Abstract
The rheological behaviour of homogenised fibres originally having different lengths was evaluated. For this purpose, mixtures of pulp fibres and fines were fibrillated mechanically without pre-treatment and characterised with regard to morphology and viscosity. It was found that, for all samples, a similar number of homogenisation passes was needed to reach a viscosity plateau. However, the value of the final viscosity differed significantly: homogenised suspensions derived from fines achieved only about 60 % of the viscosity of suspensions derived from pulp. Already after a few homogenisation cycles, no differences between the samples could be measured using optical devices, indicating that fibrillation on the nanometre scale was responsible for the distinct rheological behaviours. Atomic force microscopy measurements indicated significantly reduced fibril lengths for the suspensions derived from fines, which explains their reduced viscosity.
Highlights
The rheological behaviour of homogenised fibres originally having different lengths was evaluated
We evaluate cellulose nanofibrils derived from secondary pulp fines and compare the differences in morphology and rheology of cellulose nanofibrils derived from different mixtures of fibres and fines
It should be stated that the atomic force microscopy (AFM) technique gives only very local information about a finite number of fibrils which cannot be considered as representative for the whole sample
Summary
The rheological behaviour of homogenised fibres originally having different lengths was evaluated. For this purpose, mixtures of pulp fibres and fines were fibrillated mechanically without pretreatment and characterised with regard to morphology and viscosity. The definition of fines may slightly vary depending on the standard used: they are e.g. defined as the fibres passing a round hole 76 lm in diameter (TAPPI 1994; ISO 2012) or as the particles shorter than 200 lm (ISO 2014). For practical reasons, the latter definition was used in this study.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
