Multi-Criteria Optimization of Rice- and Coconut Husks Reinforced Polyurethane Composites as Substitute for Rubber Foam in Air Conditioning

Abstract

This study presents a novel approach to mitigating the environmental impact of non-degradable industrial insulators used in air conditioning pipe. It focused on evaluating and optimizing polymer composites reinforced with rice husks and coconut husks as sustainable thermal insulation materials. This study involved two main phases: First, evaluation of the thermal and mechanical properties of rice and coconut husks reinforced polyurethane composites. Second, determination of the optimal reinforcement ratio using a hybrid multi-criteria decision-making (MCDM) methodology that integrates the Analytical Hierarchy Process (AHP) and the Additive Ratio Assessment (ARAS) techniques. Composites were fabricated with reinforcement ratios ranging from 5% to 25% by weight. Thermal conductivity results, ranging from 0.041 to 0.0486 W/m·K, confirmed the insulative potential of all composite samples, which corresponded to the range reported for industrial thermal insulators. Mechanical testing revealed enhanced tensile strength, particularly with 25 wt% coconut husks, achieving a value of 0.744 MPa. The ARAS method concluded that the optimal composition for insulation performance is 10% rice husk and 25% coconut husk reinforcements. This study advances sustainable thermal insulation materials. In addition, it offers a systematic framework for selecting the optimal reinforcement ratio for biocomposites.