Zhang Zuxin, Zhang Daihui, Fu Gaowei, Wang Chunpeng, Chu Fuxiang, Chen Riqing
Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry; National Engineering Laboratory for Biomass Chemical Utilization; Key Laboratory of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; Key Laboratory of Biomass Energy and Material, Nanjing 210042, China.
Polymers (Basel). 2020 Jan 2;12(1):80. doi: 10.3390/polym12010080.
As a chain transfer agent, 2,4-diphenyl-4-methyl-1-pentene (αMSD) was first introduced in the emulsion binary copolymerization of methyl methacrylate (MMA) and butyl acrylate (BA) based on an irreversible addition-fragmentation chain transfer (AFCT) mechanism. The effects of αMSD on molecular weight and its distribution, the degree of polymerization, polymerization rate, monomer conversion, particle size, and tensile properties of the formed latexes were systematically investigated. Its potential chain transfer mechanism was also explored according to the H NMR analysis. The results showed that the increase in the content of αMSD could lead to a decline in molecular weight, its distribution, and the degree of polymerization. The mass percentage of MMA in the synthesized polymers was also improved as the amounts of αMSD increased. The chain transfer coefficients of αMSD for MMA and BA were 0.62 and 0.47, respectively. The regulation mechanism of αMSD in the emulsion polymerization of acrylates was found to be consistent with Yasummasa's theory. Additionally, monomer conversion decreased greatly to 47.3% when the concentration of αMSD was higher than 1 wt% due to the extremely low polymerization rate. Moreover, the polymerization rate was also decreased probably due to the desorption and lower reactivity of the regenerative radicals from αMSD. Finally, the tensile properties of the resulting polyacrylate films were significantly affected due to the presence of αMSD.
作为链转移剂，2,4 - 二苯基 - 4 - 甲基 - 1 - 戊烯（αMSD）首次基于不可逆加成 - 断裂链转移（AFCT）机理引入到甲基丙烯酸甲酯（MMA）和丙烯酸丁酯（BA）的乳液二元共聚合反应中。系统研究了αMSD对形成的胶乳的分子量及其分布、聚合度、聚合速率、单体转化率、粒径和拉伸性能的影响。还根据核磁共振氢谱（¹H NMR）分析探索了其潜在的链转移机理。结果表明，αMSD含量的增加会导致分子量、其分布以及聚合度下降。随着αMSD用量的增加，合成聚合物中MMA的质量百分比也有所提高。αMSD对MMA和BA的链转移系数分别为0.62和0.47。发现αMSD在丙烯酸酯乳液聚合中的调控机理与安政正的理论一致。此外，当αMSD浓度高于1 wt%时，由于聚合速率极低，单体转化率大幅降至47.3%。而且，聚合速率下降可能是由于αMSD再生自由基的解吸和较低的反应活性。最后，由于αMSD的存在，所得聚丙烯酸酯薄膜的拉伸性能受到显著影响。
