New ceramifying polymer materials for passive fire protection applications

A new class of polymer composites has been developed for flame retardancy and passive fire protection. The key feature is a controlled transition from a degrading polymer composite to a ceramic residue In a fire situation. The polymer can be thermoplastic, thermoset or elastomeric. The composites are processable using conventional equipment to form extruded profiles, sheet, moldings, each of which may be foamed. The composites can retain flexibility and durability within the required filler content range. Fire protection Is afforded by formation of a ceramic by fusion and reaction of the fillers over a defined temperature range. Ceramic formation commences at relatively low temperature coincident with polymer pyrolysis to maintain structural integrity of the material and minimizes shrinkage. The ceramic is able to develop adequate strength to maintain a fire barrier. One form of the material has been implemented in fire resistant cable sheathing. The composites discussed were prepared from poly(siloxiane) elastomer to demonstrate the concept.