用原位核磁研究苯乙烯与马来酸酐的RAFT共聚合

Application of in situ NMR in research of RAFT-mediated styrene-maleic anhydride copolymerization

利用液体核磁共振波谱仪原位跟踪苯乙烯与马来酸酐的可逆加成-断裂链转移(RAFT)聚合,探讨了RAFT聚合的活性可控行为。实验证明了RAFT的高度选择性,推测了苯乙烯与马来酸酐共聚合时电子转移络合物机理的合理性,并对反应阶段进行了较详细的描述。单体的消耗、第一个单体及第二个单体的插入有较为直观的谱图处理。实验中,苯乙烯与马来酸酐的摩尔比为2∶1,反应过程分为两个阶段,开始是两种单体的交替共聚合,马来酸酐消耗完后即发生苯乙烯的均聚合,最终得到苯乙烯-马来酸酐共聚物与聚苯乙烯的两嵌段聚合物。

1H nuclear magnetic resonance(NMR)spectrometer was used to investigate the in-situ reversible addition-fragmentation chain transfer(RAFT)polymerization of maleic anhydride and styrene.The controlled activities of RAFT polymerization were observed as well.It is found that the reaction is extremely selective.The mechanism of the electron transfer complex in the copolymerization and the stages of the reaction were explored.The consumption of monomer and the addition of the first and second monomer are reflected by spectra.The mole ratio of styrene and maleic anhydride is 2∶1.The alternating copolymerization is boosted up in the first stage of the reaction.When maleic anhydride is consumed up,the homo-polymerization of styrene continues to produce copolymer of poly(styrene-alternative-maleic anhydride)-b-polystyrene.