title: Bulky quaternary alkylammonium counterions enhance the nanodispersibility of 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized cellulose in diverse solvents.
abstract: The degree of nanodispersion of cellulose in diverse solvents is a significant primary criterion for the preparation of bulk nanocelluloses and nanocellulose-containing composites. Here, high degrees of nanodispersion of fibrous 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized cellulose (TOC) were achieved in various solvents by efficiently incorporating quaternary alkylammoniums (QAs) as counterions of TOC carboxyl groups via simple ion-exchange treatment in water. Tetramethyl-, tetraethyl-, tetra-n-propyl-, and tetra-n-butylammoniums were used as the QAs. The TOC-QAs were converted to TOC nanofibrils (TOCN-QAs) with a high nanofibrillation yield via mechanical disintegration in not only water but also methanol and other organic solvents after solvent-exchange treatment. Fourier transform infrared spectra of cast TOCN-QA films and the electric conductivities of the TOCN-QA dispersions indicated that the TOCNs-QAs were dispersed primarily through dissociation of the bulky QA carboxylate groups. Moreover, the TOC-QAs were nanodispersible in water even after being oven dried at 105 °C, which is advantageous for their practical application.
authors.affiliation: Department of Biomaterials Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo , Tokyo 113-8657, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Shimizu
authors.forename: Tsuguyuki
authors.initials: T
authors.lastname: Saito
authors.forename: Akira
authors.initials: A
authors.lastname: Isogai
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry*; D015394:Molecular Structure; D057139:Nanofibers / Q000737:chemistry*; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry
chemical_list: D003497:Cyclic N-Oxides; D000644:Quaternary Ammonium Compounds; D012997:Solvents; D002482:Cellulose; C003959:TEMPO