Ultraviolet aging characteristics of waste laser printed paper reinforced high-density polyethylene (HDPE) based composite materials

To maximize the utilization of waste laser printed paper fiber (WLPF), WLPF was used as the organic reinforcing phase, high-density polyethylene (HDPE) was used as the matrix, vinyltrimethoxysilane (A171) and γ-methacryloxytrimethoxysilane (KH570) were used as coupling agents to modify and prepare WLPF/HDPE composites via a blending-injection molding process. The weather resistance properties and mechanisms of the composites were systematically analyzed using scanning electron microscopy, Fourier-transform infrared spectroscopy (FTIR), mechanical analysis, thermogravimetric analysis, and differential scanning calorimetry. The results showed that the KH570-modified WLPF/HDPE composites retained their excellent tensile and flexural strength after 2000 h of accelerated ultraviolet (UV) aging, and their tensile strength, flexural strength, and flexural modulus were 26.9, 41.0, and 2744.4 MPa, respectively. The thermal property analysis revealed that the thermal stability of the composites decreased after aging. Additionally, the crystallization enthalpy, melting enthalpy, and crystallinity of the composites increased. Highlights Waste laser printed paper fiber/high-density polyethylene (WLPF/HDPE) modified composites were prepared by injection molding process. Ultraviolet (UV) aging properties of WLPF/HDPE composites were investigated for the first time. KH570 modified composites retained excellent tensile and flexural strength after UV aging. The thermal properties of the composites after UV aging were also investigated.