THE EFFECT OF HEAT SINK ADDITIVES ON THE IGNITION AND HEAT RELEASE PROPERTIES OF THERMALLY THIN THERMOPLASTICS

The retardancy effect of additives, undergoing an endothermic decompos ition in the solid phase, upon flammability properties of thermally th in thermoplastics is investigated. The criterion for ignition is that of a critical mass flux of volatiles pyrolysed from the solid into the gas phase. Strong coupling between the solid and gas phases is thus n eglected in this model. The kinetic parameter values are set up in suc h a way that easy comparison can be made between the cone calorimeter and thermogravimetric analysis (TGA). The requirements for an additive to have maximal effect on ignition time and maximal mass loss rate ar e found to contrast, so that a simple heat-sink additive cannot maximi se both. (C) 1997 Elsevier Science Ltd.