四种预处理方法的稻壳/聚氯乙烯复合材料抗老化及热学行为

Anti-aging and thermal behavior of rice husk/polyvinyl chloride composites by four pretreatment methods

为探讨稻壳预处理(水热、微波、碱处理和苯甲酰化处理)对制备稻壳/聚氯乙烯(PVC)复合材料在模拟土壤老化条件下抗老化及热学行为的影响,采用综合热分析仪测试了稻壳/PVC复合材料的TG曲线,并测试了其线性热膨胀系数、力学性能和吸水性能,利用SEM观察其微观结构。结果表明:四种预处理均能提高稻壳/PVC复合材料抗老化及热学性能;处理后稻壳纤维表面更粗糙,纤维与基体界面结合更好,微裂隙较少。模拟土壤老化21天后,苯甲酰化处理稻壳/PVC复合材料初始热分解温度比未处理稻壳/PVC复合材料提高了3.9%,其线性热膨胀系数下降了6.72%。24h吸水率降低了55.6%,拉伸强度和硬度分别提高了103%和119%。苯甲酰化处理稻壳/PVC复合材料中稻壳分布均匀,界面结合较好。四种预处理方法优劣顺序为:苯甲酰化处理>碱处理>水热处理>微波处理。

In order to investigate the effect of rice husk fiber pretreatment method(hydrothermal,microwave,alkali treatment and benzoylation treatment)on the thermal and anti-aging behavior of rice husk fiber/polyvinyl chloride(PVC)composites in simulated soil aging conditions,the TG curves of rice husk fiber/PVC composites were performed by a comprehensive thermal analyzer.The linear thermal expansion coefficient,mechanical and water absorption properties of rice husk fiber/PVC composites were characterized and the microstructure was observed by SEM.The results indicate that all the four treatment methods can improve the thermal behavior and anti-aging properties of rice husk fiber/PVC composites.The surface of the treated rice husk fiber is rougher,and the better interface of fiber and matrix lead to reducing micro-cracks.After 21 days simulated soil aging,the thermal initial decomposition temperature of benzoylated rice husk/PVC composites increases by 3.9%,compared with the untreated rice husk fiber/PVC composites.The linear thermal expansion coefficient and 24 hwater absorption of benzoylated rice husk fiber/PVC composites decrease by 6.72% and 55.6%,respectively.The tensile strength and hardness increase by 103% and 119%,respectively.The benzoylated rice husk fiber/PVC composites have a good interface,and the rice husk fiber distribute uniformly.So the sequence of the four pretreatment methods is:benzoylation treatment>alkali treatment>hydrothermal treatment>microwave treatment.