Mechanical and Thermal Properties of Polyurethane Composites Reinforced with Giant Reed Fiber (Arundo donax) and Recycled Post-Industrial Polyurethane

Abstract

This study analyzes the development and characterization of hybrid polyurethane composites reinforced with agro-industrial residues of Arundo donax and recycled polyurethane. Formulations were prepared with different reinforcement concentrations (10%, 15%, and 20%) and alkaline treatments (0%, 5%, and 10% NaOH). Their mechanical performance was evaluated through tensile and flexural tests, while their thermal behavior was assessed via thermal conductivity measurements. The results revealed that the formulation containing 15% reinforcement and a 5% alkaline treatment (B2) achieved the highest flexural strength (0.58 MPa), indicating efficient interfacial interaction between the fibers and the matrix. Furthermore, all reinforced formulations exhibited lower thermal conductivity values than the unreinforced polyurethane (0.166 W/m·°C), confirming their potential as thermal insulation materials. These findings demonstrate the feasibility of utilizing lignocellulosic and polymeric residues to produce sustainable bio-composites, contributing to the development of materials with enhanced mechanical and thermal properties and promoting the circular economy.