Spin of polyamide

Giza, E., Ito, H., Kikutani, T., Okui, N. (2000a), Fiber structure formation in high-speed melt spinning of polyamide 6/clay hybrid nanocomposites , J Macromol Sci - Phys, 39 B (4), 545-559. 

Hollow-fiber permeators, 26 22 Hollow fibers, 13 389-390 cellulose ester, 26 19 cellulosic, 26 18-20 ion-exchange, 26 15 mechanical considerations and dimensions for, 26 5-7 natural polymer, 26 23 polyacrylonitrile, 26 23 polyamide, 26 21-22 post-treatment of, 26 13-14 preparation of, 26 3 production of, 19 757 with sorbent walls, 26 26 technology of, 26 27 wet spinning of, 25 816, 817-818 Hollow-fiber spinning processes, 26 7-12 Hollow fiber spinning technology,... 

This pigment is a special-purpose product for the spin dyeing of polyamide. 

The pigment has recently been introduced to the market. It is a specialty product for the spin dyeing of polyamide. P.Y.192 provides somewhat dull reddish yellow shades. 1/3 SD colorations with and without TiOz are thermally stable up to 300°C. Even samples which are formulated at very low pigment concentrations completely maintain their color. The pigment offers excellent textile fastnesses, such as resistance to dry cleaning and dry heat at 200°C (Sec. 1.6.2.4). Besides,... 

The simplest procedure for grafting copolymerization, in terms of number of components in the reaction medium, is a bulk polymerization of the monomer in mixture with the molten polyamide. This has been claimed in an earlier patent (2), related to improvements in dyeability and hydrophylic properties of the resulting yam, obtained by melt spinning of the product of reaction with monomers such as 2,5-dichloro styrene, lauryl methacrylate, N-vinyl pyrrolidone, and N-vinyl carbazole. 

Information on physical parameters of the molecular structure of polyamide fibers are usually obtained by x-ray diffraction methods, electron and light microscopies, infrared spectroscopy, thermal analyses such as differential thermal analysis, differential scanning calorimetry, and thermomechanical analysis, electron spin resonance, and nuclear magnetic resonance (NMR) spectroscopy. X-ray diffraction provides detailed information on the molecular and fine structures of polyamide fibers. Although the diffraction patterns of polyamide fibers show wide variation, they exhibit usually three distinct regions ... 

Conio et al. studied the fiber formation of PpBA from an organic solvent, viz. JV,JV -dimethylacetamide containing 3% LiCl, but in these experiments an air gap was hardly used [86]. This may be the reason that they arrived at somewhat different conclusions concerning the spinning of para-aromatic polyamide solutions. 

Polycondensation of p-phenylenediamine with terephthaloyl dichloride produces aromatic polyamides, which display liquid-crystal characteristics. The spinning of these polymers from hexamethylphosphoramide or sulfuric acid solution yields high-value aramid fibers (Kevlar Du Pont), Twaron Akzo) which are distinguished by their high temperature resistance (see Chapter 7.3.1). 

Fig. 2.26 An example of NMR used to probe local environment of a polymer in a blend/ N CPMAS (cross-polarization, magic angle spinning) NMR spectra of polyamide-6 in a blend with polyketone. PA-6 in a PK/PA 6 4 blend (a) shows primarily (70 %) its a-crystal phase, whereas in its pure form (b) PA-6 shows a 60 % y and 40 % a crystal (Data from Asano, Chap. 5 in Cheng et al. 2011)...

Aramids The term aramid is used to describe aromatic and partially aromatic polyamides, which constitute a class of materials that are analogous to the aliphatic nylons . The fully aromatic polymers in this category are linear, but not thermoplastic, as they decompose before they flow sufficiently to allow shaping. However, wet spinning of fibres is possible and such materials have many technical applications besides being used as reinforcement. 

Mini-fibers have also been observed by Liang et al. [159] on melt spinning polypropylene/polyamide blends. The diameters of the dispersed polyamide 6 phase mini-fibers are tens of microns and more. This is clearly due to the large interfadal tension in this system (polypropylene/polyamide 6) as compared to polyethylene/ polystyrene blends of Min et al. (Table 1.1). 

During the melt spinning of fibers such as polyamides, polyesters, and polypropylenes, the extruder pumps the melt or slurry through a spinneret die and into a containment box where the melt is cooled. The fiber is then drawn and wound on a bobbin. The process produces high levels of uniaxial orientation and facilitates crystallization of the fibers. 

All polyamide and polyester fibres owe their excellent mechanical properties to orientation resulting from drawing, just after spinning, at temperatures slightly above glass transition. The modulus of polyamide 6,6 is increased from 2 GPa after spinning to 6 GPa after drawing. 

---