摘要
以埃洛石纳米管(HNT)为成核剂,使用双螺杆挤出机通过熔融-骤冷工艺制备聚乳酸(PLA)/HNT复合材料,并采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、差式扫描量热仪(DSC)、偏光显微镜(POM)及计算机控制拉力试验机对其性能进行分析。断面形貌分析结果表明HNT的加入使PLA断面的粗糙度增加,断裂方式由纹源断裂转变为孔洞断裂;结晶行为分析表明,熔融-骤冷工艺制备的PLA/HNT复合材料结晶度极低,添加HNT未改变PLA的晶型,退火能够有效促进PLA结晶的完善;降温速率对PLA的结晶行为影响极大,10℃/min与2℃/min降温过程及其第二次升温过程都存在着显著的差异,低降温速率更有利于PLA进行结晶; HNT能够发挥异相成核的作用,降低成核壁垒,提高PLA的结晶度,当HNT的质量分数为1. 2%时,复合材料的结晶度较纯PLA提高了40. 98%,且球晶的尺寸显著减小;力学性能分析表明,HNT的加入降低了PLA的拉伸强度,而断裂伸长率有所提高,当HNT的质量分数为0. 4%时,断裂伸长率较纯PLA的提高了8. 86%。
Taking halloysite nanotubes (HNT)as the nucleating agent,poly (lactic acid)(PLA)/ HNT composites were prepared by melt-quench process using a twin-screw extruder.The morphology, crystallization behavior and mechanical properties of PLA/HNT composites were studied by scanning electron microscopy (SEM),X-ray diffraction (XRD),differential scanning calorimeter (DSC),polarizing microscope (POM)and tensile testing machine.The results of morphology indicate that the addition of HNT increases the roughness of the PLA section,and the fracture mode changes from source fracture to pore fracture.The analyses of crystallization behaviors suggest that the PLA/HNT composites prepared by the meltquench process have extremely low crystallinity,and the addition of HNT could not change the crystal form of PLA.Annealing could effectively improve the crystallization of PLA.The cooling rate has a great influence on the crystallization behavior of PLA.There is a significant difference between the 10℃/min and 2℃/min cooling process and the second heating process.The low cooling rate is more conducive to PLA crystallization. HNT could play the role of heterogeneous nucleation,reduce the nucleation barrier and increase the crystallinity of PLA.When the content of HNT is 1.2wt%,the crystallinity of the composite is 40.98% higher than the pure PLA,and the size of spherulites significantly decreases.The study on mechanical properties show that the addition of HNT could reduce the tensile strength of PLA and increase the elongation at break.When the content of HNT is 0.4wt%,the elongation at break of PLA/HNT composites is 8.86% higher than pure PLA.
作者
张显勇
王忠
贾仕奎
陈立贵
付蕾
ZHANG Xian-yong;WANG Zhong;JIA Shi-kui;CHEN Li-gui;FU Lei(School of Materials Science and Engineering,Shaanxi University of Technology,Hanzhong 723000,China)
出处
《塑料工业》
CAS
CSCD
北大核心
2018年第12期51-55,17,共6页
China Plastics Industry
基金
陕西省自然科学基础研究计划项目(2017JQ5071)
国家自然科学基金项目(51703121)
关键词
埃洛石纳米管
聚乳酸
断口形貌
结晶行为
力学性能
Polylactic Acid
Halloysite Nanotubes
Morphology
Crystallization Mechanical Properties Behavior
