CSA Z5300:19 pdf free download.Cellulose filaments (CF) – Preparing handsheets for physical tests.The size is 25.3M.
0.1 Cellulose filaments, microfibrils, and nanofibrils
The need to develop high-value applications of wood pulp fibres has prompted significant efforts by the Canadian pulp and paper industry to develop the production of cellulose nanomaterials(CNM)derived from pulp fibres and improve their unique properties.
To this end, microfibrillated cellulose( MFC) now called cellulose microfibrils( M F)， was first produced in the 1980s by multi-pass, high-pressure mechanical disintegration of pulp fibres at 2 to 4 wt% consistency in a homogenizer 1, 2] A very high energy input is required to delaminate the pulp fibres, prohibiting CMF production at an industrial scale. Currently, many alternative multi-pass processes are used to produce CMF and cellulose nanofibrils(CNF)， including homogenization, microfluidization,grinding, and low-or medium-consistency refining, often coupled with chemical or enzymatic pre-treatments to reduce the amount of mechanical energy required to generate the fibrils and prevent clogging of the equipment. The typical processing consistency to produce CMF and CNF is about 3 wt% or less.
For the purposes of this Standard, CMF are fibrils(fibre-like strands)composed of cellulose and having cross-sectional dimensions typically larger than 100 nm, while CNF are fibrils of cellulose having cross- sectional dimensions in the nano-scale; that is, between 1 and 100 nm. Both CMF and CNF have lengths of typically less than 100 um 3-5] and aspect ratio(length-to-width ratio)generally in the range of 10 to 150 [6]。 Owing to large variations in the manufacturing processes used to produce them, material designated as CMF can contain a certain(small) fraction of CNF, and vice versa.
Recently, commercially feasible industrial-scale processes to produce cellulose filaments( CF)have been leveloped. CF are produced from wood pulp by applying mechanical forces, for example, using multi pass disk refining at a high consistency of> 20 wt%， without chemical or enzymatic pre-treatment.
CF is a CNM consisting of individual cellulose filaments or fibrils having a flexible ribbon-like structure Figure 1)， with a length typically> 100 um on average. Its cross-sectional dimensions generally range from 30 to 500 nm, giving CF a very high aspect ratio of at least 200 and typically> 500(7, 8. CF is thus much longer than CMF or CNF (see Figure 2).
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