Fibre fineness

Jaycock, M.J. et al.. Effect of cellulose fibre fines on the retention of fillers, J. Appl. Chem. Biotechnol., 26, 370, 1976. 

Fig. 3.7 Mutek DFR-04 (Photo courtesy of BTG). The Miitek DFR-04 Drainage Retention Freeness tester is the first laboratory unit that automatically detects the retention of fibres, fines and fillers. Within a few minutes it can be changed for drainage as well as freeness measurements. Advanced hardware and software allows simulation of paper machine conditions and evaluation of drainage and retention aids ...

It is essential to remove this water in order to break the particle and aUow the AKD wax to melt, spread and react with the fibre. Retention of the AKD can be improved by the use of additional cationic starch, or cationic polymers. The starch, or polymer, may be added separately, or included in the emulsion with the AKD wax. The role of this additional starch, or polymer, can be to stabilise the AKD dispersion, but is often more of use as an anionic trash collector (ATC) as it is more cationic than the AKD itself and will neutralise the anionic trash, allowing the AKD to be preferentially adsorbed on fibres, fines and fillers, increasing the retention of the AKD wax. If incorporated into the dispersion for stability, the ronoval of the polymer to act as an ATC will destabilize the dispersion, allowing it to break more quickly in the drying section and thus increase the reaction of the AKD with the fibre. 

The AKD and ASA particles are cationic in nature and covered (see Fig. 5.7) by a layer of colloid (starch or polymer) which protects them from the harsh realities of hot stock conditions. As long as the protective layer is not broken and the particles are still firmly fixed to the fibres/fines, they will remain unaffected. However, at temperatures above 60-70 C the particles begin to lose stability. For AKD, this is above its melting range of45-60 C, and similarly for ASA, where the ASA begins to become more mobile within its particle. If the particles break, then the AKD and ASA are exposed to heat and water at alkaline pH, which hydrolyses them extremely rapidly - ASA more rapidly than AKD. 

Fibres (mean fineness) Fibres (fine) Microfibres Super-microfibres... 

Nearly all retention aid systems used in paper manufacturing contain a high-molecular-weight polymer as a key component. The adsorption of polymers at the surfaces of fibres, fines and fillers in the papermaking... 

Type of fibre material Fibre fineness Average fibre length ... 

Kind of fibre Fineness Weight of web Vertically to nonwoven... 

Krogerus B (1993) Dynamic flocculation studies on fibre fines and filler clay. Nordic Pulp Paper Res J 8 135... 

The thermo-insulating properties of lofty non-woven fabrics, which have been reported in several papers, depend on the nature of pore size and distribution in a fabric, which are a function of fibre fineness and material density. Jirsak et al. compared in a more comprehensive way the thermo-insulating properties of both perpendicular-laid and conventional cross-laid nonwoven fabrics. The total thermal resistance P of a textile fabric as a function of the actual thickness of the material ... 

Bubbles breaking on fibre web leaves behind solids (fibres, fines, pigments, pitch, etc.)... 

It is therefore convenient to use instead of the cross-sectional area a related quantity, linear density, which is defined as mass per unit length its SI unit is kgm" From the definition of linear density it follows that it is equal to the product of the average cross-sectional area (m ) and the density p (kgm ). Since the linear densities of fibres are usually around 10" -10 kgm it is much more convenient to use a tex unit (1 tex = 10 kgm = 1 gkm ), or its 0.1 submultiple, dtex. Information about other units and other systems used for designation of fibre fineness can be found elsewhere. 

Electrospun nanohbrous structure possess several attractive features, such as high porosity and interconnected open pore structure, submicron pore sizes, and a large surface area-to-volume ratio. These characteristics make them an ideal material candidate for removing sohd substances from air or hquid [6]. To demonstrate the filtration performance of electrospun nanohbre membrane, a thin coat of electrospun PAN nanohbres over a metal mesh has been shown to collect more than 95 % of PM2.5 (i.e. particulate matter in size of 2.5 pm) in a polluted city environment with 90 % transparency [323]. Filtration efficiency, which is closely associated with fibre fineness, is one of the most important concerns for the filter performance [6]. Molaeipour et al. [324] used ultrafine cellulose acetate nanofibres with different diameters to evaluate their filtration efficiencies for tar removal. It was found that... 

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