Fibres curling

Fibre curling can be eliminated by beat treatment under tension near the mp, and the resulting fibres have a tensile strength of 3.S X 10 psi (1 psi = 689SNm ) and an elastic modulus of SO x 1( psi at a density of 2.35gcm the form was... 

The mechanical properties of nonwoven fabrics are determined by the properties of fabric constituents and the structural arrangement of these components. Among the important aspects of fibre morphology are fibre orientation, fibre curl and thickness. Their changes can affect the mechanical behaviour and failure mechanisms. These parameters can also be varied and controlled more easily during manufacture to improve fabric design and performance (Adanur Liao, 1999). 

A product used in upholstery and as a resilient packaging material. It is made by spraying a loose mat of curled animal hair with latex and applying heat to vulcanise the rubber. The resilience of the product comes from the fibres, the junction points of which are anchored by the rubber. 

Layers of type (c) only. The pure Mg layer occurs in chrysotile, (0H)4Mg3Si20s, in which the structural unit is a kaolin-like layer of this composition, instead of (0H)4Al2Si205 as in Fig. 23.16. Since the dimensions of the brucite (Mg(OH)2) part of the composite layer do not exactly match those of the Si205 sheet, the layer curls up, the larger (brucite) portion being on the outside. The fibres are built of curled ribbons forming cylinders several thousand A long with a dozen or so layers in their walls and overall diameters of several hundred the detailed structures of chrysotiles are still not known, nor is the... 

We referred earlier to the silylation of silicates to give trimethylsilyl derivatives corresponding to the Si—0—Si systems in the original minerals. A development of this idea is to treat chrysotile with a mixture of HCl and ClSi(CH3)3 when the Mg and OH ions are stripped off the outside of the layer and replaced by -OSi(CH3)3, giving a gel which on treatment with water forms a fibrous mass of ribbons. When dry these curl up to form fibres similar in shape to those of the original chrysotile. ... 

After refining the pulps go to latency tanks (2-4% consistency at about 80°C) where they are held and slightly agitated for several minutes. This improves pulp properties by slowly relieving internal stresses and removing the curled conformation of the fibres that resulted from lignin stiffening, when the pulp left the refiner. 

Natural fibres, such as wool or cotton, have a curled or irr ular shape. Yams and fabrics made from these fibres are bulky and have a high thermal insulation and a pleasant grip and appearance. Many methods have been developed to give synthetic yams and fibres simUar properties. This is called texturisation. In texturisation processes unannealed yams or fibres are usually deformed by twisting, stuffing or knitting. They are then heat-set in the deformed state, which makes the deformation more or less permanent Most of those processes can be applied to split fibres but we shall only deal with techniques in which orientation effects play an important role. 

One of those methods is sometimes applied to spun yams from staple fibres. Instead of a single type of fibre, a blend of two or more fibres is used which differ in shrinkage properties. The yams are then heated in the wet or dry state, depending on the type of fibres. Part of the fibres shrink and the other fibres must form loops or curls, resulting in an increased bulkiness of the yam. Sometimes fibres are blended from polymers which differ in melting point the temperature is so selected that only the lower melting fibres will show an appreciable shrinkage. It is also possible to use... 

Pulp and fibre properties following HC and LC refining, along with those of unrefined pulp, are shown in Table 13.5. HC refining has practically no effect on fibre properties, other than fibre length, which seems to be shortened due to curling. After a relatively low-energy... 

Reactions in which radioactivity has been incorporated into a precipitable macromolecule [135]. This technique involves collecting the precipitate on filter paper discs, although glass fibre discs are claimed to be an improvement [136—137] since they can hold more liquid than cellulose, do not curl on drying, and give much improved counting efficiencies for tritium. 

PDI has also been used for treatment of wool [179] and hair fibres [180]. King and Brockway [179] showed that PDI was able to restore part of the original properties on aged or harshly treated wool. The same enzyme was used by Brockway [180] to perform a curling, waving or straightening treatment safely under mild condition. 

J.W.S. Hearle, V. Ozsanlav, Nonwoven fabric studies. Part 5 Studies of adhesive-bonded nonwoven fabrics. Part 3 The determination of fibre orientation and curl, J Text Inst 70 (1979) 487-497. 

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