Effects of organic and inorganic pigments on steam-aging resistance of bamboo fiber/high-density polyethylene composites: an experimental study

Abstract

The high sensitivity and low tolerance of lignocellulosic fiber-reinforced polymer composites (LFPC) to water-rich conditions diminish their aesthetics and durability. In this study, organic and inorganic pigments were compounded with bamboo fiber (BF) and high-density polyethylene (HDPE) into LFPC materials. The pigment-colored BF/HDPE composites were used to investigate the physical, chemical, mechanical, and wear properties after steam-aging for different durations. The results showed that pigment-colored BF/HDPE composites exhibited superior steam-aging resistance compared to control BF/HDPE composites, including less total discoloration (excluding light pigment-colored BF/HDPE composites) and oxygen exposure, higher mechanical properties and wear resistance, better water resistance and BF filler/HDPE matrix interface, and lower surface roughness in the same aging conditions. There was no chemical interaction between the pigments and either the BF filler or the HDPE matrix. Steam-aging had a limited degradation effect on the molecular chain stability of the HDPE matrix. As a result of erosive wear, increased surface roughness, pulverization of the BF filler, and ductile fracture of the HDPE matrix were observed on the erosive surfaces of the control and pigment-colored BF/HDPE composites.