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温度敏感性PNIPAM-b-PZLL-b-mPEG三嵌段共聚物的合成与自组装研究

ISSN号：1000-3304
期刊名称：《高分子学报》
时间：0
分类：O632.13[理学—高分子化学;理学—化学] O633.22[理学—高分子化学;理学—化学]
作者机构：[1]中国科学院长春应用化学研究所高分子物理与化学国家重点实验室,长春130022, [2]中国科学院研究生院,北京100039
相关基金：国家自然科学基金（基金号50573078）、杰出青年基金（基金号50425309）、重点基金（基金号50733003）和科技部国际合作重大项目（项目号2007DFR5020）资助项目;

关键词：聚(N-异丙基丙烯酰胺), 聚(ε-苄氧羰基-L-赖氨酸), 聚乙二醇单甲醚, 温度敏感性, 胶束, Poly（N-isopropylacrylamide）,Poly（3-benzyloxycarbonyl-L-lysine）,mPEG,Temperature sensitivity,Micelle,Self-assembly

中文摘要：

通过大分子引发剂引发ε-苄氧羰基-L-赖氨酸-N-羧酸酐（Lys-NCA）开环聚合和大分子缩合的方法合成了聚（N-异丙基丙烯酰胺）-b-聚（ε-苄氧羰基-L-赖氨酸）-b-聚乙二醇单甲醚三嵌段共聚物（PNIPAM-b-PZLL-b-mPEG）.用GPC和^1H-NMR对其结构进行了表征.用芘荧光探针法证明了该三嵌段聚合物形成胶束的性质并测定了临界胶束浓度（CMC）.动态光散射（DLS）研究表明,在固定PNIPAM-b-PZLL链段长度的情况下,mPEG分子量为2000时,胶束在温度高于临界溶解温度（LCST）时发生聚集,mPEG分子量为5000时,胶束在LCST以上没有发生聚集.

英文摘要：

A novel amphiphilic and thermosensitive triblock copolymer of poly（N-isopropylacrylamide）-b-poly（3-benzyloxycarbonyl-L-lysine）-b-poly（ethylene glycol）（PNIPAM-b-PZLL-b-mPEG） with designed molecular weight and narrow molecular weight distribution was prepared.Synthetic procedure included the following steps.（1） Amino-terminated PNIPAM was synthesized via the free radical polymerization of NIPAM in methanol using 2,2＇-azobisiso-butyronitrile（AIBN） and 2-aminoethanethiol hydrochloride（AET·HCl） as the initiator and chain transfer agent,respectively.Its molecular weight was calculated by the 1H-NMR spectra in D2O.（2） The block copolymers,PNIPAM-b-PZLL were synthesized by the ring-opening polymerization（ROP） of 3-benzyloxycarbonyl-L-lysine N-carboxyanhydride（Z-Lys-NCA） with PNIPAM-NH2 as a macroinitiator.Their structure was confirmed by the ^1H-NMR spectra.The molecular weight and molecular weight distribution of PNIPAM-b-PZLL were characterized by GPC analysis in THF.The relatively narrow polydispersity of the obtained PNIPAM-b-PZLL could be explained by the living character of the ROP of NCAs initiated by primary amine hydrochlorides which avoided the side reaction called ＂active monomer＂ mechanism.Generally,the molecular weights could be controlled by the feed molar ratios of monomer to maroinitiator.（3） For preparing the triblock polymers,PNIPAM-b-PZLL-b-mPEG,it was necessary to convert the terminal hydroxyl group of mPEG of different molecular weight（2000 or 5000） into carboxyl group by succinic anhydride.Its ^1H-NMR spectra showed this was a high efficiency reaction.Then the triblock copolymers were obtained by the condensation reaction between carboxyl-capped mPEG and amino-capped PNIPAM-b-PZLL in the presence of dicyclohexylcarbodiimide（DCC） and 4-dimethylaminopyridine（DMAP）.The ^1H-NMR confirmed their structure.Based on the integration ratio,their relative amount in the copolymer was calculated.And their Mn（NMR） agreed well with the theoretical