Molecular modeling of cellulose in amorphous state. Part I: model building and plastic deformation study

Molecular modeling was utilized to provide insight into the yielding behavior and poor recovery from applied strain for cellulose. Amorphous cellulose models were successfully built and examined with the use of force field pcff_300_1.01. High-temperature molecular dynamics, followed by minimization, was used to generate relaxed structures for amorphous cellulose. Properties related to inter-molecular interactions were calculated for these models and found to be comparable with literature values. The observed yielding for these models, which occurred at approximately 7–8% strain, was found to be due to the disruption of hydrogen bonds between cellulose chain segments. New hydrogen bonds were formed in extension but only 1/3 of these were broken during recovery. These newly formed hydrogen bonds were found to hold the cellulose chain segments in the new positions thus resulting in poor deformation recovery.