A cone calorimetric study of flame retardant elastomeric polyurethanes modified with siloxanes and commercial flame retardant additives

Polyurethanes are the single most versatile family of polymers with a wide range of applications. There is a substantial need for the development of p olyurethane materials with low heat release rate and low smoke release rate . In this study, an extensive series of elastomeric polyurethanes based on diphenylmethane-4,4 '-diisocyanate (MDI) prepolymers were prepared and furt her modified with fluid and powered siloxanes and conventional flame retard ant additives. The flame retardant behavior of these polymers was studied u sing the Cone Calorimeter (ASTM: E-1354), the instrument that has emerged a s an important tool for the analytical testing of materials for their fire properties.** All powdered siloxane additives used in this study, even at 5 % loading level, gave a 70-80% reduction in peak heat release rates compare d to standard materials. The reductions of peak HRR of fluid siloxane-modif ied materials compared to the base material were in the range of 49-78%. Th e conventional flame retardant additives used in this study also reduced pe ak heat release rate dramatically. The synergistic effect of conventional f lame retardant additives with siloxane powders is discussed.