Effects of pretreatment on the soil aging behavior of rice husk fibers/polyvinyl chloride composites

Abstract

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).

Effects of rice husk fibers on the properties of mixed-particle-size fiber-reinforced polyvinyl chloride composites under soil accelerated aging conditions

“…In addition, the simulated soil (high temperature and moisture) acted as a plasticizer for the cellulose networks of the plant fibers, resulting in more free movement of cellulose molecules and decreased deformation resistance of the cellulose structures. 17 Superior interfacial adhesion improves energy absorbing ability and the best explanation for the energy absorption in this case is the optimal length and distribution of fibers. 27,28 Optimally distributed fibers can lead to tight bonding between the fibers and matrix.…”

“…In addition, composites are often in direct contact with soil, meaning long soil aging can lead to the degradation of mechanical and thermal properties. 11,16,17 Various experts have researched the natural soil aging resistance of WPCs. The results have revealed the degradation of mechanical properties, color lightening, weight loss, and weak interfacial adhesion.…”

“…For composites in environments with high temperature and moisture, the mass variation process of the fibers (disappearance of hemicellulose and lignin) is similar to hydrothermal and acid treatment. 17 However, the addition of mixed-particle-size fibers resulted in stronger interfacial adhesion and fewer micro-cracks (Figure 3(c)), allowing heat to transfer from the matrix to the fibers. Therefore, it can be concluded that the addition of mixed-particle-size fibers is helpful for improving the thermal resistance of composites.…”

Development of Compatibilized Polyamide 1010/Coconut Fibers Composites by Reactive Extrusion with Modified Linseed Oil and Multi-functional Petroleum Derived Compatibilizers

“…Typical polymer matrices in WPC include commodity polymers such as low-and high-density polyethylene (LDPE and HDPE) [20,21], polypropylene (PP) [22,23], polystyrene (PS) [24], polyvinyl chloride (PVC) [25] and some polyamides (PA) [26,27].…”

Effects of desilication pretreatment on rice husk/high‐density polyethylene bio‐composites

“…The RH pretreated by acid and thermochemical pretreatments is always seriously damaged; therefore, it loses considerable strength, making it unsuitable to prepare a polymer composite. [19,20] Alkali pretreatment could destroy the connection between cellulose and hemicellulose under boiling conditions, and saponify the ester bond between hemicellulose and lignin. Also, alkaline conditions will cleave the C O C linkage of lignin, which assists in depolymerization and disruption of lignin for improved access to cellulose and better reactivity.…”