Influence of Organic Liquids on the Nanostructure of Precipitated Cellulose

Published

February 15, 2013

Author(s)

Brian J. Watson, Boualem Hammouda, Robert M. Briber, Steven W. Hutcheson

Abstract

Cellulose (β-1,4 glucose) crystallinity poses a substantial physical and economic barrier to the enzymatic digestion of biomass to its constituent sugars. The crystallinity of cellulose is an inherent property due to its synthesis as microfibrils as plant cell walls are assembled. Conventional pretreatment technologies generally do not affect cellulose crystallinity or only cause a transient decease in cellulose crystallinity that diminishes upon washing in water. Using the Flory-Huggins solvent-polymer interaction parameter to predict solvent compatibility with cellulose, water turned out to be a poor solvent for cellulose while several alcohols and glycols were identified as good solvents for cellulose. To test these solvents, cellulose was first solubilized using phosphoric acid was then washed with the candidate solvents to remove the phosphate. In contrast to water which precipitates cellulose, cellulose formed an apparent gel in several of these alternative solvents. These solvents reduced the optical and physical density of these apparent cellulose gels and decreased the thermal stability and scattering intensity in small angle neutron scattering (SANS). Fractal analysis of the SANS data from these apparent gels indicates that cellulose polymers in these solvents have scaling properties of a Gaussian chain in solution consistent with disruption of cellulose crystallinity. Enzyme digestion of the solvent-treated, water-equilibrated material increased approximately 30 % relative to cellulose that was directly washed in water. Two exceptions to the predictions of compatible solvents were noted which appeared to be due to their hydrogen bonding properties. The results indicated that solvent manipulation can be used as part of a pretreatment process to enhance digestibility by cellulases.

Citation

Journal of Applied Polymer Science

Volume

127

Issue

4

Pub Type

Journals

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Keywords

cellulose, small-angle neutron scattering, biomass, solubility

Citation

Watson, B. , Hammouda, B. , Briber, R. and Hutcheson, S. (2013), Influence of Organic Liquids on the Nanostructure of Precipitated Cellulose, Journal of Applied Polymer Science, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=906635 (Accessed October 6, 2024)