Effect of xylanase-assisted pretreatment on the properties of cellulose and regenerated cellulose films from sugarcane bagasse

摘要

A two-stage pretreatment process using alkaline and xylanase-assisted pretreatments was studied and compared to one-step alkaline pretreatment to investigate the effect of xylanase-assisted pretreatments on the properties of fibers and regenerated cellulose films. The alkaline-xylanase bleached fibers (AXB-fibers) could reduce bleaching time from 6 to 4 times to obtain an 83.3% whiteness index. A substantial proportion of the cellulose content (83%) was successfully extracted from sugarcane bagasse using the two-step process. Moreover, the fiber had an increased crystallinity index and thermal stability. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) revealed that hemicellulose and lignin were removed from the sugarcane bagasse (SCB) structure during the cellulose extraction process. The alkaline bleached fibers (AB-fibers) and AXB-fibers were dissolved in 1-butyl-3-methylimidazolium chloride, and regenerated cellulose films, AB-films and AXB-films, respectively, were prepared from the solutions. SEM images showed that both cellulose films were homogeneous and had a smooth surface. FTIR and X-ray diffraction (XRD) analyses corroborated that the transition from cellulose I to cellulose II occurred during the dissolution and regeneration process. Furthermore, the AXB-films displayed higher thermal stability and mechanical properties (258 degrees C and 90.43 MPa for the onset temperature and tensile strength, respectively) than those of the AB-films. (C) 2018 Elsevier B.V. All rights reserved.