Comparative study on properties of different fibers (unmodified/modified) reinforced polylactic acid degradable composites under ultraviolet aging conditions

Abstract Laser printing waste paper fibers (LPWF) are classified as high‐quality secondary fibers, characterized by their lightweight nature, high modulus of elasticity, and excellent fiber quality. These attributes present significant opportunities for their application in plant fiber/resin matrix composites. However, the deinking process for LPWF is more challenging compared to traditional waste paper. The conventional recycled paper manufacturing sector often operates with lower value‐added processes, highlighting the urgent need for the industry to achieve high‐value utilization of laser printing waste paper. In this study, we utilized environmentally friendly and abundant sources of LPWF, alongside the biodegradable resin polylactic acid (PLA), as raw materials. LPWF/PLA composites were prepared through melt blending and injection molding techniques, and their performance was compared to other composites made from natural plant fibers (such as wood and straw) in ultraviolet‐accelerated aging experiments. The results demonstrated that the LPWF/PLA composites exhibited superior overall performance after ultraviolet exposure. To enhance the ultraviolet aging resistance of the LPWF/PLA composites, we modified them with dodecenyl succinic anhydride (DDSA) and the ultraviolet absorber UV‐531 combined with silicon dioxide (SiO 2 ). Our findings indicated that the incorporation of these modifiers effectively protected the surface color of the composites, mitigated the degradation of mechanical properties and overall quality, and significantly reduced the occurrence of surface cracks. Notably, the modification using UV‐531/SiO 2 yielded the most pronounced protective effects. Highlights Comparison of the properties of three composites before and after UV aging. LPWF have a low lignin content and exhibit outstanding resistance to UV aging. Exploring the ultraviolet aging mechanism of plant fiber/resin composites. Two modifiers were used to modify LPWF/PLA composites. Providing new insights for extending the life of plant fiber‐resin composites.