Performance enhancement of coir fiber-reinforced elastomeric polyurethane eco-composites via the enrichment of fiber surface using sustainable modifications

Tuning the chemical functionality of lignocellulosic fiber plays a key role in the development of mechanically strong composites to overcome the leakage of compatibility between composite phases which is a major challenge in multidimensional applications of eco-composites. Herein, the coconut fiber (CF) surface was enriched via four kinds of modification routes including mercerization, amino-functional silane treatment, bio-based epoxy resin sizing, and isocyanate treatment to enhance its interfacial adhesion to thermoplastic polyurethane (TPU) matrix. Tensile strength and Shore-hardness parameters of composites were improved by surface-modified CF inclusions. Thermo-mechanical response of TPU was optimized after CF loadings regardless of treatment type. Composite involving silane-modified CF exhibited the lowest water uptake due to the hydrophobic behavior of the silane layer. The increase in interfacial interaction between the TPU matrix and modified CF was confirmed by SEM investigations. The chemically enriched surface of CF confers the performance of composites thanks to improved adhesion in the TPU-CF interface.