On the polymorphic and morphological changes of cellulose nanocrystals (CNC-I) upon mercerization and conversion to CNC-II

Research output: Contribution to journalArticle

Researchers

Research units

  • Nanjing Forestry University

Abstract

Polymorphic and morphological transformations of cellulosic materials are strongly associated to their properties and applications, especially in the case of emerging nanocelluloses. Related changes that take place upon treatment of cellulose nanocrystals (CNC) in alkaline conditions are studied here by XRD, TEM, AFM, and other techniques. The results indicate polymorphic transformation of CNC proceeds gradually in a certain range of alkali concentrations, i.e. from about 8% to 12.5% NaOH. In such transition alkali concentration, cellulose I and II allomorphs coexists. Such value and range of the transition concentration is strongly interdependent with the crystallite size of CNCs. In addition, it is distinctively lower than that for macroscopic fibers (12-15% NaOH). Transmission electron microscopy and particle sizing reveals that after mercerization CNCs tend to associate. Furthermore, TEMPO-oxidized mercerized CNC reveals the morphology of individual nanocrystal of the cellulose II type, which is composed of some interconnected granular structures. Overall, this work reveals how the polymorphism and morphology of individual CNC change in alkali conditions and sheds light onto the polymorphic transition from cellulose I to II.

Details

Original languageEnglish
Pages (from-to)327-335
Number of pages9
JournalCarbohydrate Polymers
Volume143
Publication statusPublished - 5 Jun 2016
MoE publication typeA1 Journal article-refereed

    Research areas

  • Cellulose I and II, Cellulose nanocrystals, CNC, Crystallinity, Crystallite size, Mercerization, Polymorphs

ID: 1709353