title: Mixed 3-mono-O-alkyl cellulose: synthesis, structure characterization and thermal properties.
abstract: The 3-mono-O-alkyl cellulose samples bearing two different ether moieties, namely methyl/ethyl, methyl/n-propyl, and ethyl/n-propyl were synthesized applying protecting group technique. The NMR spectra of the peracetylated products revealed the regioselectivity of the alkylation as well as the degree of substitution of both alkyl moieties. The number average degree of polymerization (DPn) monitored by size exclusion chromatography decreases from DPn 117 (Avicel PH-101, starting material) to DPn 34 (sample 4f) due to the multi-step synthesis. It could be demonstrated that the lower critical solution temperature (LCST) is influenced by the degree of substitution of both alkyl groups. For example, LCST values between 33 and 58 °C were measured for aqueous solutions of 3-mono-O-ethyl/n-propyl cellulose. On the contrary, the thermal behavior of a physical mixture of 3-mono-O-ethyl- and 3-mono-O-n-propyl cellulose, e.g., was controlled by the derivative with the lowest LCST.
authors.affiliation: Friedrich Schiller University of Jena, Institute for Organic Chemistry and Macromolecular Chemistry, Center of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany; Åbo Akademi University, Fibre and Cellulose Technology, Porthansgatan 3, FI-20500 Åbo, Finland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Heinze
authors.affiliation: Friedrich Schiller University of Jena, Institute for Organic Chemistry and Macromolecular Chemistry, Center of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany.
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Friedrich Schiller University of Jena, Institute for Organic Chemistry and Macromolecular Chemistry, Center of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Koschella
authors.affiliation: University of Nottingham, Division of Food Sciences, School of Biosciences, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom.
authors.forename: Antonio
authors.initials: A
authors.lastname: Sullo
authors.affiliation: University of Nottingham, Division of Food Sciences, School of Biosciences, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom.
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Foster