Cross-linked poly(methyl vinyl ether-co-maleic acid)/poly(ethylene glycol)/nanocellulosics foams via directional freezing.

Affiliation

Department of Chemical & Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN, 37996, USA; Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA; UTK-ORNL Joint Institute for Biological Science, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA. Electronic address: [Email]

Abstract

Aligned micro- and nanoporous materials have gained tremendous interest since they provide great potential in organic electronics, absorbents, biomedicine and tissue engineering. Herein, cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs) cross-linked with poly(methyl vinyl ether-co-maleic acid) (PMVEMA) and poly(ethylene glycol) (PEG) foams were prepared by both the directional and un-directional freezing techniques. Aligned three-dimensional porous structures were observed for the directional frozen foams after lyophilization via scanning electron microscope (SEM). As a result, these highly organized structures exhibited enhanced mechanical performance properties. Particularly, for the 25% CNF foams, the compression modulus increased 60% compared with the un-directional frozen samples. These nanocellulosics-based foams could absorb up to 10-fold water of their initial weight with excellent water stability when immersed in water for more than 48 h. Overall, this study describes a novel process combining cross-linking and directional freezing which successfully fabricates naturally derived foams with anisotropic structure.

Keywords

Cellulose nanocrystals,Cellulose nanofibrils,Cross-linking,Directional freezing,Foams,

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