Effect of Cellulose Chain Extender on the Molecular, Thermal, and Mechanical Characteristics of Polyurethane Foam

Abstract

This study investigates the incorporation of cellulose as a bio-based modifier into polyurethane foam and its effects on molecular interactions, morphology, thermal behavior, and mechanical performance. Polyurethane foam was synthesized using polypropylene glycol (PPG 2000), toluene diisocyanate (TDI), water, and cellulose at 1, 2, and 3 wt.%. Fourier-transform infrared (FTIR) spectroscopy confirmed urethane formation and suggested subtle intermolecular interactions between cellulose and the polyurethane matrix. Scanning electron microscopy (SEM) revealed predominantly open-cell morphology, with improved cell uniformity 2 wt.% cellulose loading. Thermal analysis showed that cellulose incorporation slightly modified the endothermic transition behavior while reducing the degradation onset temperature and Tmax from 390.16 to 377.13 °C, indicating a narrower thermal stability window. Mechanical testing demonstrated that the tensile strength increased to 0.085 MPa at 2 wt.% cellulose before decreasing at higher loading, whereas the elongation at break declined due to restricted chain mobility. These findings demonstrate that controlled cellulose incorporation can tailor the mechanical performance and morphology of polyurethane foams, supporting its potential use as a sustainable bio-modified polymeric material.