Dyeability

Different degrees of dyeability of staple fibers and filaments for textile applications seriously affect the constancy of product quality. This phenomenon has become more or less a matter of industrial production experience. Only a few 

Apart from a certain influence of mechanical properties, the manufacturing of films is mainly focused on the transparency and brilliancy (gloss) of the film. Agglomerations or other imperfections caused by the polymer, including solid 

In contrast to fiber-forming technologies, the film process requires a comparatively reduced IV due to processing reasons, for example, the pressure along the die and therefore the evenness of thickness as well as the generation of structure, particularly with respect to crystallinity, will need to be considered. As usual, a compromise between intrinsic physical properties and processing has to be found. 

21 Stacey, Hatranote, 14 (HATRA) Woolard, Control (Shirley institute, 1972). 

27 Holfeld, AATCC Symposium Knit Shrinkage Cause, Effect and Control , (Oct. 1973) 37. 

30 Tech. Inf. Manual LF/1/3, Terylene, Fibre Division, Imperial Chemical Industries Ltd. 

32 Nunn (Ed.), The Dyeing of S3mthetic Polymer and Acetate Fibres, Dyers Co. Pub. Trust, (1979) pl77. 

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Dyeability Dye aggregation Dye carrier applications Dye carriers Dye combinations Dye developer Dye fixative Dyeing... 

Anfarbbarkeit, /. colorability, dyeability. anf lrben, v.t. color, dye. paint, tint, tinge ... 

A long-standing goal in polyolefins is the synthesis of polymers bearing polar functional groups such as acrylate, esters, or vinyl ethers, etc [24,40]. These copolymers might endow polyolefins with useful properties such as adhesiveness, dyeability, paintability, and print-ibility. Advances have recently been made in polymerizing polar monomers with cationic metallocene catalysts... 

Electron beam-initiated modification of polymers is a relatively new technique with certain advantages over conventional processes. Absence of catalyst residue, complete control of the temperature, a solvent-free system, and a source of an enormous amount of radicals and ions are some of the reasons why this technique has gained commercial importance in recent years. The modification of polyethylene (PE) for heat-shrinkable products using this technique has been recently reported [30,31]. Such modification is expected to alter the surface properties of PE and lead to improved adhesion and dyeability. 

Melt spinning polyesters is preferred to solution spinning because of its lower cost. Due to the hydrophobic nature of the fiber, sulfonated terephthalic acid may be used as a comonomer to provide anionic sites for cationic dyes. Small amounts of aliphatic diacids such as adipic acid may also be used to increase the dyeability of the fibers by disturbing the fiber s crystallinity. 

The interest in this problem arises from the desire to eliminate some drawbacks typical of PAN and the materials obtained from it enhanced stiffness, poor dyeability, electrifiability, combustibility, etc., as well as from a wide range of possibilities in producing, based on PAN, new readily available materials with specific technologically valuable properties. 

As it is known at present in all countries producing PAN fibres, AN copolymers containing 5—10% of a second monomer are used to increase the elasticity and, in most cases, a third monomer (1-25%) is added to improve the dyeability. 

When modified fibres of type 5 are treated with hydroxylamine, oxime groups are also easily formed. The interaction with a protein affords a sandwich polymer22. Fibres modified in this way have enhances dyeability. When copolymer fibres are treated with diamine solutions or in acid medium with Fe+3 salts, intermolecular chemical bonds are formed, which results in a considerable increase of the temperature of zero strength and of the heat resistance of fibres. These conversions are shown in Scheme 2. 

A surface is that part of an object which is in direct contact with its environment and hence, is most affected by it. The surface properties of solid organic polymers have a strong impact on many, if not most, of their apphcations. The properties and structure of these surfaces are, therefore, of utmost importance. The chemical stmcture and thermodynamic state of polymer surfaces are important factors that determine many of their practical characteristics. Examples of properties affected by polymer surface stmcture include adhesion, wettability, friction, coatability, permeability, dyeabil-ity, gloss, corrosion, surface electrostatic charging, cellular recognition, and biocompatibility. Interfacial characteristics of polymer systems control the domain size and the stability of polymer-polymer dispersions, adhesive strength of laminates and composites, cohesive strength of polymer blends, mechanical properties of adhesive joints, etc. 

One of the earliest fibre pretreatments for improving the dyeability of cotton is of course mercerisation (section 10.5.4). However, more recent research interest in this area has been generated by environmental concerns about reactive dyeing, aiming to enhance substantivity for the modified fibre so that higher absorption and fixation are obtained. This results in less dye (hydrolysed or still active) in the effluent. A further objective is to minimise the usage of electrolyte in the application process. This area has been thoroughly reviewed [392,393]. 

Esterification Inorganic or organic acids Improved dyeability... 

Amination Epoxides in alkali, including ethylene oxide, propylene oxide, glycidol (2,3-epoxypropan-l-ol). Scheme 10.58 shows glycidyltrimethylammonium chloride Glycidyltrimethylammonium chloride marketed to enhance dyeability with direct and reactive dyes... 

Amination A/-Methylolacrylamide in presence of Lewis acid catalyst. Further modifications possible by addition to double bond (Scheme 10.61) Amines with durable press resins Improved dyeability with dichlorotriazine dyes at pH 5 without salt, giving 99% fixation Some improvements in dyeability, especially with direct dyes, but light fastness can be a problem... 

Enhanced dyeability with anionic and reactive dyes, the latter applied under neutral or slightly acidic conditions. Reduced light fastness and marked dulling with some dyes... 

Recently, nitrilases have been applied to polymer modification, specifically to the modification of polyacrylonitrile (PAN). Nearly 3 x 106 tons of PAN are produced per annum and used in the textile industry. However, there is a great need to improve moisture uptake, dyeability with ionic dyes, and feel of this acrylic fiber. The cyano moieties of PAN have been successfully modified to carboxylates with the commercial Cyanovacta nitrilase, thus enhancing the aforementioned properties of PAN [98]. Nitrilase action on the acrylic fabric was improved... 

Cellulose phosphate(s), 5 401 8 29 20 459 flame resistant, 8 27 paper, 5 408 solubility of, 5 402 Cellulose propionate manufacture of, 5 418 moisture properties, 5 416t Cellulose propionate valerate, 5 421 Cellulose propionate isobutyrate, 5 421 Cellulose substrates, dyeability of, 9 482-483... 

Dyazide, molecular formula and structure, 5 165t Dyeability... 

Nylon. See also Nylons advanced material, 1 693 applications for, 19 765-766 dyeability of, 19 758-760... 

Polyamide fibers, 19 739-772. See also Synthetic polyamides applications for, 19 765-766 chemical properties of, 19 745-747 cross-section shape of, 19 756 dyeability of, 19 758-760 early reactive dyes for, 9 468-470 electrical properties of, 19 745 manufacture of, 19 748-749 modified nylon-6 and nylon-6,6, 19 760-764... 

Disulphonated dyes of relative molecular mass (Mr) about 400-600 that are somewhat sensitive to dyeability differences in the substrate and show the lowest wet fastness of all dye classes used on wool... 

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