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

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.