Modacryls

Modacrylic Modacrylic fibers Modacrylics Modane Modeling Modeling systems Mode-locked lasers Model rocket engines Models... 

Fig. 3. An aqueous dispersion polymerization process used in the manufacture of acrylic and modacrylic fibers.

Modacrylic—fiher-forming substance is any long-chain synthetic polymer composed of less than 85% hut at least 35% hy weight of acrylonitrile units. 2.5-3.0 G G G G G 1.30 180... 

Acrylonitrile is mainly used to produce acrylic fibers, resins, and elastomers. Copolymers of acrylonitrile with butadiene and styrene are the ABS resins and those with styrene are the styrene-acrylonitrile resins SAN that are important plastics. The 1998 U.S. production of acrylonitrile was approximately 3.1 billion pounds. Most of the production was used for ABS resins and acrylic and modacrylic fibers. Acrylonitrile is also a precursor for acrylic acid (by hydrolysis) and for adiponitrile (by an electrodimerization). 

Acrylic fibers are a major synthetic fiber class developed about the same time as polyesters. Modacrylic fibers are copolymers containing between 35-85% acrylonitrile. Acrylic fibers contain at least 85% acrylonitrile. Orion is an acrylic fiber developed by DuPont in 1949 Dynel is a modacrylic fiber developed by Union Carbide in 1951. 

Dynel, a modacrylic fiber, is produced by copolymerizing vinyl chloride with acrylonitrile. Solution spinning is also used where the polymer is dissolved in a solvent such as acetone. After the solvent is evaporated, the fibers are washed and subjected to stretching, which extends the fiber 4-10 times of the original length. 

The primary use of acrylonitrile is as the raw material for the manufacture of acrylic and modacrylic fibers. Other Major uses include the production of plastics (acrylonitrile-butadiene- styrene (ABS) and styrene-acrylonitrile (SAN), nitrile rubbers, nitrile barrier resins, adiponitrile and acrylamide (EPA 1984). 

Residual acrylonitrile monomer may also occur in commercially-made polymeric materials used in rugs and other products. Estimated levels include acrylic and modacrylic fibers (less than 1 mg acrylonitrile/kg polymeric material), acrylonitrile-based resins (15 to 50 mg/kg), and nitrile rubber and latex (0 to 750 mg/kg) (IARC 1979 Miller and Villaume 1978). It is possible that acrylonitrile may evaporate into air or leach into water from these products, but no data on this topic were located. 

IARC. 1979. Acrylonitrile, acrylic and modacrylic fibres, and acrylonitrile-butadiene-styrene and styrene-acrylonitrile copolymers. IARC monographs on the evaluation of the carcinogenic risk of... 

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] ... 

Some anthraquinone dyes with pendant cationic groups are used commercially on acrylic and modacrylic fibres [22]. Only two disclosed structures are included in the latest revision of the Colour Index, the dyes being the reddish blue Cl Basic Blue 47 (6.54) and the greenish blue Cl Basic Blue 22 (6.55). 

Acrylic fibers. Acrylic fibers are polymers of acrylonitrile and another chemical. When acrylonitrile is 85% or more of the polymer, the fiber is called acrylic. If there s more copolymer so the percentage of acrylonitrile decreases to 35-85%, the fiber is called modacrylic. Some of the popular monomers used as copolymers are methyl acrylate and methacrylate, acrylamide, vinyl acetate, vinylidene chloride, and vinyl chloride, Dynel is 40% acrylo and 60% vinyl chloride. 

It is difficult to find any definitive information that indicates ozone damage as extensive as that suggested in the mri report. The latter identified cotton, nylon, and rayon as particularly susceptible to ozone. The oxidation of cellulose fibers by ozone was the subject of a study in 1952 that showed that dry cotton was not seriously degraded by ambient ozone. In more recent studies, these conclusions were confirmed. The only information available on fibers other than cotton addressed the effect of ozone on modacrylic, acrylic. Nylon 66, and polyester fabrics.The results indicated minimal effects on these fibers. 

Uses Copolymerized with methyl acrylate, methyl methacrylate, vinyl acetate, vinyl chloride, or 1,1-dichloroethylene to produce acrylic and modacrylic fibers and high-strength fibers ABS (acrylonitrile-butadiene-styrene) and acrylonitrile-styrene copolymers nitrile rubber cyano-ethylation of cotton synthetic soil block (acrylonitrile polymerized in wood pulp) manufacture of adhesives organic synthesis grain fumigant pesticide monomer for a semi-conductive polymer that can be used similar to inorganic oxide catalysts in dehydrogenation of tert-butyl alcohol to isobutylene and water pharmaceuticals antioxidants dyes and surfactants. 

Uses Synthetic fibers and adhesives chemical intermediate in vinylidene fluoride synthesis production of poly(vinyl dichloroethylene) and LLl trichloroethane comonomer for food packaging, coating resins, and modacrylic fibers. 

Fibers with more than 85% acrylonitrile units are called acrylic fibers but those containing 35%-85% acrylonitrile units are referred to as modacrylic fibers. The remainder of the modacrylic fibers are derived from comonomers, such as vinyl chloride or vinylidene chloride, that are specifically added to improve flame resistance. 

Modacrylic Acrylonitrile units, 35%-85% Resilient, softenable at low temps., easy to dye, abrasion-resistant, quick drying, shape-retentive, resistant to acids, bases Simulated fur, scatter rugs, stuffed toys, paint rollers, carpets, hairpieces, wigs fleece fabrics Verel, Dynel... 

Elastine/Spandex Poly(vinyl chloride) Aramid Modacrylic Vinyal... 

Modacrylic staple fibers Polyamide resins Polyester thermoplastic Co-extruded film Polymelitimide Nylon-12 PVC PS... 

Acrylic and modacrylic fibers have a wool-like appearance and feel, and excellent resistance to heat, ultraviolet radiation, and chemicals [Bajaj and Kumari, 1987]. These fibers have replaced wool in many applications, such as socks, pullovers, sweaters, and craft yams. Other applications include tenting, awning fabric, and sandbags for rivershore stabilization. The use of acrylic and modacrylic fibers in carpets is low since these materials do not hold up well to recycling through hot-humid conditions. This also prevents its use in the easy-care garment market. 

An example of this type of a safer chemical is methacrylonitrile (1) compared with acrylonitrile (2) (Figure 1.1). Both compounds are a, 3-unsaturated aliphatic nitriles, and structurally very similar, but 2 causes cancer whereas 1 does not appear to do so. Among other applications, 2 is used in the production of acrylic and modacrylic fibers, elastomers, acrylonitrile-butadiene-styrene and styrene-acrylonitrile resins, nitrile rubbers, and gas barrier resins. In a study conducted by the US National Toxicology Program (NTP) in which 2 was administered orally to mice for 2 years, there was clear evidence that it caused cancer in the treated mice (in addition to causing other toxic effects), and is classified by the NTP as a probable human carcinogen [26]. 

Worldwide consumption of acrylonitrile increased 52% between 1976 and 1988, from 2500 to 3800 thousand tonnes per year. The trend in consumption over this time period is shown in Table 2 for the principal uses of acrylonitrile acrylic fibre, acrylonitrile-butadiene-styrene (ABS) resins, adiponitrile, nitrile rubbers, elastomers and styrene-acrylonitrile (SAN) resins. Since the 1960s, acrylic fibres have remained the major outlet for acrylonitrile production in the United States and especially in Japan and the Far East. Acrylic fibres always contain a comonomer. Fibres containing 85 wt% or more acrylonitrile are usually referred to as acrylics and fibres containing 35-85 wt% acrylonitrile are called modacrylics . Acrylic fibres are used primarily for the manufacture of apparel, including sweaters, fleece wear and sportswear, and home furnishings, including carpets, upholstery and draperies (Langvardt, 1985 Brazdil, 1991). 

Methyl acrylate is used in manufacture of acrylic and modacrylic fibres, amphoteric surfactants, leather finish resins, textile and paper coatings and plastic films (United States National Libraiy of Medicine, 1997). 

Acrylic and modacrylic fibers are sold mainly as staple and tow products with small amounts ofconltnunus filament liber sold in Europe and Japan. 

---