Molecular Dynamics Study of Hydrogen Bond Structure and Tensile Strength for Hydrated Amorphous Cellulose.

Molecular dynamics (MD) simulations were conducted to investigate the hydrogen-bond (H-bond) structure and its impact on the tensile strength of hydrated amorphous cellulose. The study identifies a stable intramolecular H-bond between the hydroxyl group at position 3 and the ether oxygen at position 5 (OH3···O5). Intermolecularly, the hydroxyl groups at positions 2 (OH2) and 6 (OH6) form stable H-bonds. Young's modulus, maximum tensile strength, and corresponding strain were calculated as functions of moisture content, while the H-bond network, water cluster formation, and cellulose chain orientation during tensile simulations were analyzed to elucidate mechanical properties. The substitution effect of cellulose on Young's modulus is also examined, revealing that the substitution of OH3 for a hydrophobic group minimally affects Young's modulus, but substitutions at OH2 and OH6 significantly reduce tensile strength due to their roles as key intermolecular H-bond donor sites.