A Novel Starch‐Based Synergistic Flame Retardant for the Treatment of Insulating Paper

Abstract Due to the strict working environment, insulating paper is generally required to have a good flame retardant performance. In this study, a new type of starch‐based synergistic flame retardant (SPBD) is prepared using starch as a carbon source, phytic acid, and boric acid as the acid source, and dicyandiamide as a gas source by the one‐pot method. The flammability, mechanical, and electrical properties of the flame‐retardant insulating papers treated with SPBD are also studied. When the concentration of the SPBD is 24.0%, the limiting oxygen index of the insulating paper is increased from 19.4% to 44.0% and reaches the level of UL‐94 V0. The tensile index and burst index of the flame‐retardant insulating papers are only 6.88% and 10.75% lower than that of the control insulating paper. While the ring crush strength and alternating current (AC) breakdown strength in air are 109.58% and 21.15% higher than the control insulating paper. The SPBD flame retardant has a good application prospect in insulating paper.