Preparation of polymer brush-type cellulose β-ketoesters using LiCl/1,3-dimethyl-2-imidazolidinone as a solvent

• Published in: Polymer (Guilford) Vol. 46; no. 8; pp. 2548 - 2557
• Main Authors: Yoshida, Yutaka, Yanagisawa, Masahiro, Isogai, Akira, Suguri, Nobuhiko, Sumikawa, Naomi
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 24.03.2005; Elsevier
• Subjects: Applied sciences; Cellulose and derivatives; Cellulose derivatives; Cellulose solvent; Exact sciences and technology; Ketene dimer; Natural polymers; Physicochemistry of polymers; Ketene dimer; Cellulose solvent; Cellulose derivatives; Chemical solution; Cellulose; Fatty ester; Radius of gyration; Experimental study; Ketenes; Esterification; Lateral group; Molecular weight property relation; Thermal stability; Homogeneous reaction; Chemical modification; Preparation; Cellulose organic ester; Ketoester; Growth from solution; Conformation
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2005.01.050

Cellulose β-ketoesters with branched alkenyl chains were prepared using cis-9-octadecenyl ketene dimer (OKD) and LiCl/1,3-dimethyl-2-imidazolidinone (DMI) as the esterifying reagent and cellulose solvent, respectively. Relationships between degree of substitution (DS) of the cellulose/OKD β-ketoesters and reaction conditions were studied in detail. The results showed that DS values of the products were controllable up to 2.1 by selecting the reaction conditions. Solution- and solid-state 13C-NMR analyses revealed that cellulose backbones of the cellulose/OKD β-ketoesters with DS 2.1 behave like solid in chloroform owing to strong restriction on movement of cellulose chains by the long and branched alkenyl substituents introduced. Size-exclusion chromatographic analysis showed that little depolymerization occurred on cellulose during β-ketoesterification at room temperature, and that molecules of the cellulose/OKD β-ketoesters with DS 2.1 had semi rigid-rod conformation in tetrahydrofuran. Thus, cellulose β-ketoesters with densely substituents like polymer brushes or comb-shaped polymers were prepared in this study.