Optimization of preparation process to produce polyurethane foam made by oilseed rape straw based polyol

Abstract

Oilseed rape straw based polyol was used as substitute of petroleum based polyol and to react with pMDI for preparing bio-based polyurethane (PU) foam. The optimal foaming process was confirmed as 1.7 of NCO/OH ratio, 4% of surfactant, 1% of blowing agent and 3% of catalyst. Effects of reactants formula on foaming process, density, mechanical property, thermal property and water absorption ability are investigated. Density, compression strength and elastic modulus increased firstly then decreased with increasing of NCO/OH ratio or surfactant, decreased with increasing of blowing agent, while decreased firstly and then increased with increasing of catalyst dosage. Tg increased with NCO/OH ratio, increased firstly and then decreased with surfactant, blowing and catalyst dosage. The optimal foam appeared 38.5 kg/m3 of density, 131.7 kPa of compression strength, 2.29 MPa of elastic modulus, uniform cellular structure with 150–250 μm of diameter cells, 10.2 MPa of storage modulus, 200.8 °C of Tg, excellent water absorption ability and thermal stability.