High shear capillary rheometry of cellulose nanocrystals for industrially relevant processing. (1st March 2020)

• Record Type: Journal Article
• Authors: Sutliff, Bradley P.; Das, Arit; Youngblood, Jeffrey; Bortner, Michael J.
• Is Part Of: Carbohydrate polymers. Volume 231(2020)
• Publication Date: 2020-03-01
• Subjects: Cellulose nanocrystal (CNC) suspensions -- High shear rate rheology -- Time-temperature superposition -- Time-concentration superposition; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2019.115735
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: First high shear rate capillary rheology of CNCs. Aqueous CNC suspensions obey a time-temperature superposition relationship. High shear rate viscosities approach a secondary Newtonian plateau. High shear rates can alter the shape and viscosity of cellulose nanocrystals. Abstract: A microcapillary rheometer was employed to study the rheological characteristics of CNCs at temperatures between 15 °C and 50 °C and aqueous concentrations between 1.5 wt% and 12.1 wt%, at rates up to 8 × 10 5 s −1 . Time-temperature and time-concentration superposition were applied to analyze the data. A master curve of shear rate sweeps at temperatures between 15 °C and 50 °C was successfully generated to a reference temperature of 25 °C with the shift factor plot suggesting an Arrhenius relationship over the entire measured temperature range. Concentration-dependent data indicate a high shear Newtonian plateau at the limit of low concentration. Repeated testing of the same sample volume was implemented to represent extended times at elevated stress, with repeated experiments leading to a permanent decrease in viscosity. Atomic force microscopy (AFM) suggests sensitivity of the CNC geometry to moderate stress in a flow field.