Topologische Struktur und Lösungseigenschaften von verzweigten diallylesterpolymeren

Abstract

Die topologische Struktur und die Eigenschaften verdiinnter Losungen von verzweigten Polymeren auf Basis von Diallylestern der Sebazin-und Isophthalsaure wurden in einem weiten Bereich der Molekiilmassen untersucht. Die untersuchten Systeme stellen stark verzweigte Polymere dar, die kammartige und statistische Kurzkettenverzweigungen sowie eine groRe Anzahl intramolekularer Cyclen enthalten. In verdunnter Benzenlosung haben die verzweigten Polymere eine untere kritische Mischungstemperatur. In einem guten Losungsmittel weisen die polymeren Knauel sehr niedrige Werte der Grenzviskositat auf. Diese Erscheinungen hangen mit der besonderen topologischen Struktur der untersuchten Systeme zusammen. Topological structure and solution properties of branched diallylester polymersThe topological structure and properties of dilute solutions of branched polymers from diallylesters of sebacic and isophthalic acids have been investigated in a broad interval1 of molecular weights. The systems under study are highly branched polymers containing comblike and random short chain branchings and a large number of intramolecular cyclizations. In dilute solution in benzene the branched polymers exhibit a lower critical mixing temperature. In a good solvent the polymers have a very low intrinsic viscosity. These phenomena are discussed on base of the topological structure ofthe investigated systems.

Monte Carlo Simulation of the Three-Dimensional Free-Radical Polymerization of

“…3. The dependence of the number of cross-links N cr (1,3,5,7) and the number of cycles N cy (2, 4,6,8) on time for UTDSE obtained at: a -l = 1 (1, 2), 2 (3, 4), 3 (5, 6), 4 (7,8); b -l = 7 (1, 2), 10 (3, 4), 14 (5, 6); c -l = 19 (1, 2), 25 (3, 4), 30 (5, 6), 40 (7,8) It is known that with chain elongation the probability of encounters of two ends of this chain in any micro-volume decreases. For molecules of TFM with l = 1, the probability of two ends of this molecule encounters is equal to zero, but in the course of polymerization process there are situations when the two ends of the growing macro-chain come into contact with each other, causing a cycle that is facilitated by the high probability of the reaction of chain termination at radicals contact.…”

“…It gives vivid example about this dependence. Experimental verification of the number of cycles in a three-dimensional polymer is rather scanty and executed, for example, for diallyl derivatives of dicarboxylic acids [7][8][9]. The changes were revealed in the number of cycles for polymers of diallyl sebacinate (DAS) (N cy = 3.8-26.9 for fractions of pre-gel stage with P n = 28.4-191, when P n = 100 N cy = 10-18) and for diallyl isophtalate (DAIPh) (N cy = 2.7-68.4 for fractions pre-gel stage with P n = 7-407, when P n = 100 N cy = 16-34).…”

“…Equation (30b) illustrates the admissibility of the use of more general function for l = (1-40). In [7][8][9] it was estimated the number of branching points in chains of prepolymers of diallyl derivatives. Because each crosslink has two branch points, for cases V and VI we shall receive from 10 to 116 branching points in a row l = 1-40, which significantly exceeds the number of branch points (6-7) to pre-polymers diallyl derivatives, but this fact should not come as a surprise, because in the latter case considered pregel stage, the reactions of chain transfer and other.…”

“…v cr = k cr [R][PG], (7) v cr = k cr [R][PG], (8) v tcr = k tcr [R] 2 , (9) v tcr = k tcr [R][R], (10) v tcr = k tcr [R] 2 , (11) v cy = k cy [R][PG], (12) v cy = k cy [R][PG], (13) v tcy = k tcy [R] 2 , (14) v tcy cy , k tcy are the rate constants of these reactions. As the reactivity of double bonds in M and PG equal and the equality of reaction constant rates was accepted k cr = k cy = k p , k cr = k cy = k p , reactions (7,8,12,13) are among reactions (2, 3); in view of the equality of reactivity of radicals R and R' in reactions (4-6) and in (9)(10)(11)(14)(15)(16)) and equality of the rate constants of reactions k tcr = k tcy = k t , reactions (9-11, 14-16) are included in the reactions (4)(5)(6).…”

“…As the reactivity of double bonds in M and PG equal and the equality of reaction constant rates was accepted k cr = k cy = k p , k cr = k cy = k p , reactions (7,8,12,13) are among reactions (2, 3); in view of the equality of reactivity of radicals R and R' in reactions (4-6) and in (9)(10)(11)(14)(15)(16)) and equality of the rate constants of reactions k tcr = k tcy = k t , reactions (9-11, 14-16) are included in the reactions (4)(5)(6). The possibility of occurrence of this or that elementary reaction of the above mentioned will depend on the probability of encounters (contact) of appropriate reactive centers.…”