A variety of phosphorus - containing vinyl monomers, including phosphonic acids, phosphonates and phosphine oxides, have been copolymerized with both styrene and methyl methacrylate. The flame retardance of these copolymers has been explored in a preliminary way by measuring limiting oxygen index (LOI) and assessing thermal stability and char yields by thermogravimetric analysis (TGA). All of the copolymers are indicated to be more flame retardant than unmodified polystyrne and poly (methyl methacrylate), to greater or lesser extents, depending on the nature of the phosphorus - containing comoonomer. Flame retardance in these copolymers appears to involve both vapour - phase and condensed - phase mechanisms.
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