Effects of silicone surfactant on the water absorption and surface morphology of rigid palm oil-based polyurethane foam

Abstract

Polyurethane (PU) foams are widely used today in automotive and as insulation system. Due to environmental issues, efforts have been made to replace petrochemical polyol with natural-based polyol in PU foam production, without sacrificing any properties. This study aims to produce palm oil-based PU rigid foam for non-load bearing applications such as wall panel or insulation for buildings. Two parameters studied were percentage of water uptake and surface foam morphology. Palm oil-based polyol (POP) was reacted with polymeric 4,4-diphenylmethane diisocyanate (p-MDI) at 1:1 NCO:OH ratio. Water was used as blowing agent and silicone surfactant was added to produce stable rigid PU foam. The content of silicone surfactant was varied at 2 and 3 part by weight (pbw). The percentage of water uptake increased slightly with increasing surfactant contents due to siloxane portion of the surfactants, is thought able to reduce the surface tension of the cell, thus absorbing more water than 2 pbw surfactant content. The findings were supported with micrographs of scanning electron microscope (SEM) that showed a larger cell window area and thicker strut.