Enhanced flame retardant performance of poly(vinyl alcohol) composites based on phosphorus–metal ion synergistic effect

Abstract

Natural polysaccharides with intrinsic flame retardant, biodegradable, and environment-friendly capability have received considerable attention. Sodium alginate (SA) is considered a promising synergist for improving fire retardance. Herein, flame retardant poly(vinyl alcohol) (FR-PVA) composites containing ammonium polyphosphate (APP) and SA are produced by a facile blending method with a lower loading of 15%, which exhibit an ideal limited oxygen index (30.2%), UL-94 V-0 rating, high heat release reduction (42.7%), and self-extinguishing properties. SA not only retards the agglomeration of APP with negatively charged groups, but also enhances flame retardance by catalyzing the formation of char carbon. Hydrogen bonding between PVA and SA induced a physical cross-linked network inhibiting the movement of PVA molecules, thereby affording anti-dripping properties and mechanical strength. This study provides a new scenario of FR-PVA composites with high transparence, environmental friendliness, and fire safety applicable in packaging, home textiles, and biomaterials.