Effects of Silane Coupling Agent on the Thermal Conductivity and Exfoliation of Organoclay Layers in Polyurethane/Organoclay Nanocomposites Foams

摘要

An attempt was made to synthesize polyurethane (PU)/organoclay nanocomposites foams having high thermal insulation property. The organoclay was modified by the polymeric 4,4'diphenylmethane diisocyanate (PMDI) with silane coupling agent. It is expected that the distance between organoclay layers would be increased and the organoclay is dispersed in nano scale in PU matrix due to the organic/inorganic hybrid bond formation between organoclay and silane coupling agent. The thermal conductivity was appreciably decreased from 0.0217 to 0.0198 kcal/mh °C in the PU/silane coupling/organoclay nanocomposites foams. From results of morphological and thermal properties, it is suggested that the smaller cell size and lower thermal conductivity of the PU/organoclay nanocomposites foams are mainly due to enhanced exfoliation of the organoclay layers by silane coupling reaction.