“All in One” Intumescent Flame Retardant Based on Alginates and Ammonium Polyphosphate for EVA Copolymer Resin: Toward Simultaneously Enhanced Flame Retardancy and Migration Resistance

ABSTRACT In recent years, ammonium polyphosphate (APP) based intumescent flame‐retardant systems (IFR) were widely used in ethylene‐vinyl acetate copolymer (EVA). However, APP‐based IFR have poor water and migration resistance. This paper introduced metal alginates to improve flame retardant efficiency and water resistance of IFR intramolecularly. The alginates IFR(IMA) with three sources and one synergistic agent were prepared by acid source and gas source (APP) and carbon source dipentaerythritol (DPER). IMA were APP/DPER assembled by sodium alginate, cobalt alginate and silane coupling agent. IMA significantly improved flame retardant, smoke suppression and migration resistance of EVA. Compared with 25%APP/DPER, the LOI values of 25%ICA increased obviously, UL 94 increased from no grade to V‐0, the peak of heat release rate value and total smoke produce value decreased by 36.1% and 16.8%, respectively. The reason was that the transition metal cobalt promotes the efficiency of carbonization and graphitization, and reduces the ratio of CO and aromatic compounds in the gas phase thermal decomposition products. None significant mechanical properties changed after adding the flame retardant The weight loss rate was significantly reduced by immersion in hot water at 70°C. The improvement of water resistance was related to the increase of water contact angle of ICA flame retardants.