A novel sustainable strategy of upcycled waste polyphenylene sulfide filter bag: From waste polyphenylene sulfide powder to char‐forming agent for flame retardant epoxy

Abstract Polyphenylene sulfide (PPS) filter bag is widely used in the field of high temperature filtration of coal dust because of its high temperature resistance and stable chemical properties. However, as nondegradable solid waste, incineration is main solution for waste PPS filter materials which also brings harm to the environment. To achieve green recycling and efficient utilization of waste PPS filter material, waste PPS is utilized as the charring agent together with ammonium polyphosphate (APP) to form a compound flame retardant to improve flame retardancy of epoxy resin (EP). Due to the excellent char‐forming ability of PPS, good performance of EP/APP/PPS composites is obtained in the rigorous combustion test. When the mass ratio of APP and waste PPS is 3:1 and the total load is 15 wt%, EP/IFR3 composite can pass the UL‐94 V‐0 rating, and its LOI increase to 28.1%. Furthermore, cone calorimetry tests presented its peak heat and smoke release rates were reduced by 49.9% and 63.6% compared with neat EP, respectively. Residual carbon analysis shows that this system is mainly a condense‐phase flame‐retardant mechanism. In addition, due to poor dispersion and compatibility, the flexural performance and thermal stability are destroyed to a certain extent.