Xyloglucan films from tamarind kernels reinforced with chemically modified cellulose nanospheres

Globally, over 0.3 billion tons of plastic are produced each year, most of which are non-biodegradable and derived from non-renewable resources. The food packaging sector alone consumes approximately 37.3 million tons annually, contributing significantly to the proliferation of microplastics and nanoplastics, which pose serious risks to both environmental and human health. Agricultural byproducts, such as tamarind kernels, which contain approximately 70 % xyloglucan (TXG), are promising renewable feedstocks for bioplastic production. In this study, TXG was extracted and used to create biopolymer films reinforced with unmodified cellulose nanospheres (U-CNS) and TEMPO-modified cellulose nanospheres (TM-CNS). Rheological analysis of the film-forming solution showed shear-thinning behavior, while FTIR and XRD confirmed successful incorporation of U-CNS and TM-CNS into the TXG matrix. FE-SEM imaging revealed reduced nanoparticle aggregation in TM-CNS films compared with U-CNS films. Adding nanoparticles significantly improved the functional properties of TXG films. Hydrophobicity increased, with the contact angle rising from 31.7° to 81.6°, and moisture content dropped from 19.90 % to 13.69 %. Both U-CNS and TM-CNS increased the tensile strength (TS) of TXG films, raising it from 10.22 MPa to 28.31 MPa, similar to low-density polyethylene (LDPE) films (8-31 MPa). However, U-CNS reduced elongation-at-break (EAB), while TM-CNS maintained flexibility with an EAB of 53.29 % and enhanced strength. Notably, TXG films with 5 % TM-CNS achieved the lowest water vapor permeability (WVP: 2.745 g·mm/day·m²·kPa). Overall, the integration of TM-CNS into TXG films significantly improved mechanical, barrier, and surface properties, demonstrating strong potential for use as sustainable, biodegradable alternatives to conventional plastic packaging.