Chinese Journal of Polymer Science ( IF 4.1 ) Pub Date : 2023-05-18 , DOI: 10.1007/s10118-023-2989-0 Yan-Xin Zhang , Dong Chen , Gao-Fei Hu , Yu-Hong Ma , Wan-Tai Yang
The alternating copolymerization of hydroxyalkyl vinyl ethers and dialkyl maleates is investigated by conventional radical polymerization and reversible addition-fragmentation chain transfer polymerization (RAFT). The influence of comonomer structure, comonomer feeding ratios, and monomer concentrations on the copolymerization and the copolymer structure have been investigated systematically. With 2-hydroxyethyl vinyl ether (HEVE) and dimethyl maleates (DMM) as comonomers, a well-defined alternating copolymer is prepared with Mn=3400 and Mw/Mn=1.93 up to 71.6% monomer. The alternating sequential chain structure of the copolymers has been proved by both NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The experimental reactivity ratios and theoretical calculated highest occupied molecular orbital and the lowest unoccupied molecular orbital of vinyl ethers and alkyl maleates support that these monomer pairs have tendency to form alternating copolymers. With 2-cyanopropan-2-yl N-methyl-N-(pyridin-4-yl)carbamodithioate as the RAFT agent, the molecular weight of HEVE and DMM copolymer increases with the monomer conversion, demonstrating a controlled radical polymerization feature with well-controlled molecular weight and relatively narrower molecular weight distribution. With alternating copolymer of HEVE and DMM as macro-CTA (Mn=5200 and Mw/Mn=1.46), both the chain extension with HEVE and DMM (Mn=10400 and Mw/Mn=1.72) and block copolymerization with vinyl acetate have been successfully achieved (Mn=8500 and Mw/Mn=1.52).
中文翻译:
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羟烷基乙烯基醚与马来酸二烷基酯的常规自由基和 RAFT 交替共聚
通过常规自由基聚合和可逆加成断裂链转移聚合(RAFT)研究了羟烷基乙烯基醚和马来酸二烷基酯的交替共聚。系统地研究了共聚单体结构、共聚单体投料比和单体浓度对共聚和共聚物结构的影响。以2-羟乙基乙烯基醚(HEVE)和马来酸二甲酯(DMM)为共聚单体,制备了Mn = 3400、Mw / Mn =1.93 、单体含量高达71.6%的结构明确的交替共聚物。NMR 和基质辅助激光解吸/电离飞行时间质谱 (MALDI-TOF MS) 证明了共聚物的交替顺序链结构。乙烯基醚和马来酸烷基酯的实验反应率和理论计算的最高占据分子轨道和最低未占据分子轨道支持这些单体对具有形成交替共聚物的倾向。以 2-氰基丙烷-2-基N-甲基-N- (吡啶-4-基)二硫代氨基甲酸酯作为 RAFT 试剂,HEVE 和 DMM 共聚物的分子量随着单体转化率的增加而增加,表现出受控的自由基聚合特征,并且具有良好的稳定性。可控的分子量和相对较窄的分子量分布。以HEVE和DMM的交替共聚物作为大分子CTA(M n = 5200和M w / Mn = 1.46),既用HEVE和DMM(M n = 10400和M w / Mn = 1.72)进行扩链和嵌段与乙酸乙烯酯的共聚已成功实现(M n = 8500和M w / M n = 1.52)。