Effect of ultrasound-driven attapulgite loading on water-induced degradation behavior of rape straw/polyvinyl chloride composites and its mechanism

The water-induced deterioration of plant fiber reinforced polymer composites in humid environments seriously restricts their outdoor applications. Ultrasonic driving technology was innovatively introduced in this study to load nano-attapulgite (ATP) on the surface of rapeseed straw fibers to enhance the performance of rapeseed straw/polyvinyl chloride composites. The influence of ultrasound-driven ATP loading on the water-induced degradation behavior of the composites and its mechanism was explored combined with finite element numerical simulation. The results showed that the saturated water absorption of composites after ultrasound-driven ATP loading decreased from 11.09% to 10.11%, and the size expansion rate was significantly reduced. The hardness retention rate of the composites increased to 84.07%, and the retention rates of tensile strength, bending strength and impact strength reached 81.65%, 68.94% and 92.28% respectively after being degraded by water absorption for 3 months. Ultrasonic driving caused ATP uniformly loaded on the surface of straw fibers and effectively blocked moisture penetration, and fiber swelling and interface damage were suppressed. This study optimized the interface structure of the composite through ultrasound-driven ATP loading, systematically blocked the vicious cycle of water intrusion-interface damage-performance degradation, and provided a new strategy for the design and development of high-water-resistant biomass composites. This study provides a new strategy for the design and development of water-resistant biomass composites.