Cellulose (2020) 27:6149–6162 https://doi.org/10.1007/s10570-020-03226-2 (0123456789().,-volV) ( 0123458697().,-volV)
ORIGINAL RESEARCH
Using fibre property measurements to predict the tensile index of microfibrillated cellulose nanopaper
. Jonathan Phipps . Stuart Blackburn . Richard Greenwood .
Lewis Taylor David Skuse
Received: 1 December 2019 / Accepted: 9 May 2020 / Published online: 25 May 2020 The Author(s) 2020
Abstract A wide variety of wood and non-wood cellulosic fibre sources were used as a feed to produce microfibrillated cellulose (MFC) using a grinding process. Nanopaper was formed using this product, and the tensile index was measured. The hemicellulose content of the feed fibres was measured, and was found to correlate with the production of finer microfibrils and a higher MFC tensile strength. The correlation with tensile strength was improved by the inclusion of a measurement of the MFC particle lengths as measured by a fibre image analyser, with the resulting relation fitting a modified Page Equation. It was hypothesised that the frequency of flaws in the feed fibre cross-section influences the length of the MFC particles produced, and so the zero-span tensile index of the fibres was measured as a proxy for this since it forces cross-sectional fibre breakage. The fibre zero- span tensile index was found to correlate with MFC particle length and so was used in its place in the Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10570-020-03226-2) con- tains supplementary material, which is available to authorized users. L. Taylor S. Blackburn R. Greenwood D. Skuse School of Chemical Engineering, University of Birmingham, Birmingham B15 2TT, UK L. Taylor ( & ) J. Phipps D. Skuse Par Moor Centre, FiberLean Technologies, Par Moor Road, Par PL24 2SQ, UK e-mail: lxt189@bham.ac.uk; lewis.taylor@fiberlean.com
equation. The resultant equation can predict MFC tensile strength from zero-span tensile index and hemicellulose content measurements of cellulosic fibres and can aid in optimising feedstock selection for mechanical MFC production processes. Microfibrillated cellulose Hemicellulose Zero span tensile strength Tensile strength Keywords
Introduction
Microfibrillated cellulose
Cellulose is an essential structural component in higher plants and is the most abundant polymer on Earth, with an almost inexhaustible supply of around 1.5 9 10 12 tonnes per year produced by biomass (Klemm et al. 2005). Cellulose fibres can be separated from other biomass components by pulping and bleaching processes, producing a cellulose fibre pulp that is used primarily in the production of paper and cellulose-based packaging to impart mechanical strength properties. These mechanical properties are a consequence of the fibre microstructure. Cellulose fibres have a fractal-like structure with several hierarchies of fibre-like sub-units that extend down to the nanoscopic scale. A cellulose fibre consists of parallel chains of
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