中文摘要：

目的由于PLLA合成分子量低、疏水性强、韧性差、细胞相容性不佳,通过对PLLA改性,进一步改善其亲水性、血液相容性。方法以L-乳酸（L-LA）为单体,季戊四醇为扩链剂,辛酸亚锡为催化剂,在微波辐射作用下通过熔融缩聚开环聚合的方法合成了具有星形结构的聚L-乳酸（s-PL-LA）;通过合成的s-PLLA与甲基丙烯酸酐（MAAH）的接枝反应,制备了具有甲基丙烯酸酯基的PLLA聚合物（PLLA-MAAH）。通过凝胶渗透色谱（GPC）、核磁共振（NMR）、傅里叶变换红外光谱（FTIR）、差示扫描量热（DSC）、X射线衍射（XRD）、粉末法动态接触角（DCAT）测试等手段对合成的s-PLLA和PLLA-MAAH的相对分子质量、结构与性能等进行了表征。结果由L-乳酸单体合成的聚合物为星形结构s-PLLA,s-PLLA与MAAH接枝反应后形成一个末端多官能团的聚合物PL-LA-MAAH。结论相比于s-PLLA,PLLA-MAAH相对分子质量增加,亲水性增强。

英文摘要：

Aim Poly（L-lactic acid）（PLLA） polymers have low molecular weight,strong hydrophobicity,poor toughness and poor biocompatibility.Therefore,it is of great importance for biological applications for us to regulate the performances of the PLLA,and further improve its hydrophilicity and blood compatibility by mediating the PLLA.Methods Synthesizing star-shaped poly（L-lactide acid）（s-PLLA） by a melting polycondensation open-ring polymerization route in condition of microwave irradiation using lactic acid as monomer.Achieving PLLA-MAAH by grafting methacrylic anhydride（MAAH） onto the s-PLLA.The molecular structure,the molecular weight and performances of the as-synthesized polymers are characterized by means of gel permeation chromatography（GPC）,nuclear magnetic resonance（NMR）,Fourier transform infrared spectroscopy（FTIR）,differential scanning calorimetry（DSC）,X-ray diffraction（XRD） and dynamic contact angle test（DCAT）,etc.Results The experimental results show that the as-synthesized PLLA is confirmed to be star-shaped and the PLLA-MAAH is a multifunctional terminated polymer.Conclusion Compared to the s-PLLA,the PLLA-MAAH polymer exhibits increased molecular weight and improved hydrophilicity.