亲水性聚乳酸嵌段共聚物制备及表征

Synthesis and Characterization of Hydrophilic Tri-block Polylactide Copolymer

为改善聚乳酸的亲水性,采用自制的OH-PLA-OH和CAC为原料,制备Cl-PLA-Cl,以此作为大分子引发剂、以CuBr/2,2’-联吡啶为催化体系进行NVP的ATRP,制备三嵌段共聚物PVP-b-PLA-b-PVP.研究了制备PVP-b-PLA-b-PVP的最佳反应物用量及共聚物的亲水性与降解性能.结果表明,反应物料的最佳用量为Cl-PLA-Cl 4.17 g,NVP 11.12 g,CuBr0.29 g,2,2’-联吡啶0.62 g,环己酮30 mL.PVP-b-PLA-b-PVP的亲水性较PLA有明显提高.共聚物在NaOH溶液中的降解速率最快,磷酸盐缓冲液中最慢.该方法是改善聚乳酸亲水性的一条较好的途径.

Novel hydrophilic tri-block copolymers of poly-N-vinylpyrrolidone and polylactide were synthesized by ATRP using Nvinylpyrrolidone as the monomer and polylactideterminated with chlorides as the functional macroinitiator, which was prepared by reacting the hydroxyls-terminated polylactide oligomer with chloroacetic chloride in the presence of CuBr/2, 2＇-bipyridine as catalyst. The hydrophilicity and the degradability of the copolyrner films were investigated. The results showed that the hydrophilicity of the copolymer was much higher than that of PLA homo-polymer. The target copolymers PVP-b-PLA-b-PVP was degraded more rapidly than PLA. The degradation of copolymer in NaOH solution was more rapidly than in HCI solution, H2O and phosphate buffer solution. This method was a good way to improve PLA＇s hydrophilicity.