Flame-responsive aryl ether nitrile structure towards multiple fire hazards suppression of thermoplastic polyester.

Multiple fire hazards (heat, smoke, dripping) caused by thermoplastic polymers pose integrated risks. Halogen or phosphorus flame-retardants tend to increase toxic, smoke or dripping hazards due to their flame-retardant mechanism. The physical blending flame-retardants into matrixes also presents a migration dilemma with causing potential environmental threats. Herein, we propose a novel multi-hazards inhibition strategy by chemical-incorporating aryl ether nitrile structures into poly(ethylene terephthalate)(PET), which is a typical thermoplastic polymer and a major contributor of multiple fire hazards. Through flame-responsive cyclotrimerization and aliphatic fragment capture, the flammability risks and multi-hazards (heat, smoke, toxicity, dripping) are significantly suppressed. The limiting oxygen index of the modified PET increases from 21.0 to 31.0. The peak of heat release, total smoke release, and carbon monoxide production decrease by 49.0 %, 31.1 %, and 52.6 %, respectively. The dripping hazards are eliminated, and the UL-94 rating reaches to V-0 level with no dripping production. Hence, this state-of-art strategy supplies a new approach for the fire hazards suppression of thermoplastic polymers.