School of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China; Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, Nanning 530004, China. Electronic address: [Email]
In this work, cellulase, low-concentration cold alkali and cellulase combined with cold alkali were used to pretreat unbleached bagasse pulp from which cellulose nanofibrils (CNFs), about 30 nm in diameter, were successfully prepared through ultrafine grinding and high-pressure homogenization. X-ray diffraction analysis showed that cellulase pretreatment increased the crystallinity of CNFs. After low-concentration cold alkali pretreatment, the crystallinity of CNFs significantly reduced and the crystal structure of the cellulose changed from type I to type II. Thermogravimetric analysis showed that CNFs prepared by cellulase combined with cold alkali treatment produced more regenerated cellulose and had lower thermal stability. The use of cellulase and low-concentration cold alkali pretreatments combined with ultrafine grinding and high-pressure homogenization is an environment-friendly method for preparing CNFs. The use of low-concentration cold alkali reduces the consumption of alkali and clean water.