Self‐extinguishing polystyrene foaming‐in‐place beads

摘要

AbstractThe preparation of practical self‐extinguishing polystyrene foaming‐in‐place compositions by suspension polymerization is described. The halogen necessary for self‐extinguishing characteristics is incorporated by chain transfer. The synergistic effect of organic peroxides decreases drastically the amount of halogen necessary. For example, 0.3 pph 1,2‐dibromotetrachloroethane in the presence of 0.2 pph dicumyl peroxide renders the composition self‐extinguishing, while 1.0 pph is necessary without peroxide. The rate of polymerization is unaffected by the presence of this chain transfer agent, while the molecular weight is reduced considerably. The effectiveness of other halogenated chain transfer agents and peroxy compounds has been demonstrated. Silicone mold release agent exerts a deleterious effect on the self‐extinguishi