Cellulose nanocrystals (CNCs) derived from dyed and bleached cotton-based textile waste

Bio-based nanomaterials such as cellulose nanocrystals (CNCs) have been increasingly explored in nanotechnology owing to their chemo-physical properties, self-assembly, and low toxicity. Introduction: CNCs can be isolated from various cellulosic biomass sources. Textiles made of natural fibers, which are mostly made of cotton, are under-utilized biomass that after their lifetime is either burned or dumped into landfills. In this study, cotton-based textiles are studied as a source of CNCs. CNCs were extracted from textiles without and with bleaching before the acid hydrolysis step, and further comparing them with the properties from industrial microcrystalline cellulose-derived CNCs. Nanocrystals were synthesized from the three different sources and their morphology, thermal properties, and colloidal stability were compared. The findings show similar thermal properties and morphological characteristics for the three synthesized CNCs, and similar colloidal stability between the two textile-based CNC dispersions, suggesting that the dyes on CNCs do not impact the quality of the product. Removing the bleaching pretreatment –a water-demanding and toxically harmful step– before CNC extraction provides cost and environmental benefits without compromising on the CNC quality. This project seeks to streamline the CNC synthesis process with the long-term goal of eventually facilitating the textile recycling industry.