Abstract
This paper extends previously reported work and describes the influence that a range of selected flame retardants have on the burning behaviour and pyrolyses of homo-and copolymers of acrylonitrile. Various inorganic and organic phosphorus and nitrogen- or sulphur-containing, halogen-containing (in the absence and presence of halogen or antimony (III) oxide) and nitrogen-containing flame retardants and red phosphorus were studied using LOI, TGA, DSC and residual char measuring techniques. Flame retardancy relates directly to char-forming tendency for all retardants and their ability to reduce the dominance of flammable volatiles formed during the first stage of acrylic polymer pyrolysis. Ammonium phosphates are particularly effective flame retardants for the selected copolymers. Possible mechanisms of retardant activity are discussed, including the char-forming tendency of antimony–bromine combinations.