Cross-linked structures reinforced the bamboo fiber/poly(lactic acid) composites with high heat resistance and their environmental impact through the life cycle assessment analysis

In order to prepare low-cost and heat-resistant poly(lactic acid) (PLA) composites, in this study, bamboo fiber (BF) was added to stereo-complex crystal PLA (SC-PLA) to prepare heat-resistant composites. Poly[(phenyl isocyanate)- co -formaldehyde] [a polyaryl polymethylene isocyanate (PAPI)] was used to form cross-linked structures between SC-PLA and BF, and the effects of PAPI-cross-linked structures on the crystallization properties, mechanical properties, and heat resistance of BF/SC-PLA composites with different BF contents were systematically investigated. When 15% BF was added, the mechanical properties of the composite were significantly improved. The tensile strength increased by 85.5% compared to the unmodified composite, reaching 34.7 MPa, which was even higher than that of the SC-PLA composite (33.1 MPa). In addition, in order to explore the impact of the PAPI-modified BF/SC-PLA composite on the environment and carbon emissions, a life cycle assessment (LCA) of the composites was conducted. The addition of BF effectively reduced the impact of the composite on the environment. Notably, the emissions of CO 2 decreased by approximately 11.7%, and the freshwater, marine, and land ecotoxicity were also significantly reduced. This work provided a reference for the preparation of low-cost and heat-resistant PLA composites for heat-resistant food packaging and disposable tableware and expanded the application of PLA products in the field of heat-resistant materials.