Toms Roman V, Ismaylov Daniil A, Gervald Alexander Yu, Prokopov Nickolay I, Plutalova Anna V, Chernikova Elena V
Institute of Fine Chemical Technologies, MIREA-Russian Technological University, pr. Vernadskogo, 86, 119571 Moscow, Russia.
Faculty of Chemistry, Lomonosov Moscow State University, Lenin Hills, 1, bld. 3, 119991 Moscow, Russia.
Polymers (Basel). 2024 Oct 7;16(19):2833. doi: 10.3390/polym16192833.
Binary and ternary copolymers of acrylonitrile (AN), -butyl acrylate (TBA), and -butyl acrylate (BA) are synthesized through conventional radical polymerization in DMSO in the presence of 2-mercaptoethanol. The thermal behavior of binary and ternary copolymers is studied under argon atmosphere and in air. It is demonstrated that the copolymers of AN contain 1-10 mol.% of TBA split isobutylene upon heating above 160 °C, resulting in the formation of the units of acrylic acid in the chain. The carboxylic groups formed in situ are responsible for the ionic mechanism of cyclization, which starts at lower temperatures compared with pure polyacrylonitrile (PAN) or AN copolymer with BA. The activation energy of cyclization through ionic and radical mechanisms depends on copolymer composition. For the ionic mechanism, the activation energy lies in the range ca. 100-130 kJ/mole, while for the radical mechanism, it lies in the range ca. 150-190 kJ/mole. The increase in the TBA molar part in the copolymer is followed by faster consumption of nitrile groups and the evolution of a ladder structure in both binary and ternary copolymers. Thus, the incorporation of a certain amount of TBA in PAN or its copolymer with BA allows tuning the temperature range of cyclization. This feature seems attractive for applications in the production of melt-spun PAN by choosing the appropriate copolymer composition and heating mode.
通过在二甲基亚砜（DMSO）中，在2-巯基乙醇存在下进行常规自由基聚合反应，合成了丙烯腈（AN）、丙烯酸叔丁酯（TBA）和丙烯酸丁酯（BA）的二元和三元共聚物。在氩气气氛和空气中研究了二元和三元共聚物的热行为。结果表明，AN共聚物在加热至160℃以上时，含有1-10摩尔％的TBA会分解异丁烯，从而在链中形成丙烯酸单元。原位形成的羧基负责环化的离子机制，与纯聚丙烯腈（PAN）或AN与BA的共聚物相比，该机制在较低温度下开始。通过离子和自由基机制进行环化反应的活化能取决于共聚物的组成。对于离子机制，活化能约为100-130kJ/mol，而对于自由基机制，活化能约为150-190kJ/mol。共聚物中TBA摩尔含量的增加伴随着腈基的更快消耗以及二元和三元共聚物中梯形结构的形成。因此，在PAN或其与BA的共聚物中引入一定量的TBA可以调节环化的温度范围。通过选择合适的共聚物组成和加热方式，这一特性对于熔纺PAN的生产应用似乎具有吸引力。
