Modification of PLA fibers with novel chitosan-based flame retardants by centrifugal melt electrospinning

Abstract

A novel flame retardant (CSFR) was developed by grafting polylactic acid (PLA) and melamine phosphate ester onto a chitosan framework to enhance the flame retardancy of PLA fibers without compromising their other excellent properties. The PLA/CSFR flame retardant fiber membranes were successfully prepared using a self-designed constant temperature centrifugal melt electrospinning device. Results demonstrated that the synthesized CSFR exhibited a mass residue of 30% at 800°C. Adding a small amount of CSFR effectively improved the fibers' flame retardancy and mechanical properties, while excessive CSFR content resulted in a decline in mechanical performance. The optimal content of CSFR was determined to be 1.0%. The PLA/1.0%CSFR fibers achieved an impressive oxygen index of 42.3% and a mass residue of 7.98% at 800°C. Furthermore, the modified fibers significantly enhanced maximum elongation by 137.5% and tensile strength by 130.27% compared to pure PLA fibers. The molecular weight of the modified fibers decreased by 66.15%, and the mass loss rate was 8.57% after 12 hours of UV irradiation. The synthesized PLA/1.0%CSFR fibers exhibited exceptional flame retardancy, thermal stability, mechanical properties, and UV degradation performance.