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

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 h water 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.