Thermal Response in Cellulose Iβ Based on Molecular Dynamics

Xuewei Jiang,Lu Zheng,Yu Chen,Yue Yuan

doi:10.1515/cmb-2019-0007

Abstract

Abstract The structural details of cellulose I β were discussed according to molecular dynamics simulations with the GLYCAM-06 force field. The simulation outcomes were in agreement with previous experimental data, including structural parameters and hydrogen bond pattern at 298 K. We found a new conformation of cellulose Iβ existed at the intermediate temperature that is between the low and high temperatures. Partial chain rotations along the backbone direction were found and conformations of hydroxymethyl groups that alternated from tg to either gt or gg were observed when the temperature increased from 298 K to 400 K. In addition, the gg conformation is preferred than gt. For the structure adopted at high temperature of 500 K, major chains were twisted and two chains detached from each plain. In contrast to the observation under intermediate temperature, the population of hydroxymethyl groups in gt exceeded that in gg conformation at high temperature. In addition, three patterns of hydrogen bonding were identified at low, intermediate and high temperatures in the simulations. The provided structural information indicated the transitions occurred around 350 K and 450 K, considered as the transitional temperatures of cellulose Iβ in this work.

Highlights

The research tendency in cellulose and its applications has increased extensively during the past few years (Bergenstrahle et al 2007; Chen et al 2018; Miyamoto et al 2016; Paavilainen et al 2011; Zhang et al 2011)
Thermal response of cellulose Iβ was reported by molecular dynamics simulations with the GLYCAM06 force eld in the present paper
With less than 3.9% deviations of density and unit cell parameters between the data measured in previous experiments and that in our simulation performed at 298 K, the computational methods and selection of force eld in our study was proved with validity for further analysis of the structure

Summary

Introduction

The research tendency in cellulose and its applications has increased extensively during the past few years (Bergenstrahle et al 2007; Chen et al 2018; Miyamoto et al 2016; Paavilainen et al 2011; Zhang et al 2011). As an important natural polymer to industrialization, cellulose can be extracted from various plants and has been widely used to produce materials such as textiles, pulp, biofuels, etc. Cellulosic ber and regenerated cellulosic ber are principal raw materials for textile industry and medical application (Mazeau 2005). Research in the e ect of temperature on the structure and mechanical properties of the cellulose crystal can be signi cant to understanding the fundamental mechanisms of the complex cellulosic self-assembly formation, and for redesigning the sustainable regenerated cellulosic materials with desired performance (Bergenstrahle et al 2007; Zhang et al 2011). Divergent morphologies of cellulose crystals were adopted in nature (Atalla and Vanderhart 1984), and cellulose with crystalline form Iβ constitutes the secondary wall of cotton ber, which is one of the most abundant nature

Methods

Results

Conclusion