Synthesis of novel biobased polyol via thiol-ene chemistry for rigid polyurethane foams

Abstract

The objective of this research is to prepare rigid polyurethane (PU) foams from α-phellandrene, a biobased compound. Two types of polyols were synthesized by reacting α-phellandrene with 2-mercaptoethanol and α-thioglycerol via thiol-ene chemistry route. The completion of the reaction was identified by using FTIR. PU foams from α-phellandrene polyols and commercial polyol were compared with regard to foam characteristics and properties. All the PU foams showed apparent density of 28–39 kg/m3 with closed-cell content above 90%. The highest glass transition temperature of 229 °C and compressive strength of 220 kPa were observed for the polyol synthesized by reacting α-phellandrene and α-thioglycerol, due to the higher number of hydroxyl functionalities. The type of polyol also had an influence on thermal stability and foam reactivity. The PU foams from α-phellandrene polyol had lower onset degradation temperature. However, this was improved upon blending with commercial polyol. Foam reactivity was the highest in the polyol consisting of primary hydroxyl groups. This study establishes the preparation of biobased polyols from α-phellandrene for the preparation of rigid PU foam which could be suitable for thermal insulation.