Evaluating the performance of biopolyol-based rigid foams derived from rice straw liquefaction

Purpose – The polyurethane sector primarily relies on petrochemical substances, including polyols and isocyanates. Given the swift consumption of fossil fuel resources and the rising concerns about ecological issues and global warming, this study aims to explore the sustainable advancement of polyurethane rigid foam by using renewable biopolyols derived from agricultural waste liquefaction. Design/methodology/approach – The liquefaction of lignocellulosic biomass involves breaking down complex polymers into smaller molecules using heat, chemicals and catalysts to prepare biopolyol as a renewable feedstock for the polyurethane industry. Spectral analysis of the liquefaction products verified that the process achieved the desired outcome and indicated the presence of hydroxyl groups. The biopolyol analysis demonstrated a biomass conversion rate of up to 87% and a hydroxyl number between 230 and 250 mg KOH/g, suggesting that this biopolyol could serve as a viable alternative to petrochemical polyols. Findings – Various formulations of biopolyol obtained from rice straw liquefaction, conducted at 160 °C for 2 h, were prepared. Intensive study was conducted on the applicability of using biopolyol in rigid foam refrigerator formulation in comparison to petroleum counterparts. The results obtained from scanning electron microscopy showed that the biopolyol-based foams had a symmetrical cell structure and a significant proportion of sealed cells. Biobased foam demonstrated superior thermal insulation compared to its petrochemical-based equivalent. Originality/value – These results underscore the feasibility of agricultural waste liquefaction as an eco-friendly approach for synthesizing biopolyols and their application in polyurethane foam production. The study contributes to the development of sustainable materials in the polymer industry and supports the transition toward renewable feedstocks in rigid foam applications. The study, moreover, introduces PEG 400 as a novel liquefaction solvent, offering improved compatibility with rigid polyurethane systems and establishing a new benchmark for sustainable rigid foam production.