Characterization of Rice Husk Fiber-Reinforced Polyvinyl Chloride Composites under Accelerated Simulated Soil Conditions

Abstract

To study the effect of accelerated simulated soil aging on the physical, mechanical, and thermal behavior of rice husk fiber-reinforced polyvinyl chloride composites. The worst soil aging condition was determined using the orthogonal design method, and the physical, mechanical, and thermal properties of the composites were analyzed over 21 d. The results indicate that the worst soil-accelerated aging condition was as follows: soil temperature of 65°C, soil pH of 2.5, soil moisture content of 45%, and soil porosity (ratio of thick to thin) of 3 : 7. An extended aging time tends to cause poor interfacial bonding quality, and the presence of many microcracks reduced thermal stability and flexural and impact strength. Many fibers were exposed, which resulted in increasing 24 h water absorption and thermal expansion coefficient. The hardness, tensile strength, flexural strength, impact strength, and pyrolysis temperature of the composites (after 21 d of aging) decreased from 50 HRR, 17.42 MPa, 35.2 MPa, 3.19 kJ/m2, and 258.5°C to 26 HRR, 11.5 MPa, 16.8 MPa, 1.16 kJ/m2, and 251.3°C, respectively. The mass loss rate, 24 h water absorption, discoloration, and line thermal expansion coefficient of the composites increased from 0%, 4.19%, 0, and 28.43 to 2.9%, 7.92%, 29.03, and 29.98, respectively.