Polymeric dyes polyamides

It is difficult for dye solutions in water to penetrate synthetic fibers such as polyester, cellulose triacetate, polyamides, and polyacryUcs which are somewhat hydrophobic. The rate of water imbibition differs with each fiber as shown in Table 1 as compared to viscose (see Fibers, regenerated CELLULOSics), which imbibes water at the rate of 100% (1). The low imbibition rate is attributed to the high T obtained when the polymeric fibers are drawn. During this drawing operation the polymer chains become highly oriented and tightly packed, forming a stmcture practically free of voids. 

Amino-1,2,4-thiadiazoles79 and their 3-alkoxy-, 3-alkylmercapto-, and 3-dialkylamino derivatives84 have been claimed to be useful intermediates in the manufacture of dyes,84 pharmaceuticals,84 and materials valuable in pest control.79 Mono-azo dyes derived from diazotized 5-amino-l,2,4-thiadiazoles and coupling components of the benzene series are especially suitable for dyeing polymeric materials such as acetate rayon, polyamides, polyurethanes, polyesters, and... 

Chemical Composition. In polyamide 6 (PA 6, polymerization product of e-caprolactam) and polyamide 66 (PA 66, adipic acid polymerized with hexamethylene-diamine) one chain end consists of an amino group, which can be present in the free state or in the acylated form. Amino groups are of special importance for dyeing because they form ammonium groups in an acidic dyebath by addition of protons. The lower dye uptake in comparison to wool is caused by the comparatively low number of amino groups. The depth of color achieved on PA 6 is somewhat less than that on PA 66. 

Pure acrylonitrile may polymerize at room temperature to polyacrylonitrile (PAN), a compound that, unlike polyamides and polyesters, does not melt at elevated temperatures but only softens and finally discolors and decomposes. Nor is it soluble in inexpensive low-boiling organic solvents. Because fibers made from it resist the dyeing operations commonly used in the textile industry, the usual practice is to modify it by copolymerization with other monomers, for example, vinyl acetate, styrene, acrylic esters, acrylamide, or vinyl pyridine in amounts up to 15 percent of the total weight (beyond which the final product may not be termed an acrylic fiber). The choice of modifier depends on the characteristics that a given manufacturer considers important in a fiber, the availability and cost of the raw materials in the manufacturer s particular area of production, and the patent situation. 

One of the first non-formaldehyde fluorescent dye carrier systems for polyolefins was based on the reaction of polyfunctional amines with polyfunctional carboxylic acids to form relatively short chain polyamides [5].These linear thermoplastic resins showed good solubility and friability making them suitable for the incorporation of dyes, which offered increased protection from thermal and UV degradation. This fluorescent resin showed a dramatic increase in color retention upwards of 288°C, even after a 10 minute hold period at this temperature. Due to its non-ide-alized polymeric nature, the polyamide chemistry suffered from preferential plating out or migration of polar oligomeric species not incorporated into the polymer chains. 

Cotton is pure cellulose. Nylon is a polyamide and made by polymerizing adipic acid and hexamethylenediamine. The nylon polymer chain can be prepared with one acid and one amine group at the termini, or with both acids or both amines. Except for these terminal groups, there are no polar centers in nylon and consequently it is difficult to dye. Similarly Dacron, a polyester made by polymerizing ethylene glycol and terephthalic... 

Furthermore, cationic dyes 179 of the diazahemicyanine class are derived from indolizines. This invention related to water-soluble azo dyestuffs is useful for the colorations of synthetic polymeric materials particularly polymers and copolymers of acrylnitrile and dicyanoethylene as well as modified polyesters and polyamides (81GBP2075540, Scheme 64). 

Nylon. Nylon is a trade name for high-molecular weight polyamides that result from condensation polymerization of dibasic acids and diamines, or from u)-amino acids. Nylon can be extruded from a melt as monofilaments, or spun from a solution of formic acid, HCOOH, and phenol, C5H5OH. The resulting fibers have a low density, are elastic and lustrous, and mass for mass are stronger than steel. However, they are also low melting and difficult to dye. 

The two major classes of dyes used in melt coloring polymeric materials are the anthraquinones and the perinones. Between the two they offer the colorist a complete range of colors from yellow to violet - and many are suitable for use in polyamide blends and alloys. 

Polar, Uncharged Surfaces. Polar, uncharged surfaces include many of the synthetic polymeric materials such as polyesters, polyamides, and polyacrylates, as well as many natural materials such as cotton and silk. As a result of their surface makeup, the mechanism and extent of adsorption onto such materials is of great potential technological importance, particularly in terms of dyeing processes, waterproofing, and detergency. The mechanism of adsorption onto these surfaces can be much more complex than that of the nonpolar case discussed above, since such factors as orientation will be determined by a balance of several forces. 

These poly(amide-imide) materials were extensively studied in the 1980s in various aspects (e.g. synthesis and preparation of blends with other polymeric materials), [2, 88-96] demonstrating the increasing interest in these materials. More recently, water soluble polyamides and poly(amide-imide)s [97] as well as polyhydroxyimides [98] structurally analogous to those described in Fig. 4.18 have been reported. Additionally, photoactive polymers were prepared by the condensation of a maleopimaric adduct with azo-dye type diamines [99]. The levopimaric... 

Azidoformates have also been applied to polymeric substrates. Polymeric and non-polymeric compounds, p-RC6H4NEt(CH2)20CON3, useful as azo dyes or oil-, laundry-, and waterproofing agents for polyamide and polyester fibres, have been manufactured by treatment of a variety of chloroformates (prepared in situ with phosgene) with sodium azide [284]. 

At the time, Schlack knew the paper of Carothers and Ber-chet [7] only from an abstract, and he did not know their statement about their failure to polymerize caprolactam [s]. In his disappointment he first experimented with polyesters, but when he recognized their low dye affinity, he started again with polyamides. Schlack described how his invention came about with the following words [s] (Fig. 1) ... 

Swierenga and co-workers [79,80] in two articles described in detail their development of the calibration model used for PET measurements. Van Wijk et al. [72] summarized from their work that Raman spectroscopy can be used for determining the dye uptake or measuring one or more structural parameters or mechanical properties of polymeric fibers. Based on the results of their work, the authors stated that Raman spectroscopy was useful for studying melt-spinning thermoplastics, such as polyester, polyamide, polyolefins, and alternating copolymers of carbon monoxide and olefins so-called polyketones and, in addition, for polymers which are spun from solution such as cellulose, aromatic polyamides, polyketones, aromatic polyesters, and polyolefins. 

Inorganic pigment dispersant— photographic films Emulsifier—latex polymerization Ag halide emulsion stabilizer Thickeners, emulsifiers Cellulose nitrate latex stabilizer Inorganic pigments dispersant— photocopying Textile finishes dispersant Dispersant, thickeners polyamide dyes... 

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