【摘要】 利用溶液13C NMR和HMBC实验对AB型两亲性嵌段共聚物单甲氧基聚乙二醇-聚(己内酯-co-丙交酯)[MeOPEG-P(Cap-co-LL)]的嵌段结构以及聚(己内酯-co-丙交酯)[P(Cap-co-LL)]嵌段中Cap和LL的无规结构进行了表征.研究发现,P(Cap-co-LL)中Cap、LL的组成对P(Cap-co-LL)的无规度、Cap和LL的酯交换程度以及不同组分的平均链长均有影响.对LL中立体结构不同所产生的酯交换也进行了表征.更多还原

【Abstract】 In this paper, a AB type of amphiphilic diblock copolymer, composed of methoxy-poly(ethylene glycol) (MeOPEG) as the hydrophilic block and poly(ε-caprolactone-co-d,l-lactide) (P(Cap-co-LL)) as the hydrophobic block were synthesized by bulk ring-opening copolymerization using MeOPEG as initiator and LL and Cap as comonomers. The chemical structure of the diblock copolymer MeOPEG-P(Cap-co-LL) was studied by 1H NMR, 13C NMR and HMBC. It was found that random copolymerization of Cap and LL occurred in the formation of P(Cap-co-LL) blocks. The transesterification behavior between the Cap units and the LL units and that between the d-lactide unit and the l-lactide unit in P(Cap-co-LL) were investigated. The yield of the transesterification, the randomness of P(Cap-co-LL) blocks and the average length of caproyl segments and lactidyl segments were calculated using the Bernoulli statistics theory and 13C NMR spectra. It was found that both the yield of the transesterification and the randomness of P(Cap-co-LL) block were the highest when the mass ratio of LL to Cap was close to 1∶1. It was also shown that the synthesis condition and the feeding ratio of P(Cap-co-LL) segments have important influences on the transesterification extent, randomness of P(Cap-co-LL) blocks and the average length of caproyl segments and lactidyl segments.更多还原