The application of wood-plastic composites is growing rapidly in the fields of corrosion and aging. The present study investigated the effect of alkali-treated (with NaOH concentrations of 0.5, 2.5, 4.5, and 6.5%) sorghum straw (SS) fiber on the wear resistance of polyvinyl chloride (PVC) composites under simulated seawater and acid rain conditions. The results showed that the wear resistance of the SS/PVC composites was noticeably improved by the addition of the alkali-treated SS fiber. SS fiber treated with 4.5% NaOH showed low polarity and hydrophilicity with high crystallinity and improved mechanical properties, which endowed the SS/PVC composites with high interfacial bonding and wear resistance. Exposure to simulated seawater and acid rain resulted in the deterioration of physical (including water repellency and hardness), mechanical, thermal, and wear-resistance properties of the composites; the wear mechanism of the SS/PVC composites after corrosion for 12 days was mainly abrasive wear.

The application of rice husk fibers (RHFs) to reinforce wood plastic composites has received appreciable attention. However, good interfacial adhesion is important for actual applications. Pretreatment methods can reduce the hydroxyl groups in plant fibers in order for them to bond with the plastic matrix. In this research, RHFs were pretreated by four methods: hydrothermal treatment (HT), microwave treatment (MT), alkali treatment (AT), and benzoylation treatment (BT). The effects of the four pretreatment methods on aging behavior of RHFs/polyvinyl chloride (PVC) composites was studied with simulated soil-accelerated aging conditions. Accelerated-soil aging caused the physical and mechanical properties of the composites to deteriorate. The ultimate performance of the composites was improved by the pretreated RHFs. The effectiveness ranking of the pretreatment methods was: benzoylation-treated RHFs reinforced PVC (BRRP) > alkali-treated RHFs reinforced PVC (ARRP) > hydrothermal-treated RHFs reinforced PVC (HRRP) > microwave-treated RHFs reinforced PVC (MRRP) > untreated RHFs reinforced PVC (URRP).

With the widespread use of wood-plastic composites, they are inevitably affected by aging during transportation and outdoor use. In this research, in order to improve the aging resistance of WPC, acrylate-styrene-acrylonitrile (ASA) was used as modifier (10 parts, 15 parts, and 20 parts). The effects of the ASA modification on the aging behavior of eucalyptus/polyvinyl chloride (PVC) composites was studied with simulated xenon lamp artificial aging conditions. Artificial aging caused the physical and mechanical properties of the composites to deteriorate. After 960 h of aging, the aging resistance of the ASA-modified WPC was better than unmodified WPC and the sample with 15% ASA added had the best performance.

Wear Properties of Wood-plastic Composites Pretreated with a Stearic Acid-palmitic Acid Mixture before Exposure to Degradative Water Conditions

This paper reports an investigation into the effects of nano-silicon dioxide, nano-titanium dioxide and nano-aluminum oxide (nano-SiO₂, nano-TiO₂, and nano-Al₂O₃) on the water resistance and flexural properties of corn straw/polyvinyl chloride (PVC) composites under simulated soil accelerated aging conditions, and the reinforcing effect of three nano-fillers was compared. The results indicated that the addition of nano-fillers exhibited a positive effect on the water resistance and flexural resistance properties of corn straw/PVC composites, especially nano-SiO₂. After 21 d of the simulated soil accelerated aging, the nano-SiO₂ reinforced composites had relatively low water absorption and moisture absorption rates, and the similar enhancement effect was also found with flexural strength, flexural modulus and flexural creep resistance. The microstructure of nano-SiO₂ reinforced composites showed no significant breakage or pullout of the fiber, and the voids and the micro-cracks cannot be found in SEM observation indicating stronger interfacial bonding strength, thus improving the water-resistance and flexural resistance properties.