The flammability of cis-1,4-polybutadiene vulcanizates

The flammability of dicumyl peroxide-crosslinked cis-1,4-polybutadiene vulcanizates was studied in relation to flame retardants like antimony trioxide, chloroparaffins, antimony trioxide-chloroparaffin blends, hexabromobenzene, melamine cyanurate, aluminum hydroxide and poly(ammonium-melaminc phosphate) used as additives. The oxygen index (OI) and the thermovision methods (Table 1) were used to test the flammability of vulcanizates. The enthalpy of combustion of the vulcanizates was determined in a calorimetric bomb. In terms of the OI data (Table 2), hexabromobenzene and aluminum hydroxide are seen to be most effective flame retardants. With aluminum hydroxide (100 phr) the vulcanizates went out immediately after the source of fire was removed. No correlation was found to exist between the OI and the enthaply of combustion (Table 4). Except for chloroparaffins, the flame retardants caused a considerable drop of the maximum flame temperature of the vulcanizates (Table 3).