Abstract

The copolymers of acrylonitrile and acrylic acid are synthesized for the first time by trithiocarbonate-mediated reversible addition-fragmentation chain transfer polymerization in DMSO at a content of comonomers in the reaction mixture of 40%. Various regimes of acrylic acid introduction into the reaction are tested. This makes it possible to synthesize copolymers with close average composition and different unit distribution in a chain. It is shown that, with an increase in the fraction of acrylic acid in the copolymer, the contribution of the ionic mechanism of cyclization grows, which is favorable for widening the temperature interval of cyclization and decrease in the intensity of heat flow. Reduction in the rate of introduction of acrylic acid into copolymerization and, as a consequence, its more uniform distribution in the chain lead to analogous effects and cause a decrease in the activation energy of cyclization by both the ionic and radical mechanism. Thus, the use of reversible addition-fragmentation chain transfer polymerization with the dosed introduction of the comonomer allows one to tune the properties of the copolymers during their heat treatment.

中文翻译：

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丙烯腈和丙烯酸的共聚物：链单元的组成和分布对共聚物热行为的影响

摘要

通过三硫代碳酸酯介导的可逆加成-断裂链转移聚合反应，在DMSO中以40％的共聚单体含量首次合成丙烯腈和丙烯酸的共聚物。测试了将丙烯酸引入反应的各种方式。这使得可以合成具有接近平均组成且链中单元分布不同的共聚物。结果表明，随着共聚物中丙烯酸含量的增加，环化离子机理的贡献增加，有利于拓宽环化温度区间，降低热流强度。降低丙烯酸共聚的速率，因此，其在链中更均匀的分布会导致类似的效果，并通过离子和自由基机理降低环化的活化能。因此，可逆的加成-断裂链转移聚合和共聚单体的定量引入的使用允许人们在共聚物的热处理过程中调节其性能。