Friction and wear properties of recycled natural fiber reinforced plant-derived polyamide 1010 biomass composites

To develop new engineering materials for sliding mechanical parts (referred to as tribomaterials in this paper) using only inedible plant-derived materials, this study aimed to investigate the frictional and wear properties of recycled natural fiber reinforced plant-derived polyamide 1010 (PA1010) biomass composites. Two types of recycled natural fibers: recycled jute fiber (R-JF) and recycled sisal fiber (R-SF) were used as the reinforcement fibers. PA1010 is made of sebacic acid and decamethylenediamine, which are obtained from plant-derived castor oil. In this study, R-JF and R- SF were surface-treated by two types of surface treatment: (a) alkali treatment by sodium hydroxide (NaOH) solution and surface treatment by ureidosilane coupling agent, and (b) alkali treatment by sodium chlorite (NaClO2) solution and surface treatment by ureidosilane coupling agent before addition to PA1010. These fiber reinforced PA1010 biomass composites were then extruded using a twin extruder and injection-molded. Their frictional and wear properties were evaluated by ring-on-plate type sliding wear test. Their worn surface, the transfer film on the counterface, and wear debris were observed with a scanning electron microscope to understand the wear mode. It was found that the frictional coefficient and specific wear rate of the biomass composites improved when added with R-JF and R-SF whose surface have been treated by alkali treatment and silane coupling agent. In particular, the combination of NaClO2 and ureido silane coupling agent was found to be the most effective surface treatment for improving the tribological properties of the biomass composites in constant load and velocity test. These results may be attributed to the change in the mode of wear mechanism according to the types of natural fiber used, surface treatment performed for realizing good dispersion of fibers in the composites, and good interaction adhesion between fiber and matrix polymer.