Abstract

Semi-rigid polyurethane foams (SPUF) with high deformation resistance and strength are indispensable for cushioning applications. However, for high fire risk and cascaded pollutant effects, overused multifarious additives and foam wastes exacerbate global environmental concerns. One option to address this issue is to develop eco-friendly multifunctional flame retardants that participate in the material lifecycles of preparation, safe service, waste management, and sustainable recycling. Herein, a novel self-adaptive catalytic strategy is reported that exploits the temperature and agent structure-responsive catalytic ability of eco-friendly sodium propionate (SP), reconciling the often-conflicting properties of fabrication and recycling while effectively mitigating combustion risks and additive pollution. The adaptive catalytic function of SP impressively involves all aspects of foam life cycles: 1) catalyzing foaming without complex/hazardous catalysts; 2) providing superior flame-retardant efficiency with a high limiting oxygen index of 25.5% without relying on traditional flame retardants; 3) promoting in situ network fragmentation and reorganization into strong adhesives (5.8 MPa); and 4) further recycling of the newly formed adhesives in a self-driven sustainable manner. A novel green strategy is presented that addresses fire hazards, plastic pollution, and the unsustainability of recycling, minimizing the ecological risks of foam, which will positively impact future sustainable material design involving diverse additives.