyrene; 2--product of methanolysis of graft eopolymer with [~]=0.28; 3--graft copolymer with [,/]=0.28; 4--product of methanolysis of graft eopolymer with [,/]=0.44; 5--graft eopolymer with [ 7] = 0"44; 6 -- graft eopolymer with [~]= I. 18; 7-- products of methanolysis of graft eopolymers with [~]= 1.18 and 1.92; 8--graft eopolymer with [~]]= 1.92. the graft copolymers were subjected to methanolysis a n d the intrinsic viscosities (benzene, 20°), Huggins constants a n d t h e r m o m e c h a n i c a l properties of the resulting g r a f t copolymers o f styrene a n d m e t h y l m e t h a c r y l a t e were determined. The results are given in Tables 3 a n d 4 a n d in Figure 2. TABLE 3. COPOLYMERIZATIONOF STYRENEAND HOEPM
Expt. No.
1 2 3 4
Benzoyl peroxide concentration (wt. ~o) 0.4 0.8 1.5 3.0
Elementary analysis (mean) (%)
[~] I Huggins (dl/g) constant
nlm
Q
Yield of graft eopolymor
c
H
90.72 90.42 90.65 90.85
7.90 7.77 7.80 7.68
, 1.92 1.18 0-44 0.28
( ~ " %)
0-28 0.42 0.72 1-27
0-0497 0.0604 0.0523 0.0454
940 775 895 1030
83 80 76 70
I t is seen from Table 3 t h a t v a r i a t i o n in initiator c o n c e n t r a t i o n has no effect on the composition of the c o p o l y m e r formed. The p r o p o r t i o n o f s t y r e n e units in the copolymer, calculated from the a n a l y t i c a l results, varies b e t w e e n 94.30 a n d 95.65 moles °/o (from the c a r b o n content). An increase in benzoyl peroxide c o n t e n t leads to a decrease in intrinsic viscosity of the copolymer, as is usual in free-radical polymerization. T h e observed increase in the Huggins c o n s t a n t with decrease in intrinsic viscosity is quite in order, because the s y m m e t r y of a m a c r o m o l e c u l e with a shart b a c k b o n e will be greater t h a n t h a t of a macromolecule with a long
1200
G.S KOLESNIKOVand G. T. (]URZEI~6IDZE .
backbone for the same branch length. The variation in Q is of a random nature and for practical purposes the frequency of branching is the same for all the graft copolymers obtained. TABLE 4. I~ETHANOLYSISOF GRAFTCOPOLYMERS Copolymer from experiment 2fro. 1 2 3 4
Yield of methanolysis product (% of weight of original graft copolymer) Found
Calculated
92 91 92 91
94.2 93.1 94.0 94.7
I I
[ r/] (dl/g)
Huggins constant
2-00 1.40 0.56 0.34
0.25 0.33 0.32 0.87
I t is seen from Table 4 that the intrinsic viscosities of the methanolysis products are higher than those of the original graft copolymers, and the Huggins constants are lower. This indicates that the graft copolymer macromoleeules form more symmetrical coils than the macromolecules of the methanolysis products. Examination of the thermomeehanical properties of the graft copolymers, shown in Figure 2, indicates that the softening point of the eopolymers increases with increasing length of the main chain. This is a result of both the increase in length of the backbone and of the increase in the number of interacting branches, which is consequence of the increased length of the backbone. The fact that the length of the main chain of the graft eopolymer macromolecule influences the thermomeehanical properties of the eopolymer is indicated by the fact that the thermomechanieal properties of the methanolysis products fall off as their intrinsic viscosity decreases. It should be noted that the softening points of the methanolysis products are always below those of the original graft copolymers, consequently the grafting on of polyester side chains brings about (at the given frequency of branching) an increase in the heat resistance of the polymer. We copolymerized H O E P M with vinyl acetate in the presence of 0.2 mole of azobisisobutyronitrile (calculated on the vinyl acetate) for 30 hours at 70 ° in sealed, evacuated ampoules. The resulting copolymers were dissolved in acetone, precipitated from 2 % acetone solution by n-hexane, washed with n-hexane and benzene and dried to constant weight in a vacuum desiccator. The graft copolymers were analysed for carbon and hydrogen, and the composition was determined from the carbon content. The thermomechanical properties and intrinsic viscosities (benzene, 20 °) were also determined and the Huggins constants were calculated. The results are given in Table 5 and Figure 3. Polyvinylacetate obtained under the same conditions had an intrinsic viscosity of 3.63 and the ttuggins constant was 0.22. In all the calculations the molecular weight of the H O E P M was taken as 6000.
Carbon chain polymers and copolymers--XLV
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TABLE5. COPOLYMERIZATION0 F HOEPM ANDVINYLACETATE Vinyl acetate: HOEPM molar ratio
Yield of graft copolymer (wt. %)
2000 : 1 400 : 1 200 : 1
88 77 72
Elementary analysis (mean)(%) C H 56-09 57.60 58.35
100 -c,%
~
50
7.19 7.57 7.99
[7] (dl/g)
Huggins constant
3.63 2-40 0.54
0.47 0.39 0.48
_ ~
fO0
150 Tempepolupe, oC
n/m
0.0205 0.151 0.236
Q
2280 310 200
~
200
250
FIG. 3. Thermomechanieal properties of graft copolymers of HOEPM and vinyl acetate: /--graft copolymer, Q=200; 2--the same, Q=310; 3--the same, Q=2280; 4--polyvinylacetate; 5--polyhydroxyoenanthate. I t is seen from Table 5 t h a t with an increase in the proportion of H O E P M in the initial mixture the frequency of grafting increases and the intrinsic viscosity decreases as in the copolymerization of HOEPM and styrene. The Huggius constants of the graft copolymers are higher t h a n t h a t of polyvinylaeetate prepared under the same conditions. Examination of Figure 3 shows t h a t with increasing frequency of grafting the thermomeehanical curves shift toward the lower temperature side. Thus in the copolymers of HOEPM with vinyl acetate the polyester branches exert only a plasticizing effect. X-ray analysis showed t h a t as the value of Q decreases the degree of order in the graft copolymers increases. Examination of films of the graft copolymers of HOEPM with styrene and vinyl acetate in polarized light showed the presence of spherulites in films of fraction No. 6 of the HOEPM-styrene eopolymer (see Table 1), and of the HOEPM-vinyl acetate copolymer of Q=200 (see Table 5). CONCLUSIONS
Copo]ymerization of an co-oenanthic acid polyester methacrylate with styrene and vinyl acetate has yieided graft eopolymers with various degrees of branching. The properties of these in solution and in the condensed state have been studied. Translated by E. O. PHILLIPS
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0. YA. FEDOTOVA et al. REFERENCES
1. 2. 3. 4. 5. 6. 7.
6. G. 6. 6. 6. 6. B.
S. S. S. S. S. S. L.
KOLESNJEOV and TSZEN KHAN’- MIN, Vysokomol KOLESNIKOV and 6. T. GUBGENIDZE, Vysokomol. KOLESNIKOV and TSZBN KKAN’- MIN, Vysokomol. KOLESNIKOV and TSZEN KHAN’- MIN, Vysokomol. KOLESNIKOV and TSZEN KHAN’- MIN, Vysokomol. KOLESNIKOV and TSZEN KHAN’- MIN, Vysokomol. TSETLIN et al., Zavod. leb. 22: 352, 1956
soyed. soyed. soyed. soyed. soyed. soyed.
3: 4: 1: 3: 3: 2:
919, 19.61 1709, 1962 1733, 1969 637, 1961 1210, 1961 947, 1960
THE REACTION OF LOWER DICARBOXYLIC ACIDS WITH 4,4’-DIAMINO-3,3’-DIMETHYLDIPHENYLMETHANE
*
0. YA. FEDOTOVA, I. P. LOSEV and S. A. ZAKOSHCHIKOV D. I. Mendeleyev Institute of Chemical Technology, Moscow (Received18 September1961) POLYAMIDATION in the melt as a method of polycondensation of diamines with dicarboxylic acids is not lacking in value. It is sufficient to point out the relative availability of acids in comparison with acid chlorides, and the simplicity of polyamidation in the melt (the absence of solvehts and the need for recovery of these, etc.). The study of this reaction is therefore of practical interest.
Polyamides are usually obtained from aliphatic or aromatic diamines and dibasic acids such as adipic, sebacic, phthalic and terephthalic acids. Little is known of polyamides of the lower dicarboxylic acids, but the production of these is of definite interest because this would provide a use for readily available substances [4,51.
In the work now reported a study was made of the reaction of 4,4’-diamino-3,3’-dimethyldiphenylmethane with some lower dicarboxylic acids-oxalic, malonic, succinic, glutaric and pimelic. During the course of the work, in the choice of the temperature conditions for the reaction, the problem arose of the heat stability of the acids. The decomposition temperatures of the acids were therefore found by a method that we put forward previously for determining the decomposition temperature of polymers [l]. The method seemed to be suitable for the study of the decomposition of dicarboxylic acids. The decomposition temperature we took as the temperature at the point of inflexion in the curve of the change in pressure, because, it is important to know the point where decomposition actually begins (see Fig. 1). Korshak *Vysokomol. soyed. 5: No 4, 531-534, 1963.