两亲性聚乳酸嵌段共聚物的制备及性能研究

Synthesis and properties of amphiphilic block polylactide copolymers

以端羟基聚乳酸和α-溴代丙酰溴为原料,制备了溴端基的聚乳酸;再以其为大分子引发剂,以溴化亚铜/2,2’-联吡啶为催化体系进行N-乙烯基吡咯烷酮的原子转移自由基聚合,制得了两亲性聚乳酸嵌段共聚物。用IR、GPC对聚合物进行了表征,用接触角测定仪测定了聚合物薄膜的水接触角,并考察了不同反应时间对共聚物的特性黏度和吸水率的影响。结果表明,该聚乳酸共聚物的亲水性较聚乳酸均聚物明显增大,TEM证实共聚物在水相中可形成一壳多核球状胶束,进一步佐证了该共聚物具有明显的两亲性。

Novel amphiphilic block copolymers of poly-N-vinylpyrrolidone and poly （D, L-tactide） were synthesized by atom transfer radical polymerization using N-vinylpyrrolidone as the monomer and a polylactideterminated with bromine, which was prepared by reaction of a hydroxy-terminated polylactide oligomer with α-bromopropanoyl bromide in the presence of a CuBr/2, 2＇-bipyridine catalyst, as a functional macromolecular initiator. The products were characterized by IR and GPC. The properties and morphology of the copolymers were determined by contact angle and water take-up measurements and by TEM. The results showed that introduction of the PVP chain markedly enhances the surface hydrophilicity of the copolymers and the amphiphilic polymer can self-assemble into a core-shell structure （polymer micelle）.