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Structure formation in the stages preceding formation of a crosslinked polymer network
STRUCTURE FORMATION IN THE STAGES PRECEDING FORMATION OF A CROSSLINKED POLYMER NETWORK* M. I. KARYAKINA, M. M. MOGILEVICIt, ~-N. V. MAIOROVA a n d A. V. UDALOV~_ State Research Institute of the Paint and Varnish Industry Yaroslavl' Technological Institute (Received 22 March 1973)
A study has been made of the supermolecular structures in intermediate polymerization products preceding the formation of crosslinked polymers from oligoesteracrylates. It is shown that the supermolecular structure of crosslinked polyr~ers is formed during the actual polymerization process. The supermolecular organization of the intermediate polymerization products must be regarded as the primary structural form with respect to the morphology of the crosslinked poisoners. OLIGOESTERACRYLATES (OEAs), the kinetics of p o l y m e r i z a t i o n of which h a v o been studied in some detail [1], are promising materials for p r o d u c t i o n of polymeric coatings. The f o r m a t i o n of crosslinked O E A polymers does not o c c u r directly f r o m the oligomer b u t from intermediate p o l y m e r i z a t i o n products, t h e so-called "soluble" polymers t,which are oxidized u n s a t u r a t e d c o m p o u n d s with different degrees of branching [2]. The subject of the present p a p e r is a s t u d y of the supermolecular s t r u c t u r e s in the soluble p o l y m e r and the discovery of the role of these in f o r m a t i o n of t h e t h r e e dimensional network. The supermolecular s t r u c t u r e of such polymers has n o t been studied previously, evidently because of the difficulty of isolation o f t h e i n t e r m e d i a t e p r o d u c t s of p o l y m e r i z a t i o n of OEAs and of the p r o c e d u r a l difficulty involved in s t u d y of the s t r u c t u r e of polymers in solution. T h e materials chosen for the investigation were the d i m e t h a c r y l a t e of bis(ethylene glycol) adipate (MEA) and the t e t r a m e t h a c r y l a t e of bis-(trimethylolpropane) adipate (MTPA). The p r e p a r a t i o n , purification and characteristics o f these materials were the same as in reference [1] and [2]. Isolation of the soluble polymers, the life time of which would be 'eomn~,ensurate with the time taken to conduct an experiment, is possible only when the OEA is polymerized in air. The conditions of polymerization of the films and the eharaeteristies of the OEAs at the time of extraetion of the soluble polymer from the fihn are shown in the Table. For isolation of the soluble polymers the proeess of film formation was stopped at stages corresponding to concentrations of erosslinked product of c=20% and 75°/o (Fig. 1). * Vysokomol. soyed. A17: No. 3, 466-470, 1975. ¢ We use the term "soluble" polymer to denote intermediate polymerization products isolated from OEA films.
537
538
M. I. I ~ Y A X n V A
et al.
The sol fraction was extracted with acetone in the cold for 2-3 days and deposited from solution on glass plates. I t was then separated into three broad fractions by successive extraction with solvent (acetone)-precipitant (petroleum ether) mixtures of increasing POLYMERIZATIOI~I COI~I)ITIONS k_~D C H A R A C T E R I S T I C S OF O E ~ s
AT T H E M O M E N T OF I S O L A T I O N
OF SOLUB:LE P O L Y M E R
(Redox system--0"05~/o of 1,1-bishydroperoxydicyclohexyl peroxide-I-0.04% of cobalt naphthenate) Polymerization conditions OEA
ME&
MTPA
T, °C
]
time, rain
Fraction No.
I film ] thickness,/.,
100
30
70
100
60
70
80
40
35
Q u a n t i t y of fraction in film, ~o
I II III I II III I II III
43.3 18.5 16-5 11.2 3.7 6.8 48.4 8.9 21.6
solvent power. The time of extraction of each fraction was 2 hr at 25 ~=0.2 °. The intermediate polymerization products were separated from the solvent-precipitant mixture b y blowing compressed air through the slightly warmed (30-35 °) solutions of the fractions and they were then dissolved in acetone. The concentration of the solutions of all the fractions was 1%. C,%
Z00
~
I 2
2
O0
20
I
50 80 T/me, rn/n
110
Fie. 1. Kinetic curves of polymerization of iVLE/k (1) and I~ITPA (2).
Determination of the physicochemical characteristics and composition of the fractions showed [2] t h a t fraction I contains mainly unreacted oligomer, products of oxidative degradation and polymerization products of low molecular weight, with Pn ~ 2, fraction I I contalus slightly branched, unsaturated compounds, with /~n----2-7 or 8 a n d fraction I I I highly branched, less unsaturated compounds with Pn >/7-8.
Structure formation
539
The supermoleeular structure of the soluble polymers was studied b y the method of t h e r m a l a t t a c h m e n t [4] to a freshly split mica surface, and of the crosslinked polymers b y formation of single stage c a r b o n - p l a t i n u m replicas of the surface of films and etching these in the plasma of a high frequency oxygen discharge [5], following the routine of reference [6]. Opton E ~ - 9 . S - 2 electron microscope was used for the structural investigation.
FIG. 2. Electron photomicrographs of fraction I (c, e), I I (a, ]), I I I (b, d) and a mixture of fractions I - I I I (g) of the soluble polymers of ~VIEA (a-d) and ~ T P / k (e-g), separated from films containing 20% (a, b and e-g) and 75% of crosslinked polymer (c, d), and from a film from MTPA containing 98% of crosslinked polymer
(z).
Examination of the soluble MEA polymers (Fig. 2) isolated after polymerization for 30 rain showed that fraction I is characterized by formation of poorly defined, isolated globules of mean diameter less than 200 A. It may be supposed that these formations are produced by polymerization products of low molecular weight, because no kind of structural form could be brought out from a solution o f the original oligomer on the surface of mica. Better defined globules appear
540
l~. I. : ~ Y ~ : : ~ A
et al.
in fraction II (Fig. 2a). The ordering process is exhibited yet more clearly in fraction III. Here more complex formations made up of globules of diameter 300-400 • (Fig. 2b) separate on the surface of mica. The increase in the complexity of the supermolecular organization on passing from fraction I to fraction I I I can be attributed to increase in the molecular weight and degree of branching of the intermediate polymerization products, to increase in their polarity as a result of oxidation and to beginning of formation of the OEA gel structure. Oxidation during the course of polymerization results in the appearance of peroxide, hydroperoxide, carbonyl and other groups conraining oxygen in the polymer chain, and these promote increased associative ordering of the structural elements. Examination of the soluble MEA polymers isolated after polymerization for 60 min showed that fraction I has single globules and fairly loose associations of globules with clear boundaries (Fig. 2c). In fraction II associations of globules in an elongated, curved shape are formed. In the structural formations of fraction I I I compact associations of globules are seen, the,size and shape of which are similar to those of the structural formations of fraction I (cf. Figs. 2d and 2c). Furthermore a tendency to formation of films on the mica surface appears. Comparison of the supermolecular structures of the soluble MEA polymers isolated after polymerization for 30 and 60 min shows that the main physiological features of fractions I and II, i.e. globules and associations of globules, are preserved, but as the polymerization time is increased the size of the structural formations increases. On the other hand considerable change in the morphology of the structured formations of fraction I I I occurs. This is because the proportion of macromolecules of higher molecular weight and higher degree of branching, which are consumed primarily by formation of crosslinked polymer, decreases in the soluble part of the film as the polymerization time is increased. Thus MEA can form supermolecular structure in the form of globules and associations of globules in the very earliest stages of polymerization. In order to discover whether structural and morphological changes of this type are characteristic of other OEAs producing soluble polymers with a different degree of branching, we investigated the structure of the intermediate products of polymerization of MTPA, oligomers of which have four double bonds per molecule. The polymerization of MTPA was stopped after 40 min. During this time 20% of crosslinked polymer is formed in the film. The soluble part of the MPTA film was separated into three fractions as in the case of the MEA film. On the surface of mica fraction I formed a structureless mass, evidently of oligomer, with some isolated globules dispersed in it, and also well formed globules of size 150-300 A (Fig. 2e). As the molecular weight and degree of branching of the soluble MTPA polymer molecules increases (fraction II) a tendency to formation of associations of globules is seen (Fig. 2f). Formation of globules of diameter 100-150 A is characteristic of fraction III. They separate out on the surface of mica in the form of close packed formations.
Structure formation
541
It may be assumed that such a substantial difference in the size and nature of the mutually ordered supermolecular structures, depending on the degree of branching of the intermediate products formed in the course of polymerization, will affect the heterogeneity of these systems. In fact investigation of a mixture of the MTPA fractions showed that on a uniform background with a structure identical with that of fraction I*, sections are deposited that are morphologically analogous to the structure of fraction III, and around the perimeter of these sections are arranged associations of globules of different sizes, similar to the structural forms of fraction II. This selective character of the distribution of the individual fractions of the soluble polymers on the surface of mica is probably due to difference in their ability to become adsorbed on a mica surface and to the mutual solubility of the fractions in the presence of acetone. It m a y be concluded from the above results that as tile molecular weight of the intermediate products increases their mutual solubility decreases and this is the reason for the formation in fraction I I I of compact, small polymer coils packed together without mutual interpenetration occurring (Fig. 2g). The reduction in solubility of the low molecular weight soluble polymers as the molecular weight increases, with formation of sharp interfacial boundaries causes the system to become inhomogeneous. Reproduction of the structural inhomogeneity in the set film confirms this (Fig. 2h). Analysis of the experimental results suggests the following process of formation of supermolecular structure in the crosslinked polymers. In the initial stage polymerization occurs in the depth of the liquid oligomer, with formation of primary polymer chains, and in micro-regions consisting of aggregates of these primary chains and oligomer immobilized in them [7]. The globular structures seen in fraction I are obviously these micro-aggregates. The globular form of the micro-aggregates, which is the thermodynamically preferred shape, arises as a result of coiling up of the polymer chains. The globules become converted to microgel particles b y polymerization in the coil. Further polymerization brings about increase in the concentration of micro-aggregates with preservation of the same shape. Gel formation occurs as a result of interaction between the microgel particles, i.e. when the soluble polymer passes to crosslinked polymer the globular structure of the intermediate polymerization products becomes fixed. Thus the supermolecular structure of the crosslinked polymers is formed during the course of the polymerization process. The supermolecular organization of the soluble polymers must be regarded as the primary structural form in relation of the morphology of the crosslinked polymers. Chemical interaction between the microgel particles results in formation of a three dimensional network throughout the entire polymerizing system. Translated by E. O. PHILLIPS
* The assignment of the structure to the fractions was achieved by varying the ratio of the fractions in the mixture.
~542
/~'. V. ~AIOROVA et al.
REFERENCES
1. A. A. BERLIN, T. Ya. K E F E L I and G. V. KOROLEV, Poliefirakrilaty (Polyester-acrylates). Izd. " N a u k a " , 1967 2. M. lYl. MOGILEVICH, N. A. SUKHANOVA and G. V. KOROLEV, Vysokomol. soyed. A I 5 : 1478, 1973 (Translated in Polymer Sci. U.S.S.R. 15: 7, 1689, 1973) 3. S. Kh. FAKIROV, N. F. BAKEYEV and V. A. KARGIN, Sb. Mekhanizm protsessov plenkoobrazovaniya iz polimernykh rastvorov i dispersii (Collected Papers. The Mechanism of F i l m F o r m a t i o n from Polymer Solutions and Dispersions). p. 71, Izd. "lqauka", 1966 4. A. L. VOLYNSKII, N. B. ZMIENKO and N. F. BAKEYEV, Vysokomol. soyed. A13: 44, 1971 (Translated in Polymer Sci. U.S.S.R. 13: 1, 47, 1971) 5. I. 1. PETROVA, A. Ye. CHALYKH, A. AVGANOV and V. M. LUK'YANOVICH, Tezisy V I I I konferentsii po elektronnoi mikroskopii (Sunmlarics of Papers Presented at the 8th Conference on Electron Microscopy). Moscow, 1971 6. A. V. UDALOVA, M. I. KARYAKINA, M. M. MO(~ILEVICIt and N. V. MAIOROVA, Vysokomol. soyed. B15: 293, 1973 (Not translated in Polymer Sci. U.S.S.R.) 7. (L V. KOROLEV and A. A. BERLIN, Vysokomol. soyed. 4: 1654, 1962 (Not translated in Polymer Sci. U.S.S.R.).
THE SUPERMOLECULAR STRUCTURE OF CROSSLISKED OLIGOESTERACRYLATES * N. V. MAIOROVA, M. M. MOOILEVlCH, M. I. KARrAKINA and A. V. UDALOVA State Research I n s t i t u t e of the P a i n t and Varnish I n d u s t r y Yaroslavl' Technological I n s t i t u t e
(Received 22 March 1973) A s t u d y has been made of the dependence of the supermolecular organization of crosslinked polymers on the chemical structure of the original oligomers. The interrelationship between chemical structure, kinetic and morphological factors in three dimensional polymerization of oligoesteracrylates is established.
I~ THE present paper the dependence of the supermolecular organization of erosslinked polymers on the chemical structure of the original oligomers is examined, taking oligoesteracrylates (OEA's) and dimethylaerylate esters as examples. Oligoesteracrylates are very convenient model systems for study of structure formation in crosslinked polymers, because the method of synthesis of OEA's makes it possible to control the length and chemical nature of the * Vysokomol. soyed. A17: No. 3, 471476, 1945.
A study has been made of the supermolecular structures in intermediate polymerization products preceding the formation of crosslinked polymers from oligoesteracrylates. It is shown that the supermolecular structure of crosslinked polyr~ers is formed during the actual polymerization process. The supermolecular organization of the intermediate polymerization products must be regarded as the primary structural form with respect to the morphology of the crosslinked poisoners. OLIGOESTERACRYLATES (OEAs), the kinetics of p o l y m e r i z a t i o n of which h a v o been studied in some detail [1], are promising materials for p r o d u c t i o n of polymeric coatings. The f o r m a t i o n of crosslinked O E A polymers does not o c c u r directly f r o m the oligomer b u t from intermediate p o l y m e r i z a t i o n products, t h e so-called "soluble" polymers t,which are oxidized u n s a t u r a t e d c o m p o u n d s with different degrees of branching [2]. The subject of the present p a p e r is a s t u d y of the supermolecular s t r u c t u r e s in the soluble p o l y m e r and the discovery of the role of these in f o r m a t i o n of t h e t h r e e dimensional network. The supermolecular s t r u c t u r e of such polymers has n o t been studied previously, evidently because of the difficulty of isolation o f t h e i n t e r m e d i a t e p r o d u c t s of p o l y m e r i z a t i o n of OEAs and of the p r o c e d u r a l difficulty involved in s t u d y of the s t r u c t u r e of polymers in solution. T h e materials chosen for the investigation were the d i m e t h a c r y l a t e of bis(ethylene glycol) adipate (MEA) and the t e t r a m e t h a c r y l a t e of bis-(trimethylolpropane) adipate (MTPA). The p r e p a r a t i o n , purification and characteristics o f these materials were the same as in reference [1] and [2]. Isolation of the soluble polymers, the life time of which would be 'eomn~,ensurate with the time taken to conduct an experiment, is possible only when the OEA is polymerized in air. The conditions of polymerization of the films and the eharaeteristies of the OEAs at the time of extraetion of the soluble polymer from the fihn are shown in the Table. For isolation of the soluble polymers the proeess of film formation was stopped at stages corresponding to concentrations of erosslinked product of c=20% and 75°/o (Fig. 1). * Vysokomol. soyed. A17: No. 3, 466-470, 1975. ¢ We use the term "soluble" polymer to denote intermediate polymerization products isolated from OEA films.
537
538
M. I. I ~ Y A X n V A
et al.
The sol fraction was extracted with acetone in the cold for 2-3 days and deposited from solution on glass plates. I t was then separated into three broad fractions by successive extraction with solvent (acetone)-precipitant (petroleum ether) mixtures of increasing POLYMERIZATIOI~I COI~I)ITIONS k_~D C H A R A C T E R I S T I C S OF O E ~ s
AT T H E M O M E N T OF I S O L A T I O N
OF SOLUB:LE P O L Y M E R
(Redox system--0"05~/o of 1,1-bishydroperoxydicyclohexyl peroxide-I-0.04% of cobalt naphthenate) Polymerization conditions OEA
ME&
MTPA
T, °C
]
time, rain
Fraction No.
I film ] thickness,/.,
100
30
70
100
60
70
80
40
35
Q u a n t i t y of fraction in film, ~o
I II III I II III I II III
43.3 18.5 16-5 11.2 3.7 6.8 48.4 8.9 21.6
solvent power. The time of extraction of each fraction was 2 hr at 25 ~=0.2 °. The intermediate polymerization products were separated from the solvent-precipitant mixture b y blowing compressed air through the slightly warmed (30-35 °) solutions of the fractions and they were then dissolved in acetone. The concentration of the solutions of all the fractions was 1%. C,%
Z00
~
I 2
2
O0
20
I
50 80 T/me, rn/n
110
Fie. 1. Kinetic curves of polymerization of iVLE/k (1) and I~ITPA (2).
Determination of the physicochemical characteristics and composition of the fractions showed [2] t h a t fraction I contains mainly unreacted oligomer, products of oxidative degradation and polymerization products of low molecular weight, with Pn ~ 2, fraction I I contalus slightly branched, unsaturated compounds, with /~n----2-7 or 8 a n d fraction I I I highly branched, less unsaturated compounds with Pn >/7-8.
Structure formation
539
The supermoleeular structure of the soluble polymers was studied b y the method of t h e r m a l a t t a c h m e n t [4] to a freshly split mica surface, and of the crosslinked polymers b y formation of single stage c a r b o n - p l a t i n u m replicas of the surface of films and etching these in the plasma of a high frequency oxygen discharge [5], following the routine of reference [6]. Opton E ~ - 9 . S - 2 electron microscope was used for the structural investigation.
FIG. 2. Electron photomicrographs of fraction I (c, e), I I (a, ]), I I I (b, d) and a mixture of fractions I - I I I (g) of the soluble polymers of ~VIEA (a-d) and ~ T P / k (e-g), separated from films containing 20% (a, b and e-g) and 75% of crosslinked polymer (c, d), and from a film from MTPA containing 98% of crosslinked polymer
(z).
Examination of the soluble MEA polymers (Fig. 2) isolated after polymerization for 30 rain showed that fraction I is characterized by formation of poorly defined, isolated globules of mean diameter less than 200 A. It may be supposed that these formations are produced by polymerization products of low molecular weight, because no kind of structural form could be brought out from a solution o f the original oligomer on the surface of mica. Better defined globules appear
540
l~. I. : ~ Y ~ : : ~ A
et al.
in fraction II (Fig. 2a). The ordering process is exhibited yet more clearly in fraction III. Here more complex formations made up of globules of diameter 300-400 • (Fig. 2b) separate on the surface of mica. The increase in the complexity of the supermolecular organization on passing from fraction I to fraction I I I can be attributed to increase in the molecular weight and degree of branching of the intermediate polymerization products, to increase in their polarity as a result of oxidation and to beginning of formation of the OEA gel structure. Oxidation during the course of polymerization results in the appearance of peroxide, hydroperoxide, carbonyl and other groups conraining oxygen in the polymer chain, and these promote increased associative ordering of the structural elements. Examination of the soluble MEA polymers isolated after polymerization for 60 min showed that fraction I has single globules and fairly loose associations of globules with clear boundaries (Fig. 2c). In fraction II associations of globules in an elongated, curved shape are formed. In the structural formations of fraction I I I compact associations of globules are seen, the,size and shape of which are similar to those of the structural formations of fraction I (cf. Figs. 2d and 2c). Furthermore a tendency to formation of films on the mica surface appears. Comparison of the supermolecular structures of the soluble MEA polymers isolated after polymerization for 30 and 60 min shows that the main physiological features of fractions I and II, i.e. globules and associations of globules, are preserved, but as the polymerization time is increased the size of the structural formations increases. On the other hand considerable change in the morphology of the structured formations of fraction I I I occurs. This is because the proportion of macromolecules of higher molecular weight and higher degree of branching, which are consumed primarily by formation of crosslinked polymer, decreases in the soluble part of the film as the polymerization time is increased. Thus MEA can form supermolecular structure in the form of globules and associations of globules in the very earliest stages of polymerization. In order to discover whether structural and morphological changes of this type are characteristic of other OEAs producing soluble polymers with a different degree of branching, we investigated the structure of the intermediate products of polymerization of MTPA, oligomers of which have four double bonds per molecule. The polymerization of MTPA was stopped after 40 min. During this time 20% of crosslinked polymer is formed in the film. The soluble part of the MPTA film was separated into three fractions as in the case of the MEA film. On the surface of mica fraction I formed a structureless mass, evidently of oligomer, with some isolated globules dispersed in it, and also well formed globules of size 150-300 A (Fig. 2e). As the molecular weight and degree of branching of the soluble MTPA polymer molecules increases (fraction II) a tendency to formation of associations of globules is seen (Fig. 2f). Formation of globules of diameter 100-150 A is characteristic of fraction III. They separate out on the surface of mica in the form of close packed formations.
Structure formation
541
It may be assumed that such a substantial difference in the size and nature of the mutually ordered supermolecular structures, depending on the degree of branching of the intermediate products formed in the course of polymerization, will affect the heterogeneity of these systems. In fact investigation of a mixture of the MTPA fractions showed that on a uniform background with a structure identical with that of fraction I*, sections are deposited that are morphologically analogous to the structure of fraction III, and around the perimeter of these sections are arranged associations of globules of different sizes, similar to the structural forms of fraction II. This selective character of the distribution of the individual fractions of the soluble polymers on the surface of mica is probably due to difference in their ability to become adsorbed on a mica surface and to the mutual solubility of the fractions in the presence of acetone. It m a y be concluded from the above results that as tile molecular weight of the intermediate products increases their mutual solubility decreases and this is the reason for the formation in fraction I I I of compact, small polymer coils packed together without mutual interpenetration occurring (Fig. 2g). The reduction in solubility of the low molecular weight soluble polymers as the molecular weight increases, with formation of sharp interfacial boundaries causes the system to become inhomogeneous. Reproduction of the structural inhomogeneity in the set film confirms this (Fig. 2h). Analysis of the experimental results suggests the following process of formation of supermolecular structure in the crosslinked polymers. In the initial stage polymerization occurs in the depth of the liquid oligomer, with formation of primary polymer chains, and in micro-regions consisting of aggregates of these primary chains and oligomer immobilized in them [7]. The globular structures seen in fraction I are obviously these micro-aggregates. The globular form of the micro-aggregates, which is the thermodynamically preferred shape, arises as a result of coiling up of the polymer chains. The globules become converted to microgel particles b y polymerization in the coil. Further polymerization brings about increase in the concentration of micro-aggregates with preservation of the same shape. Gel formation occurs as a result of interaction between the microgel particles, i.e. when the soluble polymer passes to crosslinked polymer the globular structure of the intermediate polymerization products becomes fixed. Thus the supermolecular structure of the crosslinked polymers is formed during the course of the polymerization process. The supermolecular organization of the soluble polymers must be regarded as the primary structural form in relation of the morphology of the crosslinked polymers. Chemical interaction between the microgel particles results in formation of a three dimensional network throughout the entire polymerizing system. Translated by E. O. PHILLIPS
* The assignment of the structure to the fractions was achieved by varying the ratio of the fractions in the mixture.
~542
/~'. V. ~AIOROVA et al.
REFERENCES
1. A. A. BERLIN, T. Ya. K E F E L I and G. V. KOROLEV, Poliefirakrilaty (Polyester-acrylates). Izd. " N a u k a " , 1967 2. M. lYl. MOGILEVICH, N. A. SUKHANOVA and G. V. KOROLEV, Vysokomol. soyed. A I 5 : 1478, 1973 (Translated in Polymer Sci. U.S.S.R. 15: 7, 1689, 1973) 3. S. Kh. FAKIROV, N. F. BAKEYEV and V. A. KARGIN, Sb. Mekhanizm protsessov plenkoobrazovaniya iz polimernykh rastvorov i dispersii (Collected Papers. The Mechanism of F i l m F o r m a t i o n from Polymer Solutions and Dispersions). p. 71, Izd. "lqauka", 1966 4. A. L. VOLYNSKII, N. B. ZMIENKO and N. F. BAKEYEV, Vysokomol. soyed. A13: 44, 1971 (Translated in Polymer Sci. U.S.S.R. 13: 1, 47, 1971) 5. I. 1. PETROVA, A. Ye. CHALYKH, A. AVGANOV and V. M. LUK'YANOVICH, Tezisy V I I I konferentsii po elektronnoi mikroskopii (Sunmlarics of Papers Presented at the 8th Conference on Electron Microscopy). Moscow, 1971 6. A. V. UDALOVA, M. I. KARYAKINA, M. M. MO(~ILEVICIt and N. V. MAIOROVA, Vysokomol. soyed. B15: 293, 1973 (Not translated in Polymer Sci. U.S.S.R.) 7. (L V. KOROLEV and A. A. BERLIN, Vysokomol. soyed. 4: 1654, 1962 (Not translated in Polymer Sci. U.S.S.R.).
THE SUPERMOLECULAR STRUCTURE OF CROSSLISKED OLIGOESTERACRYLATES * N. V. MAIOROVA, M. M. MOOILEVlCH, M. I. KARrAKINA and A. V. UDALOVA State Research I n s t i t u t e of the P a i n t and Varnish I n d u s t r y Yaroslavl' Technological I n s t i t u t e
(Received 22 March 1973) A s t u d y has been made of the dependence of the supermolecular organization of crosslinked polymers on the chemical structure of the original oligomers. The interrelationship between chemical structure, kinetic and morphological factors in three dimensional polymerization of oligoesteracrylates is established.
I~ THE present paper the dependence of the supermolecular organization of erosslinked polymers on the chemical structure of the original oligomers is examined, taking oligoesteracrylates (OEA's) and dimethylaerylate esters as examples. Oligoesteracrylates are very convenient model systems for study of structure formation in crosslinked polymers, because the method of synthesis of OEA's makes it possible to control the length and chemical nature of the * Vysokomol. soyed. A17: No. 3, 471476, 1945.