聚乳酸立构复合晶体的表面形貌及其力学性能

The Morphology and Mechanical Properties of Poly( Lactic Acid)Stereocomplex Crystal

采用溶液共混法制备了相同质量比的左旋聚乳酸(PLLA)和右旋聚乳酸(PDLA)的立构复合物.采用差示扫描量热仪、偏光显微镜、原子力显微镜、共聚焦显微镜和纳米压痕仪研究了聚乳酸立构复合物晶体的表面形貌及其力学性能的变化.结果表明,样品质量比为1∶1时能够形成立构规整度较高的立构复合晶体;晶体表面出现比较明显的凹陷现象,这是由于结晶后分子链的收缩导致的;样品晶区的硬度和模量相比非晶区有所提升.

The surface morphology and the difference in mechanical properties between crystalline region and amorphous region of the stereocomplex crystal were studied in this paper.The same mass ratio of Poly(L-lactic acid)(PLLA)and poly(D-lactic acid)(PDLA)stereocomplex was prepared by solution blending.Differential Scanning Calorimeter,Polarizing Microscope,Atomic Force Microscope,Confocal Laser Scanning Microscope and Nano Indentation Tester were used to list the surface morphology of PLA stereocomplex crystal and the diversification of mechanical properties.The result showed that a high degree of stereo-tacticity of PLLA/ PDLA blend could be achieved from the mass ratio of 1/1 for sample.The research also showed that obviously depression phenomenon on the surface of crystal was formed due to the contraction of the molecular chain. Furthermore,the hardness and modulus of crystalline region were improved compared to the amorphous region.