Yao Fangjun, Liu Qingqing, Zhang Zhengbiao, Zhu Xiulin
Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China.
Polymers (Basel). 2017 Mar 3;9(3):89. doi: 10.3390/polym9030089.
The impacts of hydrogen bonding on polymerization behavior has been of interest for a long time; however, universality and in-depth understanding are still lacking. For the first time, the effect of hydrogen bonding on the classical alternating-type copolymerization of styrene and maleimide was explored. N-phenylmaleimide (N-PMI)/styrene was chosen as a model monomer pair in the presence of hydrogen bonding donor solvent 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), which interacted with N-PMI via hydrogen bonding. Reversible addition-fragmentation chain transfer polymerization (RAFT) technique was used to guarantee the "living" polymerization and thus the homogeneity of chain compositions. In comparison with the polymerization in nonhydrogen bonding donor solvent (toluene), the copolymerization in HFIP exhibited a high rate and a slight deviation from alternating copolymerization tendency. The reactivity ratios of N-PMI and St were revealed to be 0.078 and 0.068, respectively, while the reactivity ratios in toluene were 0.026 and 0.050. These interesting results were reasonably explained by using computer simulations, wherein the steric repulsion and electron induction by the hydrogen bonding between HFIP and NPMI were revealed. This work first elucidated the hydrogen bonding interaction in the classical alternating-type copolymerization, which will enrich the research on hydrogen bonding-induced polymerizations.
氢键对聚合行为的影响长期以来一直备受关注；然而，其普遍性和深入理解仍显不足。首次探究了氢键对苯乙烯与马来酰亚胺经典交替型共聚反应的影响。在氢键供体溶剂1,1,1,3,3,3 - 六氟 - 2 - 丙醇（HFIP）存在的情况下，选择N - 苯基马来酰亚胺（N - PMI）/苯乙烯作为模型单体对，HFIP通过氢键与N - PMI相互作用。采用可逆加成 - 断裂链转移聚合（RAFT）技术来确保“活性”聚合，从而保证链组成的均匀性。与在非氢键供体溶剂（甲苯）中的聚合反应相比，在HFIP中的共聚反应速率较高，且与交替共聚倾向略有偏差。N - PMI和苯乙烯的竞聚率分别为0.078和0.068，而在甲苯中的竞聚率分别为0.026和0.050。通过计算机模拟对这些有趣的结果进行了合理的解释，其中揭示了HFIP与NPMI之间氢键的空间排斥和电子诱导作用。这项工作首次阐明了经典交替型共聚反应中的氢键相互作用，这将丰富对氢键诱导聚合反应的研究。
