Simple preparation, big effect: Chitosan-based flame retardant towards simultaneous enhancement of flame retardancy, antibacterial, crystallization and mechanical properties of PLA.

Preparing biobased flame retardants in a simple and fast path, while simultaneously imparting exceptional overall properties to PLA, poses a significant challenge. This study successfully synthesized a novel modified chitosan-based flame retardant, CPPA, through a simple one-step method and applied it to PLA. With the addition of just 10 wt% CPPA, the PLA-10%CPPA achieved UL-94 V-0 classification, while the limiting oxygen index (LOI) value increased to 30.3 %. Additionally, the peak heat release rate (pHRR) decreased from 494 kW/m to 407 kW/m. The good compatibility between CPPA and PLA resulted in an 8.9 % improvement in the tensile performance of the PLA-CPPA composite. Furthermore, CPPA also enhanced the crystallization and antibacterial properties of PLA. This work provides a simple new approach for the development of multifunctional polymers.