Sulfonate-Group-Containing Polymeric Polyamide for Simultaneous Transparency and Flame Retardancy of Polycarbonate

Inthe functionalization of transparent polycarbonate (PC), theaddition of additives often results in damage to the transparencyof polycarbonate, thereby limiting its application in the field witha high transparent requirement. In this study, sulfonate-group-containingpolymeric polyamide SK was synthesized and employed as a functionalagent for PC. The results demonstrated that the SK significantly improvedthe fire safety of PC. 1.0 wt % SK endowed PC with a UL-94 V-0 ratingand a limiting oxygen index of 30.4%; compared with that of neat PC,the maximum smoke density (Ds(max)) and the peak of heatrelease rate (PHRR) for 1.0 wt % SK-blended PC were decreased by 21%and 39%, respectively. More importantly, the transparency of the originalPC was maintained at 86.4% after incorporation of 1.0 wt % SK, showingonly a slight reduction. Here, excellent flame retardancy is ascribedto the synergistic effect of SK-caused physical cross-linking andcarbonization. While, high transparency is attributed to the amorphousnature of SK and its good compatibility with PC. This work demonstratesthat SK is an efficient polymeric functional agent for fabricatingtransparent and flame-retardant PC and provides another idea for designinga sulfonate-group-containing flame retardant differing from traditionalsulfonates for PC.