Vinylidene chloride-acrylonitrile copolymers

Copolymers of vinylidene chloride with 5-50% acrylonitrile were investigated by IG Farben during World War II and found to be promising for cast films. Early patents by ICC and Dow indicated that the copolymers were rigid, transparent and with a high impact strength. 

Of commercial barrier polymers, only the ethylene-vinyl alcohol (EVOH) copolymers (see Chapter 14) show greater resistemce to gas permeability. However, the EVOH materials exhibit much higher levels of moisture absorption. 

In 1962 Courtaulds announced a flame-resisting fibre BHS said to be a 50 50 vinylidene chloride-acrylonitrile copolymer. This product has subsequently been renamed Teklan . 

A number of other copolymers with vinylidene chloride as the major component have been marketed. Prominent in the patent literature are methyl methacrylate, methyl acrylate and ethyl acrylate. 

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By copolymerising the vinylidene chloride with about 10-15% of vinyl chloride, processable polymers may be obtained which are used in the manufacture of filaments and films. These copolymers have been marketed by the Dow Company since 1940 under the trade name Saran. Vinylidene chloride-acrylonitrile copolymers for use as coatings of low moisture permeability are also marketed (Saran, Viclan). Vinylidene chloride-vinyl chloride copolymers in which the vinylidene chloride is the minor component (2-20%) were mentioned in Chapter 12. 

Inverse gas chromatography, IGC, has been used to study water sorption of two poly (vinylidene chloride-vinyl chloride) and poly (vinylidene chloride-acrylonitrile) copolymers, at temperatures between 20 and 50°C and low water uptakes. It was found that the specific retention volume of water increases with decreasing amount of water injected, increases dramatically with decreasing temperature and strongly depends on the type of copolymer. Thermodynamic parameters of sorption namely free energy, entropy, enthalpy of sorption and activity coefficient were calculated. 

In this paper, the water sorption of two commercially available vinylidene chloride copolymers is studied using IGC at low probe concentrations. The copolymers are a poly (vinylidene chloride-vinyl chloride) copolymer (Saran B) and a poly (vinylidene chloride-acrylonitrile) copolymer (Saran F). These copolymers are extensively used in the form of films, coatings, and film laminates in various industrial applications (for example, packaging of foods and pharmaceuticals) where their diffusion characteristics are of prime importance. 

Vinyl or vinylidene chloride/acrylonitrile copolymers Chlorosulphonated polyethylene, vulcanised chloroprene, chlorinated butyl rubber... 

The compositional analysis of a copolymer can be achieved by several methods other than NMR spectroscopy, such as elemental analysis, infrared and ultraviolet spectroscopies, and pyrolysis-gas chromatography. However, NMR spectroscopy has several advantages it does not need calibration if the operation conditions are properly set, and it can distinguish impurities easily. Quantitative aspects of compositional analysis by H and 13C NMR have been discussed for styrene-MMA copolymer12 and vinylidene chloride-acrylonitrile copolymer,13 respectively. 

Since cellophane cannot melt, it is not heat-sealable. The many hydroxyl groups that it contains make it sensitive to water. It will not dissolve, but its properties can change markedly on exposure to moisture. For both these reasons, cellophane used in packaging is generally coated. Common types of coatings include vinylidene chloride-acrylonitrile copolymers, polyolefins, and mixtures of cellulose nitrate, wax, and resin. It may also have plasticizers added to improve its flexibility. 

Vinylidene chloride-vinyl chloride copolymers are used in the manufacture of filaments. The filaments have high toughness, flexibility, durability, and chemical resistance. They find use in car upholstery, deckchair fabrics, decorative radio grilles, doll hair, filter presses, and other applications. A flame-resisting fiber said to be a 50 50 vinylidene chloride-acrylonitrile copolymer is marketed by Courtaulds with the name Teklan. 

Diofan BASF Vinyl chloride—vinylidene chloride-acrylonitrile copolymers... 

Poly (vinylidene chloride-co-acrylonitrile). See Vinylidene chloride/acrylonitrile copolymer Poly (vinylidene chloride-co-methyl acrylate). See Vinylidene chloride/methyl acrylate copolymer... 

Stannous oleate Stearyl alcohol Styrene/MA copolymer Terpene resin Tetrahydrofuran Titanium dioxide Toluene Tosylamide/formaldehyde resin Triethylene glycol Urea-formaldehyde resin Vinylidene chloride/acrylonitrile copolymer Vinylidene chloride/methyl acrylate copolymer Vinylidene chloride/vinyl chloride copolymer Zinc laurate cellophane, food-contact Aluminum stearates Ammonium tallate Hexamethoxymethylmelamine Nonoxynol-55 Nonoxynol-70... 

Also known as lyl-dichloroethylene Vinylidene chloride-acrylonitrile copolymer n. Any VC co-polymer containing 5-15% acrylonitrile, and mainly used as... 

Acetone and methyl ethyl ketone are valuable solvent components in acrylic/nitrocellulose automotive lacquers. Acetone is the solvent of choice in film coatings operations which use vinylidene chloride-acrylonitrile copolymer formulations. Other ketones that may be used in these film coating operations... 

The main use of the vinylidene chloride — acrylonitrile copolymers is as coatings for materials such as cellophane, paper and polyethylene. The coatings confer moisture and gas impermeability and they are heat-sealable. 

In the presence of a lubricant, the adhesion component of the sliding friction force Fg generally diminishes. Thus, surface energetics of the polymeric substrate do not affect friction. However, surface energetics of a lubricant can influence the friction. Presumably, the weakly held film reduces the shearing of the polymer surface and hence the interfacial adhesion. Owens found a linear correlation between critical surface tension of lubricants incorporated in vinylidene chloride-acrylonitrile copolymer and static friction of cellulose films (Fig. 12). 

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