木塑复合材料的老化性能

Aging Properties of Wood-Plastic Composites

为探讨贵州省特殊气候环境下木塑复合材料(WPCs)的老化性能,采用两步挤出成型法制备了马尾松/高密度聚乙烯(HDPE)复合材料和杉木/HDPE复合材料,研究室内、户外自然老化对其力学性能的影响,分析动态热机械性能,并利用数学模型模拟WPCs老化后的力学性能保留率。结果表明,室内自然老化对WPCs的韧性影响很大。户外温度较低,湿度较高,温差、水分和光照的协同作用加速了WPCs弯曲、拉伸和冲击性能的损耗。杉木/HDPE复合材料的力学性能较好且抗老化性能较优,适合应用于户外,但不宜用于制作承担拉力作用的构件。二阶多项式模型适合模拟WPCs的力学性能随老化时间的变化趋势,线性回归模型适合预测WPCs在使用若干时间后的力学性能保留率及使用寿命。

In order to investigate the aging resistance of wood-plastic composites(WPCs)in the special climatic environment in Guizhou province,Pinus massoniana and Cunninghamia lanceolate flour were used to reinforce high density polyethylene(HDPE)by the two-step extrusion molding method.The effect of indoor and outdoor natural aging on the mechanical properties of P.massoniana/HDPE composites and C.lanceolate/HDPE composites was investigated.Dynamic mechanical properties of the composites were analyzed.Retention rate of mechanical properties after aging was simulated using mathematic models.The results show that the toughness of WPCs is greatly affected by natural indoor aging.Outdoor temperature is lower,and humidity is higher.The loss of flexural,tensile and impact properties of WPCs is accelerated due to the synergistic effect of temperature,moisture and light.C.lanceolate/HDPE composites are suitable for outdoor applications because of their better mechanical properties and anti-aging properties,but not suitable for making components that bear tensile load.The Quadratic Polynomial model is suitable for simulating the change trend of the mechanical properties of WPCs with aging time,and the Linear Regression model for predicting the service life of WPCs and retention rate of mechanical properties after a certain period of service.