竹纤维增强聚乳酸复合材料热老化性能

采用氢氧化钠和异氰酸酯处理的界面调控方法对竹纤维(BF)增强聚乳酸(PLA)复合材料界面进行调控,通过注射成型工艺制备BF/PLA复合材料。利用FTIR、XRD、凝胶渗透色谱及SEM等分析手段研究了BF/PLA复合材料热老化性能。研究发现: 热老化过程中PLA分子链中的C O不断水解,分子链的C—O断裂生成聚合度更低的小分子量的PLA,PLA结晶度减小,PLA与BF的接合界面被破坏,拉伸强度和冲击强度随老化时间的增加逐渐降低。BF/PLA复合材料在80℃热老化16天后拉伸强度和冲击强度分别降低了75%和77.6%,在100℃热老化32 h后拉伸强度和冲击强度分别降低了80.3%和83.4%。温度对BF/PLA复合材料老化影响显著,温度越高,老化速度越快。

Thermal aging properties of bamboo fibers reinforced polylactic acid composites

The interface of bamboo fibers(BF) reinforced polylactic acid(PLA) composites was regulated by hydroxide and isocyanate, and BF/PLA composites were prepared by injection molding process. The thermal aging properties of BF/PLA composites were studied by the methods of FTIR, XRD, gel permeation chromatography (GPC) and SEM. The results show that the C O in the molecular chains of PLA are continuously hydrolyzed, the C—O in the molecular chains of PLA are fractured and generated the PLA of smaller molecular weight and lower polymerization degree, the crystallinity degree of PLA is reduced, the bonding interface between BF and PLA is destroyed, the tensile strength and impact strength gradually decrease with the increasing of aging time in the thermal aging process. The tensile strength and impact strength of the BF/PLA composites reduce by 75% and 77.6% after thermal aging at 80℃ for 16 days, while the tensile strength and impact strength of the BF/PLA composites reduce by 80.3% and 83.4% after thermal aging at 100℃ for 32 h. The effect made by temperature on the aging property of BF/PLA composites is significant, the higher the temperature, the faster the aging.