文献类型：期刊文献

中文题名：中间体自由基断裂对丙烯酸甲酯/甲基丙烯酸甲酯RAFT聚合的影响

英文题名：Study of radical intermediate cleavage on RAFT polymerization of methyl acrylate and methyl methacrylate

作者：吴宇辉[1];张家龙[2];侯远赫[2];刘振[1]

机构：[1]华东理工大学化工学院,上海200237;[2]中石化(上海)石油化工研究院有限公司,上海201208

年份：2025

卷号：76

期号：10

起止页码：5464

中文期刊名：化工学报

外文期刊名：CIESC Journal

收录：;EI(收录号：20254919637374);北大核心:【北大核心2023】；

语种：中文

中文关键词：可逆加成-断裂链转移聚合;丙烯酸甲酯;甲基丙烯酸甲酯;机理;自由基

外文关键词：RAFT polymerization;methyl acrylate;methyl methacrylate;mechanism;radical

摘要：丙烯酸甲酯(MA)与甲基丙烯酸甲酯(MMA)虽具有相似的单体结构,但在可逆加成-断裂链转移(RAFT)控制的聚合反应中常表现出显著的行为差异。通过对比4种不同链转移剂(CTA),重点揭示了MA与MMA在RAFT聚合中关于分子量控制及多分散指数差异的内在机制。结合聚合动力学实验与密度泛函理论(DFT)计算,重点分析了中间体自由基的断裂倾向(φ)及CTA与增长自由基间的相互作用强度(控制指数C)。实验结果表明,中间体自由基的解离倾向及其与CTA的作用强度是影响聚合速率和分子量分布的关键因素。当φ趋近于1时(如MA/CTA 2-4体系),分子量与理论值吻合良好;而在MMA体系中,由于甲基对P_(n)·自由基的稳定作用导致R·解离受阻(φ趋近于0),初期分子量显著偏离理论值,后续通过短链再生逐步降低偏离。本研究为RAFT聚合中分子量预测的异常行为提供了实验与理论解释,对RAFT聚合的精确控制具有指导意义。
Although methyl acrylate(MA)and methyl methacrylate(MMA)share similar monomer structures,they exhibit significant behavioral differences in reversible addition-fragmentation chain transfer(RAFT)polymerization.This study focuses on investigating the intrinsic mechanisms underlying the differences in molecular weight control and dispersity between MA and MMA by comparing four distinct chain transfer agents(CTAs).Combining polymerization kinetics experiments with density functional theory(DFT)calculations,the fragmentation tendency(φ)of intermediate radicals and the interaction strength between CTAs and propagating radicals(control index,C)were analyzed.The results show that the dissociation tendency of the intermediate free radical and its interaction strength with CTA are key factors affecting the polymerization rate and molecular weight distribution.Whenφapproaches 1(e.g.,in MA/CTA 2-4 systems),the molecular weight aligns well with theoretical predictions.In contrast,for MMA systems,the stabilization of P_(n)·radicals by the methyl group hinders R·dissociation(φapproaches 0),leading to significant deviations from theoretical molecular weights in the early stages,which are gradually reduced through short-chain regeneration.This study provides experimental and theoretical insights into the anomalous molecular weight prediction behavior in RAFT polymerization,offering valuable guidance for the precise control of RAFT systems.