Weathering resistance of plant fiber‐reinforced high‐density polyethylene matrix composites: Effect of different pigments

Abstract The effects of iron oxide red pigment, organic red 254 pigment, titanium white pigment, and carbon black pigment on the properties of wood fiber (WF)reinforced high‐density polyethylene (HDPE) composites under outdoor aging conditions were investigated. The results indicate the addition of pigments in the outdoor aging process has a certain physical protection effect on the composites, effectively preventing the damage of ultraviolet rays on the WF/HDPE composites, and the mechanical experiments show that the pigments protect the composites more obviously in the first 3 months. Among them, the carbon black pigment had the best color‐fixing effect on the composites, with the ∆E* value is only 4.1, and the protective effect on the composites was relatively good due to its special structure. The quality change also verified again that the carbon black pigment has a certain protective effect on the plant fiber composites in the pre‐aging period outdoors, in which the mass of the composites with added carbon black pigment increased by 0.14%. Comprehensively, it shows that the addition of pigment cannot completely prevent the photo‐oxidation reaction of the composites from occurring, but it can effectively slow down the aging process of the composites and prolong the service life. Highlights WF/HDPE‐modified composites were prepared by injection molding. The surface color of composites with pigment additions was analyzed. The addition of pigments effectively protects the composites. Mechanical and thermal properties have also been investigated.