Polyamide yarns

Table II gives the crystallinity values for various kinds of polyamide yarns. In one case, the occurence of a relatively amorphous skin can be detected. There is also an example of the effect of an azimutal correction. Absolute crystallinity values do not agree well with X-ray based crystallinity values. Nevertheless, there is a general qualitative agreement in the difference between polyamide and polyester yarns (it is well known that crystallinity is generally higher for polyamide than for polyester commercial filaments).

Clear viscous aqueous solution. Highly effective size for filament polyamide yarns. SYNCOL F25 exhibits very high adhesion to polyamide fibres producing warps of high weaving efficiency at relatively low application levels. 

For level dyeing of filament or textured polyamide yarn, fabrics and carpets with acid dyestuffs. 

As a conductive textile electrode, Shieldex , an Ag-coated polyamide yarn produced by Statex Produktions Vertriebs GmbH (Bremen, Germany) represented... 

MECHANICAL AND THERMAL PROPERTIES OF AN AROMATIC POLYAMIDE YARN /HT-1 OR NOMEX/. 

Osawa M and Jinno M (1986) Production of totally aromatic polyamide yarn. Applicant Mitsui Toatsu Chemicals, Japan Patent 61,201,009. 

Again the standard RFL system is ideal for use with polyamide yarns and fabrics. With these fibres, however, it is necessary to use higher levels of VP latex than with rayon, a minimum of 80% VP latex being required to obtain the optimum levels of adhesion. This is illustrated in Table 9.3. 

Polyester yarns are generally much less reactive than the cellulosic or polyamide yarns, and so require additional treatments to achieve adequate levels of adhesion. 

The belts of radial tires contain fabric layers that lie diagonally to each other (at an angle of 20° up to 25°). The belt guarantees the stability of the tires. It consists mostly of steel fabrics because radial tires with a steel belt outmatch the textile belt tire. For some years, a layer of less-twisted polyamide yarns has been used above the belt. This so-called top layer decreases the danger of separation from the edge of the belt and increases the capacity at high speeds. 

We can manufacture fibers from a wide range of polymers. Polyamides, polyesters, and polypropylene can be woven or knitted into fabrics, ranging from those as coarse and strong as those used in back packs, luggage, and sails, to soft and highly flexible fabrics used in sweaters, shirts, and other apparel. Polymer filaments and yarns can be twisted or woven to make string, twine, cords, and ropes. 

EMS hybrid yarns or Schappe s preimpregnated yarns are a combination of reinforcing fibres (glass, aramid or carbon) and polyamide 12. 

Various 66 polyamide continuous yarns were also examined (referred to as, "type 2", "type 4" and "type 5") these are experimental yarns prepared in different conditions and supplied by RPT. 

Polyamide fibres can be dyed with both cold- and hot-dyeing reactive colours in a liquor containing 4 per cent of the weight of the goods of acetic acid 80 per cent. The load is entered at 40°C (104°F) and the temperature brought up to 95°C (203°F), after which dyeing is continued for 1 hour, or more, if necessary. The reaetive dyes are satisfactory on staple yarns where differences in the affinity of the polyamide fibre are randomized. In continuous filaments any irregularities in the yarn are not covered. 

Acid mordant and premetallized dyes can be applied to polyamides. They build up well into dark shades and the light- and wet-fastnesses are good. It must, however, be borne in mind that they are worse than other classes for emphasizing yarn variations. These dyes have no migrating properties once they have been taken up by the fibre and it is therefore most important to control conditions during dyeing in such a manner that the initial adsorption is uniform. 

Polyamide-6 (Nylon-6, Perlon) and polyamide-6.6 (Nylon-6.6) are the most well known polyamides. Polyamide-based filaments find wide spread applications as yarns for textile or industrial and carpet materials [70], However, nylon-based textiles are uncomfortable to wear and difficult to finish due to their hydrophobic character. This characteristic also leads to fouling of PA-based ultrafiltration membranes by proteins and other biomolecules which increases the energy demand for filtration and requires cleaning with aggressive chemicals or replacement [71-73], Consequently the enhancement of the hydrophilicity of nylon is a key requirement for many applications and can be achieved by using plasma treatment [74-76], As a promising alternative, enzymatic hydrophilization of PA requires less energy and is not restricted to planar surfaces. 

Blends of PA-66 with some aliphatic-aromatic polyamides of higher T such as poly (hexamethyl-ene isophthalamide) (PA-61) have been evaluated as hbers, in order to achieve improved modulus and heat resistance in PA-66 tire yarn and con-... 

For linear polyamides, the viscosity of dilute or moderately concentrated solution can be related closely to M . Thus, the molecular weight of polymer can be evaluated from i inh = ln reiA- This is usually measured at a concentration of 0.5 g of polymer in 100 ml of solvent, e.g., m-cresol. A typical value of T i h of nylon-6,6 is one forMn of about 15,000. Another method of characterization commonly used is to measure the relative viscosity (RV) of an 8.4% solution of polymer in 90% formic acid. Typical values of relative viscosity for nylon-6,6 are in the range of 30 to 70. An RV of 41 corresponds toMn of about 15,000, whereas an RV of 60 corresponds to about 19,000. Polymers in the lower range are used for textile yarns, and those in the higher range for industrial yarns. 

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