Processing and properties of palm oil-based rigid polyurethane foam

Abstract

Rigid polyurethane (PU) foam has been prepared from palm oil-derived polyol. The polyol was synthesized by transesterification reaction of palm oil and pentaerythritol using calcium oxide as a catalyst. The obtained palm oil-based polyol was reacted with commercial polymeric diphenylmethane diisocyanate in the presence of water (blowing agent), N,N-dimethylcyclohexylamine (catalyst) and polydimethylsiloxane (surfactant) to produce rigid PU foam. The effects of the amount of the catalyst and surfactant on foam properties (i.e. density, compressive strength and thermal behaviors) were studied. It was found that the density of the foams decreased whereas the compressive strength increased with the increasing amount of catalyst and that they were in the range of 38.7-59.0 kg/m3 and 193.6-268.4 kPa, respectively, while an increased amount of surfactant showed negligible effect on these two properties. Furthermore, TGA revealed that the degradation temperature of the prepared foams was about 377°C. Moreover, scanning electron micrographs showed that the cells of the obtained PU foams were closed cells. In addition, the foams were found to have higher number of cells as the concentration of catalyst increased, while the uniformity of cells increased with increasing amount of surfactant.