The Energy-Efficient and Environmentally-Friendly Vetiver-Polyurethane Thermal Insulation Foams

This experimental research investigates the thermal conductivity and mechanical properties of the rigid thermal insulation foams fabricated from mixtures of vetiver fibers (VF) and the polyurethane (PU) composites. The vetiver fibers were of three mesh sizes (100, 150 and 200 mesh) and the VF concentrations were varied from 0%, 5%, 10%, 15%, 20%, 25% to 30% w/w. The results revealed that the VF influenced the density, thermal conductivity and mechanical properties of the VF-PU foams. Specifically, the foam density was inversely correlated with the VF concentration, while the thermal conductivity and the VF content were positively correlated. The increase in the VF content contributed to the deterioration of the mechanical properties because of the development of large closed cells. The results also showed that the 200-mesh VF was the optimal mesh size due to the lowest thermal conductivity. In fact, all the experimental VF-PU foams meet the ASTM C 208 standard, indicating the prospects of mixing the vetiver fibers with polyurethane to produce the environmentally-friendly thermal insulation foams.