成核剂对聚乳酸结晶及力学性能的影响

摘要

采用熔融共混法,用成核剂对聚乳酸(PLA)进行成核改性.通过差示扫描量热仪(DSC)、X射线衍射仪(XRD)、偏光显微镜(PLM)及力学性能和热变形温度(HDT)等测试,研究成核剂对PLA的结晶、力学和耐热性能的影响.结果表明:改性PLA的结晶温度和结晶度提高,晶体尺寸减小,且PLA的晶型结构没有改变；改性PLA的拉伸强度、拉伸屈服强度和刚性降低,韧性有所提高；将注射成型的改性PLA样条进行退火处理后,耐热性有很大提高.%PLA was modified by the nucleating agent using melting blending method. The effect of the nucleating agent on crystallization behaviors, mechanical properties and heat resistance of PLA were investigated by means of DSC, XRD, PLM, mechanical and HDT tests. It is found that the crystallization temperature and crystallinity increase. The spherulitic size decreases for the nucleated PLA, but the crystal structure of the nucleated PLA is not changed. The tensile strength, tensile yield strength and rigidity of the modified PLA decrease, the toughness increases. When the injection molded modified PLA specimens are annealed, the heat resistance is greatly improved.