Location: Cotton Structure and Quality Research
Title: Estimation of the Young’s modulus of cellulose Iß by MM3 and quantum mechanics Author
|Santiago Cintron, Michael|
Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: December 17, 2010
Publication Date: March 27, 2011
Citation: Santiago Cintron, M. 2011. Estimation of the Young’s modulus of cellulose Iß by MM3 and quantum mechanics. American Chemical Society National Meeting. CELL: 281. Technical Abstract: Young’s modulus provides a measure of the resistance to deformation of an elastic material. In this study, modulus estimations for models of cellulose Iß relied on calculations performed with molecular mechanics (MM) and quantum mechanics (QM) programs. MM computations used the second generation empirical force field MM3; a force field that considers the anomeric effect. MM3 and QM computations (B3LYP/6-311G**+) with a disaccharide cellulose model and an analogue incapable of making hydrogen bonds revealed a considerable contribution of intramolecular forces to the molecular stiffness of cellulose Iß. MM3 calculations with longer cellulose chains (10-40 glucose units) models resulted in modulus values, 126.0-146.7 GPa, comparable to reported modulus values for cellulose Iß crystallites. Additional calculations with extended-chain analogues corroborated the observed stiffness conferred by intramolecular hydrogen bonds. In contrast, modulus determinations with models containing multiple cellulose chains were not strongly affected by intermolecular hydrogen bonding.