Preparation of a novel bio‐based ferric flame retardant for enhancing flame retardancy, mechanical properties, and heat resistance of polylactic acid

Abstract A fully bio‐based flame retardant PNF was prepared based on phytic acid, nicotinamide and iron salts in aqueous solution by a green and convenient ionic reaction, and then blended with polylactic acid (PLA) to improve its properties. The results demonstrated that the PLA composite containing 4 wt% PNF(PLA/4PNF) had a flame retardancy rating of UL 94 V‐0 and an oxygen index of 25.3%. In addition, the peak heat release rate (PHRR) and total heat release (THR) of PLA/4PNF were reduced by 27.0% and 27.7%, respectively, compared to pure PLA, and the flame retardancy index (FRI) was increased by 210%, demonstrating that PNF could effectively improve the flame retardancy of PLA. Moreover, the thermal conductivity of PLA/4PNF increased by 284% compared to pure PLA, making the material require higher heat to reach the combustion state. DSC and mechanical property tests showed that PLA/4PNF had 31.3% higher crystallinity, 5.2% higher heat deflection temperature and 10.0% higher flexural modulus compared to pure PLA, indicating that PNF effectively improved the mechanical properties and heat resistance of PLA. The research in this article broadens the application of bio‐based flame‐retardant PLA in the field of electronic appliances and office equipment.