Aminoethyl substitution enhances the self-assembly properties of an aminocellulose as a potential archaeological wood co
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ORIGINAL ARTICLE
Aminoethyl substitution enhances the self‑assembly properties of an aminocellulose as a potential archaeological wood consolidant Jennifer M. K. Wakefield1,2 · Robert Hampe4 · Richard B. Gillis1,3 · Agnes Sitterli4 · Gary G. Adams3 · Hartmut Kutzke5 · Thomas Heinze4 · Stephen E. Harding1,5 Received: 2 March 2020 / Revised: 5 July 2020 / Accepted: 17 July 2020 © The Author(s) 2020
Abstract The 6-deoxy-6-aminocelluloses—or “aminocelluloses”—are a class of synthetic natural cellulose derivatives which are mostly aqueous soluble and have excellent film-forming properties. Recent studies have connected these properties at the molecular level with protein-like self-associative behaviour for a range of aminocelluloses including a 6-deoxy-6-(ωaminoethyl) aminocellulose AEA-1 with the association being a two-stage process—a reversible oligomerisation followed by further (semi-reversible) aggregation into larger structures. Here, we synthesise and compare a new 6-deoxy-6-(ω-aminoethyl) aminocellulose AEA-1′ with different degree of substitution with one with further alkyl derivatisation, namely 6-deoxy6-(ω-hydroxyethyl) aminocellulose HEA-1′. As with AEA-1, sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge still show a two-stage process for both AEA-1′ and HEA-1′, with the latter giving higher molar masses. The consequences of these properties for use as consolidants for archaeological wood are considered. Keywords Sedimentation velocity · Sedimentation equilibrium · MULTISIG · Hydroxyethyl aminocellulose · Selfassociation
Introduction Special Issue: Analytical Ultracentrifugation 2019. * Jennifer M. K. Wakefield [email protected] * Thomas Heinze Thomas.Heinze@uni‑jena.de * Stephen E. Harding [email protected] 1
National Centre for Macromolecular Hydrodynamics (NCMH), School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
2
School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
3
Queen’s Medical Centre, School of Health Sciences, University of Nottingham, Nottingham NG7 2HA, UK
4
Institut für Organische Chemie und Makromolekulare Chemie, Kompetenzzentrum Polysaccharidforschung, Friedrich-Schiller-Universität Jena, Humboldtstrasse 10, 07743 Jena, Germany
5
Museum of Cultural History, University of Oslo, Postbox 6762, St. Olavs plass, 0130 Oslo, Norway
Cellulose—a ubiquitous natural polymer consisting of glucose units—possesses a variety of interests. The hydroxyl groups present in the polysaccharide backbone make the chemical modification and thus the design of new functional bio-based material accessible (Heinze and Liebert 2012). One possibility for chemical modification is the conversion of the primary hydroxyl group of the glucose unit with p-toluenesulfonyl chloride to obtain cellulose tosylate (Rahn et al. 1996). 6-deoxy-6-aminocellulose (usually called aminocellulose) can be prepared by nucleophilic displacement (SN2 mechanism) of tosylate with amines
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