title: Relationship between length and degree of polymerization of TEMPO-oxidized cellulose nanofibrils.
abstract: The influence of 2,2,6,6-tetrametylpiperidine-1-oxyl (TEMPO)-mediated oxidation of wood cellulose and the mechanical disintegration of oxidized cellulose in water on degree of polymerization determined by viscosity measurement (DP(v)) and the apparent length of the TEMPO-oxidized cellulose nanofibrils (TOCNs) was investigated. DP(v) values decreased from 1270 to 500-600 with increasing addition of NaClO in the TEMPO-mediated oxidation stage. The DP(v) values were further decreased by mechanical fibrillation in water. There is a linear relationship between the average fibril length and DP(v); the lengths of TOCNs can be approximated from DP(v) using 0.5 M copper ethylenediamine as a solvent of both the cellulose and oxidized celluloses in TOCNs. Based on the cellulose fibril models and TEMPO oxidation mechanism, the depolymerization behavior of TOCNs is tentatively explained in terms of distribution of disordered regions in wood cellulose fibrils and formation of C6-aldehydes in cellulose fibrils during TEMPO-mediated oxidation.
authors.affiliation: Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences,  The University of Tokyo , Tokyo 113-8657, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Shinoda
authors.forename: Tsuguyuki
authors.initials: T
authors.lastname: Saito
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Okita
authors.forename: Akira
authors.initials: A
authors.lastname: Isogai
mesh_terms: D002483:Cellulose, Oxidized / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D058105:Polymerization; D013718:Tensile Strength; D014867:Water / Q000737:chemistry
chemical_list: D002483:Cellulose, Oxidized; D003497:Cyclic N-Oxides; D014867:Water; C003959:TEMPO