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为改善聚乳酸的亲水性 ,以辛酸亚锡为催化剂 ,自制的D ,L -丙交酯和低相对分子质量端羟基聚乙烯基吡咯烷酮 (PVP)为单体 ,采用本体开环嵌段共聚合法 ,制备了两亲性聚乳酸 -PVP双嵌段共聚物。考察了原料配比对共聚物的黏均相对分子质量及在磷酸盐缓冲液中的降解规律的影响 ,并测定了其接触角和吸水率。结果表明 ,随PVP用量增大 ,共聚物相对分子质量下降 ,但降解速率增大 ,表明在聚乳酸中引入PVP链段可使聚合物的亲水性得到很大提高。
In order to improve the hydrophilicity of polylactic acid, self - made D, L - lactide and low molecular weight hydroxyl terminated poly (vinyl pyrrolidone) (PVP) were prepared by the ring - opening block copolymerization Legally, amphipathic polylactic acid-PVP diblock copolymer was prepared. The effects of the ratio of raw materials on the viscosity-average molecular weight and the degradation of the copolymer in phosphate buffer solution were investigated. The contact angle and water absorption were measured. The results showed that with the increase of PVP, the relative molecular weight of copolymer decreased, but the degradation rate increased, which indicated that the introduction of PVP segment in polylactic acid could greatly improve the hydrophilicity of the polymer.