伯胺引发NNTA开环聚合对水的耐受性研究  

Water Tolerated Polymerization of N-Substituted Glycine N-Thiocarboxyanhydride Initiated by Primary Amines

作　　者：郑博拓 陶鑫峰[1] 凌君[1] 

机构地区：[1]教育部高分子合成与功能构造重点实验室浙江大学高分子科学与工程学系,杭州310027

出　　处：《高分子学报》2018年第1期72-79,共8页Acta Polymerica Sinica

基　　金：国家重点基础研究发展计划(973计划;项目号2014CB931900);国家自然科学基金(基金号21674091;21528402)资助项目

摘　　要：研究了苄胺引发N-取代甘氨酸-N-硫代羧酸酐(NNTA)开环聚合.聚合对引发剂当量的水(100~600μg/g)具有很好的耐受性,能保持良好的可控性,聚类肽产率高(>70%),分子量可控(1600~7500),分子量分布较窄(1.13~1.25).随着水含量的增加(达到单体当量)(14000μg/g),聚合产率与产物分子量均有不同程度的下降.MALDI-To F质谱证明所得聚类肽均为苄胺引发产物,水不能引发NNTA聚合.聚合动力学实验表明该聚合体系表现出准一级动力学反应的特征,在不同单体转化率时,聚合物数均分子量与单体转化率呈线性关系,分子量分布窄,证明该聚合体系具有可控性.进一步地,使用未经除水精制处理的市售THF溶剂和未经烘烤除水的反应瓶进行NNTA聚合反应,也表现出很好的可控性.NNTA单体易合成、易储存,聚合时不受微量水的影响,极大地降低了聚类肽的合成难度,有利于聚类肽材料的推广与应用.N-Substituted glycine N-carboxyanhydride（NNCA） polymerization cannot tolerate H2 O, because the presence of H2 O leads to oligopolymerization or deterioration of NCA. In contrast, its analogue N-substituted glycine N-thi℃arboxyanhydride（NNTA） is stable to H2 O. In this work, by comparing 1 H-NMR spectra signal of NNTA with that of internal standard（trioxane, TOX） before and after heating for 24 h in presence of water, it is shown the tolerance of NNTA to water amount was monomer-equivalent（14000 μg/g）. The polymerization of NNTA initiated by benzylamine was carried out in presence of water. ~1H-NMR, MALDI-To F-MS and SEC were used to confirm the structure of polypeptoid products. The polymerization of N-ethyl glycine NTA（NEG-NTA） initiated by benzylamine showed good tolerance to initiator-equivalent water amount（100-650 μg/g）. From this polymerization, high yield（ 70%） was obtained with controlled molecular weights（1600-7500） and low molecular weight distribution（PDI, i.e. polydispersity index： 1.22-1.25）. Increasing amount of water（14000 μg/g） suppressed the polymerization, resulting in low yields and low molecular weights to some extent, while PDI remained low. All polymers contained benzylamine end group according to MALDI-To F-MS, which demonstrated that all the polymerization of NNTA followed the normal amine mechanism（NAM） regardless of different water contents. Polymerizations of sarcosine NTA（Sar-NTA） and N-butyl glycine NTA（NBG-NTA） in presence of initiator-equivalent water amount were also investigated. Polymerization of sarcosine NTA resulted in high yield（89%） with controlled molecular weight and low PDI（1.13）, which showed that the polymerization of NNTA with higher activity was more tolerant to water. Furthermore, the polymerization kinetics confirmed the controllability of the resulting polymer by demonstrating that the polymerization followed pseudo-first order kinetics with regard to monomer up to high conversion（~ 90%）. In ad

关 键 词：类肽 聚-α-氨基酸 聚-N-取代甘氨酸 氨基酸-N-硫代羧酸酐 开环聚合 

分 类 号：O631.5[理学—高分子化学]