Simultaneous enhancement in mechanical properties and flame retardancy of reed charcoal/polypropylene composites by graphene oxide interfacial modification

Biochar/polypropylene composites (BPCs) have great potential in automobiles and building materials due to their ease of processing and light weight. However, the inferior interfacial bonding strength between biochar and polypropylene (PP) and flammability of PP often result in the weak mechanical properties and poor flame retardancy of BPCs, which limit the practical applications of BPCs. Herein, graphene oxide (GO) is used as an active interfacial modifier to prepare graphene-reed charcoal/polypropylene (G-RC/PP) composites. Benefiting from the mechanical interlocking effect formed by GO, the G-RC/PP composites exhibit higher tensile and flexural strengths. When 1 % of GO was added (relative to mass of RC), the tensile and flexural strengths were 22.84 MPa and 50.8 MPa, respectively, which are 16 % and 22.7 % higher than pure PP. Additionally, the barrier-adsorption-dilution synergetic effects of GO enhance both the thermal stability and flame retardance of the composites. The total heat release rate of G-RC/PP composites is reduced by 71.6 % compared to RC/PP when GO was added at 1 %, resulting in a substantial reduction in fire hazards. This study offers a fresh perspective on the development of biochar/plastic composites with exceptional mechanical properties and high fire safety towards extensive applications as automotive parts and building structures.