Physical Properties of Soy-polyol Based Polyurethane Foams Reinforced with Microspheres and Nanoclay

Abstract

This study investigated the effect of incorporating microsphere and nanoclay fillers from 1-7% on the physical properties of polyurethane (PU) foams made from a polyol containing 15% soybean oil based polyol. With increasing filler percentage, the PU foam volume increased because these fillers provided surfaces for nucleation and more gas bubbles were generated during the foaming process. The compressive strength of PU foams decreased slightly when increasing the microsphere content from 1 to 3% and then increased when the filler was higher than 3% . At 7% microsphere content, the foams displayed the same compressive strength as the control foams made from 100% petroleum polyol. For PU foams reinforced with nanoclay, their compressive strength changed little from 1 to 5%, but decreased at 7% due to a lower density. Foams containing 5 to 7% microspheres or 3 to 7% nanoclay had density-compressive strength comparable or superior to the control. SEM was used to observe the morphology of reinforced foams. Foams reinforced with fillers had more cells and smaller cell size than foams made from 15% soy-polyol but without fillers. During the foaming process, the maximal temperatures reached by PU foams containing were not affected by the presence of 1 to 7% of microspheres or nanoclay, but slightly lower than the control. In addition, foams with fillers displayed roughly the same thermal conductivity as soy-polyol based foams without fillers.