Nylon fibres

Other reinforcing fibres, of less commercial importance, include asbestos, boron, and nylon fibres. 

This has been used in the past with both reinforced thermosets and thermoplastics, offering good rigidity, chemical resistance, and particularly fire resistance. Its use has, of course, ceased following discoveries of the health hazards associated with asbestos fibre. It may, however, he encountered in recovery of old mouldings, and advice should be sought immediately on the precautions necessary in handling it. 

This is of very high cost and is used with epoxy resins in specialized aerospace applications. 

This may be used with epoxy resins, for high impact, abrasion resistance, and chemical resistance. In moulding compounds with thermoplastics matrices it has very widespread use. 

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Also, in being a plastic, the surface of the nylon fibre is smooth,... 

The polyesters made by Carothers and his team proved a dead end in terms of commercial development for the time being, since the majority of them had melting points too low for practical utility, and there were also problems with low hydrolytic stability. Carothers turned to other classes of polymer, including, in 1934, polyamides, which he had previously briefly explored with Hill without any success. This work led to nylon fibres - first with Coffman, to nylon 9, then with Peterson, to nylon 5,10, and then, early in 1935, with Berchet, to nylon 6,6 [17],... 

When nylon is made in industry, it forms as a solid which is melted and forced through small holes (Figure 15.19). The long filaments cool and solid nylon fibres are produced which are stretched to align the polymer molecules and then dried. The resulting yarn can be woven into fabric to make shirts, ties, sheets and parachutes or turned into ropes or racket strings for tennis and badminton rackets. The annual worldwide production of nylon is expected to reach 6 million tonnes by 2015. 

Figure 15.19 Nylon fibre is formed by forcing molten plastic through hundreds of tiny holes.

Infusion Device Flow Rate. The example given in Table II shows that the flow rate with 4 aligned nylon fibre flow moderators in series is essentially constant up to 200 mL of... 

The infusion device described in this report can be fabricated in a few hours with materials usually available in a laboratory. For high flow, the aligned nylon fibre flow moderator can be used. When microvolume delivery is required, the use of the hollow fibre flow moderator can be considered. As for the infusion enclosures, the transparent material was specially chosen to allow visualization of the internal contents of the drug solution bag, which is always inspected at regualr intervals during use for the presence of particulate suspension or air bubbles that may develop and be harmful. 

FIG. 19.14 Structure model of (A) nylon fibres (B) PETP fibres (fibre axis vertical) as suggested by Prevorsek and Kwon (1976). 

The condensation products of aromatic sulfonic acids are used for dyeing and printings on nylon fibres, especially for the after treatment of carpets, to improve their wet fasmess by up to about two ratings. Their common name is syntan, derived from synthetic tannin . Figure 13.3 shows typical structures of syntans... 

Peracetic acid is particularly suitable for bleaching of nylon because this can be applied in a liquor which pH is virtually neutral and hence there is no danger of loss of strength of nylon fibre. The bath is set with pre-dissolved chemicals containing... 

Stenters are widely used for stretching, drying, heat-setting and finishing of fabrics (Fig. 8-3). Woven and knitted fabrics of polyester and nylon fibres and... 

This must place some doubt on results of fluorescent brightening agent concentrations determined in this way. A similar technique is also used to determine fluorescent brightening agents on nylon and acetate fibres [55]. A m-cresol-metha-nol mixture is used as solvent for nylon fibres and DMF for the acetate fibres. Extraction with a DMF-water mixture is recommended for cellulosic fibres. 16.13.3 Instrumental assessment... 

Wool or cellulose residues in blends with nylon The nylon fibres are dissolved out by treating the sample two to three times with concentrated fonnic acid for 15 min each time at room temperature. The sample is then thoroughly rinsed with concentrated formic acid, hot water, diluted ammonia and cold water and then dried. 

The nylon fibres PA 6 and PA 6.6 show the typical crenellation of the fibre surface in Frott61 reagent after maximally 5 min at room temperature. In the weaker Frott II reagent this reaction only occurs with PA 6 (see Table 8.1). Further differentiation is by determination of melting point (PA 6 = 215 °C, PA 6.6 = 255 °C, PET also at 255 °C). 

The chemistry of protein fibres, especially that of wool, is more complex than that of most other types of fibre. The amide groups which link the repeat units are also to be found in nylon fibres. Amides can be cleaved hydrolytically by strong acids and bases. However, the inter- and intramolecular bonds in wool are particularly numerous. There are hydrogen and disulphide bonds, salt links and hydrophobic attraction. All of these bonds are important for understanding chemical damage to wool and the possibilities for its detection. 

Table 8.14 Extent of damage and staining of acid-damaged nylon fibres with Rhodamine 6 ...

According to the literature (see section S087 there) damage due to mineral acids can easily be recognized under the microscope by means of the irreversible swelling of the nylon fibres. Acid residues can also be detected microscopically by embedding the sample in 0.1% Methyl Orange solution (typical needle formation, see Section 8.5.2). 

This is described in more detail in Table 8.15 and is shown in Table 8.16 in a review together with other methods for detecting damage to nylon fibres. The conclusions which can be drawn from these microscopic methods are unfortunately... 

Table 8.15 Damage to nylon fibres and Frotte reaction with modified zinc chloride-iodine reagent, according to Bubser and Modlich ...

Table 8.16 Review of detection methods for damage to nylon fibres ...

In the production of nylon fibres, especially nylon 6, oligomers can also be formed. They are soluble in water, as is also the monomer caprolactam, and thus they do not... 

Acids elastane fibres are stable to dilute mineral and organic acids at room temperature. At higher concentrations and higher temperatures damage occurs including dissolution. The structural relationship to nylon fibres becomes apparent here, as it also does in respect to dyeing behaviour. 

When bonding compounded rubber to fabric, for the manufacture of fabric reinforced expansion joints in the chemical plant piping systems, mechanical anchoring between cotton/Nylon/fibre and compounded rubber should be sufficient to ensure good adhesion. Synthetic fibres require treatment with chemical coatings to secure maximum adhesion and bond [8, 9]. 

Plastics and Fibres - polystyrenes, polyurethanes, engineering plastics, nylon fibres and chemicals, polyolefins ... 

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