Macromolecular Chain Structure Regulation of AN–MA–IA Aqueous Copolymerization with a Water-Soluble Azo Initiator AIBA,Industrial & Engineering Chemistry Research

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Macromolecular Chain Structure Regulation of AN–MA–IA Aqueous Copolymerization with a Water-Soluble Azo Initiator AIBA
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2021-05-24 , DOI: 10.1021/acs.iecr.1c00997
Tong Qin ₁ , Xun Pan ₂ , Zhenhao Xi ₁ , Ling Zhao _{1,

3} , Weikang Yuan ₁

Affiliation

The performance of acrylonitrile (AN)–methyl acrylate (MA)–itaconic acid (IA) terpolymer is closely related to the uniformity of the sequence structure. In this work, the changes in the dissociative behavior and reactivity of the IA with acidity were examined through calculations based on the density functional theory (DFT). The results of the energy barrier, kinetics, SOMO–LUMO energy gap, and electrostatic repulsion of different dissociated forms demonstrated that the corresponding reactivity between the IA with the AN propagation radical follows the order IA > IA^– > IA^2–, although the IA^– and AN exhibit a similar reactivity. Furthermore, the relationship between the reactivity and dissociated state of the IA monomer was clarified considering the results of the reactivity ratios. A strategy of controlling the sequence structure of polyacrylonitrile (PAN) terpolymers at a stable pH control with the IA^- dissociated state was established. Notably, a water-soluble azo initiator, 2,2′-azobis (2-methylpropionamidine) dihydrochloride (AIBA), was adopted because its initiation process is not related to the pH. AIBA was applied in the aqueous polymerization process to obtain a PAN terpolymer with a relatively uniform chain distribution. The results demonstrated that when the pH value is controlled at 4.7, most of the IA exists in the first-step dissociated form, and its reactivity is comparable to that of monomer AN. In addition, the composition of terpolymer is as follows: 94.96–95.07% of AN, 3.11–3.36% of MA, and 1.68–1.82% of IA, with the raw material ratios being 95:3.2:1.8, indicating the presence of a PAN terpolymer with a uniform chain distribution.

中文翻译：

水溶性偶氮引发剂 AIBA 对 AN-MA-IA 水性共聚的大分子链结构调控

丙烯腈（AN）-丙烯酸甲酯（MA）-衣康酸（IA）三元共聚物的性能与序列结构的均匀性密切相关。在这项工作中，通过基于密度泛函理论 (DFT) 的计算，研究了 IA 与酸度的离解行为和反应性的变化。不同解离形式的能垒、动力学、SOMO-LUMO 能隙和静电排斥的结果表明，IA 与 AN 传播自由基之间的相应反应性遵循 IA > IA ^– > IA ^2–的顺序，尽管 IA ^——和 AN 表现出类似的反应性。此外，考虑到反应性比率的结果，阐明了 IA 单体的反应性和解离状态之间的关系。使用 IA 在稳定的 pH 控制下控制聚丙烯腈 (PAN) 三元共聚物的序列结构的策略^-分离状态成立。值得注意的是，采用了水溶性偶氮引发剂 2,2'-偶氮双（2-甲基丙脒）二盐酸盐（AIBA），因为其引发过程与 pH 值无关。AIBA 应用于水性聚合过程，以获得具有相对均匀链分布的 PAN 三元共聚物。结果表明，当pH值控制在4.7时，大部分IA以一级解离形式存在，其反应性与单体AN相当。此外，三元共聚物的组成如下：AN 94.96-95.07%，MA 3.11-3.36%，IA 1.68-1.82%，原料比为95:3.2:1.8，表明存在具有均匀链分布的 PAN 三元共聚物。

更新日期：2021-06-17

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