Preparation of a novel agar/sodium alginate fire-retardancy film

A novel flame retardant film of agar/sodium alginate/boric acid (AG/SA/BA) was prepared in presence of various concentration of BA (2.5, 5, 10, 15 wt%) through solution casting method. The result showed that C-O-B bonds were formed between BA and matrix. The addition of BA enhanced the limiting oxygen index (LOI), which might be related to the interaction formed between BA and matrix and excessive BA existing in molecular skeleton. The thermal stability of crosslinking film containing BA concentration above 5 wt% was improved when compared to that of the film without BA. Overall, the addition of BA enhanced flame retardancy and thermal stability at appropriate BA concentration.