两亲性聚乳酸嵌段共聚物的制备及性能研究

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粘度和吸水率的影响。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。

Synthesis and properties of amphiphilic block polylactide copolymers

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