Toward flame retardants or thermal stabilizers with new mechanism for polymers

Abstract

This review discusses conventional flame retardants for polymers and the possibility of using endothermal materials as flame retardants. Halogen-based, phosphorus-based, inorganic compounds, and their combinations are generally used as flame retardants for polymeric materials. The mechanism of action involves the trapping of radicals in the gas phase, an endothermic dehydration reaction, the blocking of oxygen, and a heat insulation effect by char in the solid phase. We discuss the possibility of using low-molecular-weight organic (or inorganic) metal complexes, exhibiting unique endothermic phenomena, such as phase transitions and cold crystallization, as flame retardants or thermal stabilizers at lower temperatures. In addition, this review provides an outlook on state-of-the-art) polymer flame-retardant technology.