Ultra-sonication assisted cross-linking of cellulose polymers

Inimfon A Udoetok; Lee D Wilson; John V Headley

doi:10.1016/j.ultsonch.2017.12.017

Ultra-sonication assisted cross-linking of cellulose polymers

Ultrason Sonochem. 2018 Apr:42:567-576. doi: 10.1016/j.ultsonch.2017.12.017. Epub 2017 Dec 11.

Authors

Inimfon A Udoetok¹, Lee D Wilson², John V Headley³

Affiliations

¹ Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada.
² Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada. Electronic address: lee.wilson@usask.ca.
³ Water Science and Technology Directorate, Environment and Climate Change Canada, 11 Innovation Boulevard, Saskatoon, Saskatchewan S7N 3H5, Canada.

PMID: 29429704
DOI: 10.1016/j.ultsonch.2017.12.017

Abstract

Cross-linked cellulose-epichlorohydrin polymers were synthesized by a conventional heating with stirring (C-EP heating) and a parallel process using ultra-sonication (C-EP sonication) in the presence of aqueous ammonia. Structural characterization of modified cellulose was carried out using FTIR/¹³C solid state NMR spectroscopy and thermal methods (DSC and TGA). Evidence of products with variable textural properties and morphology was supported by nitrogen gas adsorption, solvent swelling, and microscopy (SEM, TEM) results. C-EP sonication possess greater cross-linker content judging by the loss of the cellulose fibril structure which was facilitated by acoustic cavitation effects due to ultra-sonication. Equilibrium sorption studies in aqueous solution with 2-naphthoxy acetic acid (NAA) revealed that C-EP heating had slightly greater sorption capacity than C-EP sonication at alkaline pH. By contrast, C-EP sonication had greater uptake of NAA at acidic pH. Kinetic uptake studies at pH 3 is described by the pseudo-second order model, where the surface sites of C-EP heating became saturated within ca. 75 min; whereas, ca. 350 min occurred for C-EP sonication. This study demonstrates that the yield of sonication assisted cross-linking of cellulose is greater with improved adsorption properties. The study also reveals the utility of sonication assisted synthesis for the valorization and utilization of cellulose modified materials.

Keywords: Cellulose; Cross-linking; Epichlorohydrin; Sonication; Sorption isotherms.