紫外老化对PLA/TPU/TiO2复合材料结晶及力学性能的影响

Effect of UV-aging on Crystallization and Mechanical Properties of PLA/TPU/TiO2 Composites

以二氧化钛(TiO 2 )或热塑性聚氨酯(TPU)改性聚乳酸(PLA),利用双螺杆挤出机熔融共混制备一系列TPU/TiO 2 改性PLA复合材料,并在紫外线老化测试仪中进行老化试验。利用扫描电子显微镜(SEM)、广角X射线衍射仪(WAXD)、差示扫描量热仪(DSC)、偏光显微镜(POM)、万能试验机和悬臂梁冲击试验机对复合材料老化前后的断面形貌、结晶和力学性能进行了测试。结果表明:老化前,与纯PLA相比,PLA/TPU复合材料的结晶度和拉伸强度分别降低了50.1%、9.7%,冲击强度和断裂伸长率分别提高了83.6%、27.3%;PLA/TPU/TiO 2 复合材料的结晶度和拉伸强度分别降低了72.4%、0.83%,冲击强度和断裂伸长率分别提高了0.3%、8.9%;老化后,PLA/TPU/TiO 2 复合材料冲击断面老化前后变化最小,其结晶度、拉伸强度、断裂伸长率和冲击强度较老化后的纯PLA分别提高了35.1%、1.6%、13.6%、15.8%。

A series of different component ratios of titanium dioxide(TiO 2 )or thermoplastic polyurethane(TPU)were used to prepare modified poly(lactic acid)(PLA)by melt-blending using a twin-screw extruder.And aging tests were carried out in an ultraviolet aging test chamber.The fracture morphology,crystallization and mechanical properties of the composite before and after aging were tested by scanning electron microscope(SEM),X-ray diffraction(WAXD),differential scanning calorimetry(DSC),polarizing microscope(POM),universal testing machine and cantilever beam impact testing machine.The results show that before aging,comparing with pure PLA,the crystallinity and tensile strength of PLA/TPU composites decrease by 50.1%and 9.7%,the impact strength and elongation at break increase by 83.6%and 27.3%.The crystallinity and tensile strength of PLA/TPU/TiO 2 composites decrease by 72.4%and 0.83%,the impact strength and elongation at break increase by 0.3%and 8.9%.After aging,the fracture morphology of PLA/TPU/TiO 2 composites are the smallest changing before and after aging.comparing with the pure PLA after aging,the crystallinity,tensile strength,elongation at break and impact strength of the PLA/TPU/TiO 2 composites could increase by 35.1%,1.6%,13.6%,and 15.8%,respectively.