作者：Llyza Mendoza^a, Warren Batchelor^a, Rico F.Tabor^b, Gil Garnier^a 

^a Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, VIC 3800, Australia

^b School of Chemistry, Monash University, VIC 3800, Australia

 

摘要：

Hypothesis

Nanocellulose gels form a new category of sustainable soft materials of industrial interest for a wide range of applications. There is a need to map the rheological properties and understand the mechanism which provides the colloidal stability and gelation of these nanofibre suspensions.

Experiments

TEMPO (2,2,6,6,-tetramethylpiperidine-1-oxyl)-oxidised cellulose nanofibre gels were investigated at different fibre concentrations, pH and ionic strength. Dynamic and cyclic rheological studies was performed to quantify gel behaviour and properties. Gels were produced at different pH and salt contents to map and understand colloidal stability of the nanocellulose gel.

Findings

Rheology indicates gelation as a transitionary state starting at a fibre concentration of 0.1 wt.%. The colloidal stability of the nanocellulose gel network is controlled by pH and salt, whereas fibre concentration mainly dictates the dynamic rheological properties. Decreasing pH and adding salt destabilises the gel network by eluting bound water which is correlated with the decrease in electrostatic repulsion between fibres. The gelation and colloidal stability of these nanocellulose gels is driven by electrostatic forces and the entanglement ability of the fibrous system to overlap.