Facile nanofibrillation of strong bamboo holocellulose via mild acid-assisted DES treatment

Abstract

A facile and sustainable strategy for preparing bamboo holocellulose nanofibrils (HCNFs) via zinc acetate/ choline chloride deep eutectic solvents treatment assisted with mild acetic acid (HAc) was developed in the present work. The treatment was performed under fast microwave irradiation and followed by mechanical homogenization , resulting in HCNFs with considerable amounts of xylan hemicellulose (15 %−19 %) remained. Less HAc consumption was achieved, which is beneficial for fabricating nanofibrils with higher aspect ratios (>800). More xylan contents and higher degrees of acetylation on cellulose were investigated, resulting in greater charge repulsion and steric hindrance between HCNFs and favoring the fibrils dissociation. Moreover, the HCNFs maintained high crystallinity of 70 %− 80 % and good thermal stability, confirming the intact hydrogen bonding linkages between cellulose and xylan hemicellulose. Transparent films prepared from the HCNFs suspensions by vacuum drying approach displayed better mechanical strength (>40 MPa) and well-mimicked the complex of polysaccharides interactions in plant cell walls. • Bamboo HCNFs were prepared by ZnAc/ChCl DES with mild HAc and microwave assistance. • Acetylation and charge repulsion favored the holocellulose nanofibrillated. • Higher DES ratios fabricated HCNFs with greater aspect ratios and xylan content. • HCNFs films present high transparency and improved mechanical strength.