New Polyurethane Biocomposites Based on Cellulosic Fibers: Effect of the Cellulose Content on the Composite Thermomechanical Properties

Two polyurethane (PU) matrices were synthesized using poly(ε‐caprolactone) diol and 4,4′‐diisocyanato dicyclohexylmethane using two different synthetic approaches. NMR and FTIR spectroscopy analysis ensured the chemical structure and the formation of the matrices. Thereafter, composite materials were prepared by incorporating cellulose fibers into the PU matrix having the higher molecular weight. FTIR revealed interactions between the polyurethane and the cellulose fibers, suggesting good interfacial compatibility. DSC study evidenced that an increase in the incorporated cellulose percentage led to an increase in the T g value of the obtained composites ranging from −49.3°C to −40.5°C. TGA analysis shows that these composites were thermally stable up to 266°C. Mechanical data indicate a progressive enhancement in rigidity with increasing fiber content, highlighting the enhancing effect of the cellulose within the polymer matrix. These results show the potent use of this composite family for applications that require both mechanical robustness and thermal stability.