当前位置: X-MOL 学术Polym. Int. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Reversible addition–fragmentation chain transfer based copolymers of acrylonitrile and alkyl acrylates as possible precursors for carbon fibers: synthesis and thermal behavior during stabilization
Polymer International ( IF 3.2 ) Pub Date : 2021-08-14 , DOI: 10.1002/pi.6286
Roman V Toms 1 , Mikhail S Balashov 1 , Alexander Y Gervald 1 , Nickolay I Prokopov 1 , Anna V Plutalova 2 , Elena V Chernikova 2, 3
Affiliation  

Copolymers of acrylonitrile and alkyl acrylates with various alkyl substituents (methyl, ethyl, butyl, 2-ethylhexyl and lauryl) were synthesized via reversible addition–fragmentation chain transfer polymerization in dimethylsulfoxide. It is demonstrated that reactivity of alkyl acrylate in copolymerization decreases with increase of the length of the alkyl substituent. The molar fractions of homodiads and homotriads of acrylonitrile and the number-average sequence length of acrylonitrile units decreases with a decrease in the acrylate content in the copolymer or with an increase in the length of the alkyl substituent in the acrylate. The copolymer composition was held constant throughout copolymerization in all the studied systems resulting in the formation of copolymers with high compositional homogeneity. Additionally the reversible addition–fragmentation chain transfer mechanism provides low dispersity of the copolymers. Both factors enable the effect of the alkyl substituent in alkyl acrylate on the thermal behavior of acrylonitrile copolymers to be carefully revealed. Being inert in the cyclization reaction, alkyl acrylates have no effect on the activation energy of the reaction. However, increase of the length of the alkyl substituent is followed by a slower evolution of the ladder structure. In contrast, in conditions of oxidative stabilization, the stabilization index increases in the order of increase of the number-average sequence length of the acrylonitrile units in the copolymers. Thus, the use of alkyl acrylates with longer alkyl substituents provides an increase of chain flexibility and the formation of an enhanced ladder structure during oxidative stabilization which is profitable for carbon fiber production. © 2021 Society of Industrial Chemistry.

中文翻译:

基于可逆加成-断裂链转移的丙烯腈和丙烯酸烷基酯共聚物作为碳纤维的可能前体:稳定过程中的合成和热行为

在二甲亚砜中通过可逆加成-断裂链转移聚合合成了丙烯腈和丙烯酸烷基酯与各种烷基取代基(甲基、乙基、丁基、2-乙基己基和月桂基)的共聚物。结果表明,丙烯酸烷基酯在共聚反应中的反应活性随着烷基取代基长度的增加而降低。丙烯腈的同型二元组和同型三元组的摩尔分数和丙烯腈单元的数均序列长度随着共聚物中丙烯酸酯含量的降低或丙烯酸酯中烷基取代基长度的增加而降低。在所有研究的体系中,共聚物组成在整个共聚过程中保持恒定,从而形成具有高组成均匀性的共聚物。此外,可逆的加成-断裂链转移机制提供了共聚物的低分散性。这两个因素都能够仔细揭示丙烯酸烷基酯中的烷基取代基对丙烯腈共聚物热行为的影响。由于在环化反应中是惰性的,丙烯酸烷基酯对反应的活化能没有影响。然而,随着烷基取代基长度的增加,梯形结构的演变速度较慢。相反,在氧化稳定化条件下,稳定化指数随着共聚物中丙烯腈单元的数均序列长度的增加而增加。因此,使用具有较长烷基取代基的丙烯酸烷基酯增加了链的柔韧性,并在氧化稳定期间形成了增强的梯形结构,这对碳纤维的生产是有利的。© 2021 工业化学学会。
更新日期:2021-08-14
down
wechat
bug