Aproveitamento do resíduo de algodão da indústria têxtil para síntese de hidrogel de celulose

Abstract

Brazil is one of the largest exporters of cotton globally and a major producer of 100% cotton textile products such as fibers, yarns, woven, and knitted fabrics. The production of these goods involves a complex chain with various stages that significantly impact the environment. One major impact is the generation of cellulose-rich textile waste, one of the most abundant natural polymers on the planet. Cellulose offers crucial properties: high absorption capacity, mechanical strength, water insolubility, elasticity, and biodegradability. This absorption capacity is essential for developing and manufacturing hydrogels, a widely used biomaterial. This study aims to produce hydrogel using cellulose powder, a waste generated during the sanding of cotton fabric used for denim, commonly known as jeans, in the textile finishing stage. To obtain the hydrogel, the waste was dissolved in a solution of 6% NaOH and 4% urea at 50°C, under agitation at 650 rpm for 30 minutes. Subsequently, it was crosslinked with epichlorohydrin and post-treated by freezing or heating. To obtain the hydrogel, the waste was dissolved in a solution of 6% NaOH and 4% urea at 50°C, under agitation at 6.5 rpm for 30 minutes. The results indicate that hydrogel production depends on the concentration of the substrate and crosslinker. The optimal formulation was 1g of cellulose with 9ml of epichlorohydrin, post-treated by heating. SEM-FEG results confirmed increased cellulose porosity, enhancing the hydrogels' absorption capacity. XRD demonstrated peaks corresponding to the transition from cellulose I to cellulose II crystalline structures. FTIR detected the presence of key organic chemical groups, such as hydroxyls, and an increase in carboxylic groups, confirming successful crosslinking with epichlorohydrin. TGA identified the main degradation stages and temperatures of the cellulose in the hydrogel. Finally, DSC analysis showed the interaction between water and cellulose, with exothermic events indicating higher amounts of epichlorohydrin in the hydrogels. These findings suggest that cellulose waste has significant potential for large-scale hydrogel production.