Flame retardant compositions are disclosed which comprise (a) at least one
particulate material which expands on the application of heat and (b) at
least one particulate nano-filler, together with at least one polymer
and/or at least one curable monomer or oligomer. The compositions may
also contain certain silicon-based materials. Flame-retardant
compositions comprising polyorganosiloxanes containing one or more
functional groups selected form amino, hydroxyl, methacrylic, acrylic and
epoxy groups, are also disclosed.