Modified fibres acrylic

Research into controlled-release antimicrobials continues with organo-silver compounds and silver zeolites, which are promising candidates for textile finishes. Silver ions, for example, incorporated in glass ceramic, have a very low toxicity profile and excellent heat stability. These principles are also used for fibre modification, an alternative to the antimicrobial finishes with high permanence. In recent years a variety of antimicrobial modified fibres have been developed, including polyester, nylon, polypropylene and acrylic types. An example of these fibre modifications is the incorporation of 0.5-2 % of organic nitro compounds... 

The thermal stability of composites containing natural fibres may also depend on the nature of the matrix. In the case of composites containing unsaturated polyester or unsaturated polyester modified with acrylic acid reinforced with jute fibres it was shown that the composites with modified polyester matrix were more resistant to temperature than the ones with unmodified polyester matrix. The reason for this enhanced thermal stability was the presence of acrylic acid as modifier [45]. 

Many brilliantly coloured and tinctorially strong basic dyes for silk and tannin-mordanted cotton were developed in the early decades of the synthetic dye industry. Most of these belonged to the acridine, azine, oxazine, triarylmethane, xanthene and related chemical classes their molecules are usually characterised by one delocalised positive charge. Thus in crystal violet (1.29) the cationic charge is shared between the three equivalent methylated p-amino nitrogen atoms. A few of these traditional basic dyes are still of some interest in the dyeing of acrylic fibres, notably as components of cheap mixture navies and blacks, but many modified basic dyes were introduced from the 1950s onwards for acrylic and modacrylic fibres, as well as for basic-dyeable variants of nylon and polyester [44] ... 

Manfredi, L. B., Rodriguez, E. S., Wladyka-Przybylak, M., and Vazquez, A. Thermal degradation and fire resistance of unsaturated polyester, modified acrylic resins and their composites with natural fibres, Polym. Degrad. Stabil. 2006, 91, 255-261. 

The most successful approach for flame-retarding acrylic fibres is to copolymerise halogen-containing monomers into the fibre. These modacrylic fibres have excellent permanent flame retardancy and acceptable fibre properties. Some problems including reproducibility of dyeing gave rise to their substitution by flame-retardant modified polyester, for example for curtain fabrics and other decorative textiles. 

Acrylics and modacrylics. Flame retarded acrylics find little application within the technical textile sector and they are usually so highly modified in terms of comonomer content that they are termed modacrylics. This latter group has been commercially available for 50 years or so but at present few manufacturers continue to produce them. The preferred comonomer is vinylidene choride and to enhance the flame retardant activity of the chlorine present, antimony III oxide (ATO) is included, although this may reduce the lustre of the fibres and resulting fabrics. Modacrylic fibres, like acrylic... 

Electrical conductivity measurements have been reported on a wide range of polymers including carbon nanofibre reinforced HOPE [52], carbon black filled LDPE-ethylene methyl acrylate composites [28], carbon black filled HDPE [53], carbon black reinforced PP [27], talc filled PP [54], copper particle modified epoxy resins [55], epoxy and epoxy-haematite nanorod composites [56], polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) blends [57], polyacrylonitrile based carbon fibre/PC composites [58], PC/MnCli composite films [59], titanocene polyester derivatives of terephthalic acid [60], lithium trifluoromethane sulfonamide doped PS-block-polyethylene oxide (PEO) copolymers [61], boron containing PVA derived ceramic organic semiconductors [62], sodium lanthanum tetrafluoride complexed with PEO [63], PC, acrylonitrile butadiene [64], blends of polyethylene dioxythiophene/ polystyrene sulfonate, PVC and PEO [65], EVA copolymer/carbon fibre conductive composites [66], carbon nanofibre modified thermotropic liquid crystalline polymers [67], PPY [68], PPY/PP/montmorillonite composites [69], carbon fibre reinforced PDMS-PPY composites [29], PANI [70], epoxy resin/PANI dodecylbenzene sulfonic acid blends [71], PANI/PA 6,6 composites [72], carbon fibre EVA composites [66], HDPE carbon fibre nanocomposites [52] and PPS [73]. 

Acid dyes Reactive dyes Basic Direct dyes Mordant dyes Disperse dyes Vat dyes Solvent dyes Fluorescent brightners Other dye classes Nylon, sUk, wool, paper, inks and leather Cotton, wool, sUk and nylon Paper, polyacrylonitrile, modified nylon, polyester and inks Cotton, rayon, paper, leather and nylon Wool, leather and anodised altiminirun Polyester, polyamide, acetate, acrylic and plastics Cotton, rayon and wool Plastics, gasoline, varnishes, lacquers, stains, inks, fats, oils and waxes Soaps and detergents, aU fibres, oils, paints and plastics Food, drugs and cosmetics, electrography, direct and thermal transfer printing... 

The capacity of hydrophobic fibres to retain water can be enhanced substantially by modifying the fibre geometry. Thus, an acrylic fibre with a porous core covered by a thin channelled sheath can retain as much as 30% water. " The use of fine profiled fibres affects the area and shape of the channels between the assembled fibres, and this improves the moisture transport through a fabric... 

The use of a polymer modified cement matrix reinforced with E glass fibres was developed by Bjjen and Jacobs [99-104], using a special acrylic polymer (Forton) which was developed for that purpose. In the production of this composite, the tiny polymer latex particles ( 0.1 p.m in diameter) infiltrate and fill the spaces between the filaments in the strand and eventually coalesce into a film. Thus they can provide a protective effect, both to reduce the chemical attack, and to reduce the extent of the microstructural mechanism, by eliminating the growth of dense and rigid hydration products around the filaments. The coalescence of... 

Figure 12.32 Load-deflection curves in bending of polymer modified matrices (broken lines) and fibre-reinforced polymer modified cements (full lines) made of Portland cement (control) and cements modified with 18% saran (SA), styrene-butadiene (SB) and acrylic (AC) latex (after Bentur [146]).

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