The Application of a Novel Char Source From Petroleum Refining Waste in Flame Retardant Thermoplastic Polyurethane

Carbon 9 (C9) resin is a major by-product of the petrochemical industry and is rich in unsaturated hydrocarbons. By copolymerization with maleic anhydride (MAH), the product MAH-C9 was used as a carbon foaming agent. Combining MAH-C9 with ammonium polyphosphate (APP), which served as an acid and a gas source, an intumescent flame-retardant system was introduced into thermoplastic polyurethane (TPU). Flammability evaluation indicated that 4.5 wt% APP and 0.5 wt% MAH-C9 helped TPU achieve the maximal limiting oxygen index value of 25.9%, passing UL-94 V-0 rating. Total smoke release was decreased from 1,884.4 m(2)/m(2) for neat TPU to 833.0 m(2)/m(2) and char formation was promoted. The mechanical loss brought by 5 wt% APP was a little recovered by 4.5 wt% APP/0.5 wt% MAH-C9. POLYM. ENG. SCI., 2020. (c) 2020 Society of Plastics Engineers