退火对PLA/GNPs/PEG复合材料性能的影响

利用自制的超声辅助真空装置制备石墨烯纳米片(GNPs)/聚乙二醇(PEG)复配成核剂,与聚乳酸(PLA)通过双螺杆挤出机熔融共混制备 PLA/GNPs/PEG 复合材料,并通过注塑机制成试样,采用扫描电子显微镜、广角 X射线衍射仪、差示扫描量热仪、偏光显微镜、万能力学试验机等测试和分析退火对复合材料结晶及力学性能的影响。结果表明,与未退火的 PLA/GNPs/PEG 复合材料相比,退火后复合材料的结晶度明显提高,当 GNPs/PEG 添加量为 0.1%,且在 110℃退火 1 h,其结晶度可达 37.31%;当 GNPs/PEG 的加入量为 0.3%并在 110℃退火 1 h,PLA/GNPs/PEG 复合材料的拉伸强度增加到 73.02 MPa,相比纯的未退火的 PLA,拉伸强度提高了 18.78%;与未退火PLA/GNPs/PEG 复合材料相比,退火后复合材料的冲击强度均有所下降。

Effects of Annealing on Properties of PLA/GNPs/PEG Composites

The grapheme nanoplates (GNPs)/polyethylene glycol (PEG) hybrid nucleating agent was prepared by ultrasonic assisted vacuum device,which generates dynamic impregnating force. Then,PLA/GNPs/PEG composites were prepared by twin-screw extruder via melting blending method. The standard samples for analyzing mechanical properties also were processed by injecting process. Scanning electron microscope,wide-angle X-ray diffraction,differential scanning calorimeter,polarizing microscope and universal mechanical testing machine were used to test and analyze the effects of annealing on crystallization and mechanical properties of PLA/GNPs/PEG composites. The results show that the crystallinity of the annealed PLA/GNPs/ PEG composite is significantly improved compared with that of the unannealed PLA/GNPs/PEG composite. When GNPs/PEG is 0.1%,the crystallinity of the annealed PLA/GNPs/PEG composite reaches 37.31%. Meanwhile,when the composite with the addition of 0.3% GNPs/PEG is annealed at 110 ℃ for 1 h,the tensile strength of PLA/GNPs/PEG composite increases to 73.02 MPa,which is 18.78% higher than that of pure PLA without annealing. Compared with the unannealed PLA/GNPs/PEG composites,the impact strength of all these composites slightly decreases after annealing.