Fire retardant fillers for polymers

The application of many polymers is limited by their inherent flammability. Various routes are available to overcome this drawback through the inclusion of additives to inhibit ignition. These function by different mechanisms, tend to be polymer specific and may contribute to or suppress the smoke produced during burning, depending on their mode of action. There has been a trend in recent years, driven principally by environmental and safety considerations, towards use of halogen free fire retardant systems, including intumescent formulations and dehydrated fillers. These have been widely applied commercially, with improved systems under active development. This review will consider fire retardant fillers, their characterisation, application to different polymer types, current understanding of their mechanism of action as fire retardants and smoke suppressants, and means for improving their efficiency. This includes combination with other fire retardants as synergists, in addition to broader implications determining their successful application, in particular their influence on the rheology of polymer melts and thermoset resins and their effect on the mechanical properties of host polymers.