title: Effects of ultrasonic treatment during acid hydrolysis on the yield, particle size and structure of cellulose nanocrystals.
abstract: Ultrasonic treatment is useful for the isolation of cellulose nanocrystals (CNCs). However, the effects of ultrasonic treatment on the structure and properties of CNCs have not been fully understood. We statistically analyzed the variations in yields and dimensions of CNCs prepared using acid hydrolysis, with or without ultrasonic treatment, and illustrated these variations by investigating the CNC structures. The results demonstrated that ultrasonic treatment promoted an increase in yields only for short hydrolysis times, while resulting in CNCs with shorter lengths and narrower dimension distributions. Furthermore, a prolonged acid attack under ultrasonic treatment caused a partial dissociation of cellulose hydrogen bond networks in the CNCs, ultimately resulting in the delamination and disorder of the cellulose crystalline structure, thus leading to a decrease in the width and thickness of the CNCs. This work provides more insights into the mechanisms of ultrasonic treatment on the structure and properties of CNCs.
authors.affiliation: Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, PR China; Research Institute for Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, PR China.
authors.forename: Juan
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, PR China.
authors.forename: Xuxia
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, PR China; Center for Renewable Carbon, The University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Siqun
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, PR China; Research Institute for Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, PR China. Electronic address: yafang@caf.ac.cn.
authors.forename: Yafang
authors.initials: Y
authors.lastname: Yin
keywords: Cellulose nanocrystals; Crystal size; Fourier transform infrared spectra; Raman spectrum; Ultrasonic treatment