Swelling kinetics of cellulose / chondroitin sulfate membranes crosslinked with borax

The use of by-products from the wood industry as an alternative to obtaining cellulose, using an eco-friendly process is essential for the sustainable production of high value-added bioproducts. In this research, the cellulose/chondroitin sulfate membranes were obtained using saw dust as the cellulose source. Initially, cellulose was extracted using peracetic acid (PA) in one (Cel1) and two cycles (Cel2) and mercerized with NaOH. Analysis of the products obtained by X-ray diffraction (WAXD), Fourier transform infrared spectroscopy (FTIR) and Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS) confirmed that the extracted cellulose was type II and that the reduction of lignin (from 36 to 3.5%) did not depend on the number of bleaching cycles. Membranes with and without the addition of borax were obtained by dissolving cellulose in NaOH/urea/H2O (7/12/81% m/m), mixed with chondroitin sulfate (SC) in proportions 100/0; 90/10; 80/20 and 70/30 (% m/m). The effect of SC contents and the presence of borax on the properties of membranes produced was investigated. The results showed that the swelling ratio, equilibrium water content and kinetic mechanism of water absorption were influenced by the presence of borax and the amount of chondroitin sulfate. The results demonstrated that the properties of Cel/SC membranes could be modulated by the composition and had potential for application in the biomedical area.