聚乳酸/聚丙二醇多嵌段共聚物的合成及表征

Synthesis and characterization of poly(lactic acid)-poly(propylene glycol)multiblock copolymer

以乳酸为原料,通过缩合聚合合成了齐聚乳酸(OLA);以1,6-己二异氰酸酯为扩链剂,扩链OLA和聚丙二醇(PPG)得到多嵌段共聚物(OLA-b-PPG)。采用核磁共振氢谱(1 H-NMR)、傅里叶红外光谱(FT-IR)表征嵌段共聚物的结构;由凝胶渗透色谱(GPC)测定嵌段共聚物的分子量及分子量分布;采用热重分析法(TGA)和示差扫描量热法(DSC)对聚合物的热性能进行了表征;通过拉伸实验测试了聚合物的力学性能。结果表明:OLA和PPG能够通过1,6-己二异氰酸酯扩链制得多嵌段共聚物OLA-b-PPG。OLA-b-PPG的重均分子量为33463g/mol,分子量分布为1.93。与OLA相比,OLA-b-PPG熔点降低,为126℃。OLA-b-PPG的断裂强度为12.2±0.3MPa,断裂延伸率为(3.5±0.5)%。

Oligo（lactic acid）was synthesized by condensation polymerization.Using HDI as chain extender,oligo（lactic acid）-b-poly（propylene glycol）multiblock copolymer（OLA-b-PPG）was synthesized via melt polymerization.The resultant copolymer structure was characterized by nuclear magnetic resonance and fourier transform infrared spectrum,and the molecular weight and its distribution of OLA-b-PPG were characterized by GPC.The melting temperature of OLA-bPPG was 126℃.The tensile strength and elongation at break of OLA-b-PPG were 12.2±0.3MPa and（3.5±0.5）%,respectively.