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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Cotton Structure and Quality Research » Research » Publications at this Location » Publication #250335
Title: Preliminary modulus calculations for cellulose

Author
item Santiago Cintron, Michael
item French, Alfred - Al
item Johnson, Glenn

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/10/2010
Publication Date: 4/28/2010
Citation: Santiago Cintron, M., French, A.D., Johnson, G.P. 2010. Preliminary modulus calculations for cellulose. Proceedings of the National Cotton Council Beltwide Cotton Conference, January 5-7, 2010, New Orleans, Louisiana. p. 1564-1568.

Interpretive Summary: The Young's modulus is a measure of the resistance to deformation of a flexible material. In the case of cellulose, it quantifies the ability of the material to undergo changes in length as elongation or compression forces are applied. The modulus can be calculated by performing stretching tests on cotton fibers or, as in this study, by stretching molecular models in a computer program. However, considerable differences between values from different experimental stretching tests and among molecular modeling calculations are observed. With this study we attempt to establish the roles of intermolecular hydrogen bonding and other molecular details in computer-based modulus determinations. To achieve this, modulus calculations with molecular mechanics and quantum mechanics were performed with short-form cellulose models capable of intramolecular hydrogen bonds, as well as, some related models in which hydrogen bonding was eliminated. Preliminary results suggest that intramolecular hydrogen bonding contributes considerably to the resistance to deformation observed in cellulose.

Technical Abstract: The Young's modulus is a measure of the inherent stiffness of an elastic material. In the case of cellulose, it quantifies the ability of the material to undergo changes in length as tension or compression forces are applied. The modulus can be calculated by performing tensile tests on cotton fibers or, as in this study, by stretching molecular models in a computer program. However, considerable disparities between values from different experimental tensile tests and among molecular modeling calculations are observed. With this study we attempt to ascertain the roles of intermolecular hydrogen bonding and other intra- and intermolecular details from molecular models in modulus determinations. To achieve this, modulus calculations with empirical force fields and quantum mechanics were performed with cellobiose models capable of intramolecular hydrogen bonds as well as some analog models that cannot make hydrogen bonds.