Vinylidene chloride-vinyl acrylonitrile copolymers

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... 

Fig. 13. Variation of the interaction parameter (%) with PCL contents of blends of PCL with several Saran copolymers ( ) vinylidene chloride-vinyl chloride copolymer, (O)vinyli-dene chloride-acrylonitrile copolymer, ( ) vinylidene chloride-vinyl acetate copolymer data taken from [74]...

In addition to homopolymers of varying molecular and particle structure, copolymers are also available commercially in which vinyl chloride is the principal monomer. Comonomers used eommercially include vinyl acetate, vinylidene chloride, propylene, acrylonitrile, vinyl isobutyl ether, and maleic, fumaric and acrylic esters. Of these the first three only are of importance to the plastics industry. The main function of introducing comonomer is to reduce the regularity of the polymer structure and thus lower the interchain forces. The polymers may therefore be proeessed at much lower temperatures and are useful in the manufacture of gramophone records and flooring compositions. 

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. 

The first two modacrylic fibers ever introduced in the United States were Dynel (by Union Carbide) in 1949 and Verel (by Tennessee Eastman) in 1956. The former was a copolymer of 60 percent vinyl chloride and 40 percent acrylonitrile, and the latter was said to be a 50-50 copolymer of vinylidene chloride and acrylonitrile with perhaps a third component graft-copolymerized onto the primary material to secure dyeability. SEF and its version for wigs, Elura , were introduced by Monsanto Fibers in 1972. A few foreign manufacturers are making modacrylic fibers, but the only modacrylic fiber currently in production in the United States is SEF . 

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. 

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. 

Saran Dow Copolymers of vinylidene chloride, vinyl chloride and acrylonitrile... 

Modacryl ic fibers are formed from copolymers consisting of 35%85% acrylonitrile and a suitable vinyl comonomer or comonomers such as vinyl chloride, vinylidene chloride, vinyl acetate, vinyl pyrollidone, or methyl acrylate. The modacrylics generally resemble acrylics and have a warm pleasing hand and good drapability, resiliency and wrinkle resistance. They are more heat sensitive but more flame resistant than acrylics and have generally been used in specialty applications. Modacrylic fiber exhibits a more thermoplastic character than the related acrylic fibers. 

The PVDC homopolymer is difficult to process. Thus, copolymers of vinylidene chloride-vinyl chloride, vinylidene chloride-alkyl acrylate, vi-nylidene chloride - acrylonitrile, which are easier to process than PVDC homopolymer, are widely used in industrial processes. The choice of comonomer significantly affects the properties of the copolymer. Table 8 illustrates the reactivity ratios of some important monomers (monomer 1 = VDC) [76]. 

Acrylonitrile-butadiene-styrene (ABS) terpolymer. Acrylonitrile and styrene are grafted on polybutadiene. It is preferred over homopolymers because of impact resistance, dimensional stability and good heat-distortion resistance. It is an extremely important commercial copolymer and, in several applications, it is blended with other polymers (e.g., PVC or polycarbonates) in order to increase their heat-distortion temperatures. When methyl methacrylate and styrene are grafted on polybutadiene, a methyl methacrylate-butadiene-styrene MBS copolymer is formed. Vinylidene chloride-vinyl chloride copolymer. Because of its toughness, flexibility, and durability, the copolymer is used for the manufacture of filaments for deck chair fabrics, car upholstery, and doll s hair. Biaxially stretched copolymer films are used for packaging. 

Vinylidene chloride and vinyl chloride lead to the copolymer known as Saran. Other commercial copolymers are produced from vinyl chloride and acrylonitrile (Dynel), and from maleic anhydride and styrene. 

Vinyhdene chloride copolymers are available as resins for extmsion, latices for coating, and resins for solvent coating. Comonomer levels range from 5 to 20 wt %. Common comonomers are vinyl chloride, acrylonitrile, and alkyl acrylates. The permeability of the polymer is a function of type and amount of comonomer. As the comonomer fraction of these semicrystalline copolymers is increased, the melting temperature decreases and the permeability increases. The permeability of vinylidene chloride homopolymer has not been measured. 

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. 

Poly(vinylidene chloride) (XLII) and its copolymers with vinyl chloride, acrylonitrile, and acrylates, usually produced by the suspension or emulsion process, are useful as oil, fat, oxygen, and moisture-resistant packaging films (Saran wrap), containers, coatings, tank liners, and monofilaments in drapery fabrics and industrial filter cloths. 

Abbreviations for plastics ABS, acrylonitrile-butadiene-styrene CPVC, chlorinated poly vinyl chloride ECTFE, ethylene-chlorotrifluoroethylene ETFE, ethylene-tetrafluoroethylene PB, polybutylene PE, polyethylene PEEK, poly ether ether ketone PFA, perfluoroalkoxy copolymer POP, poly phenylene oxide PP, polypropylene PVC, polyvinyl chloride PVDC, poly vinylidene chloride PVDF, poly vinylidene fluoride. 

Vinylidene chloride is used principally in copolymers with vinyl chloride, acrylonitrile and other monomers for packaging materials, adhesives and synthetic fibres (Lewis, 1993). 

Many synthetic laiices exist. They contain butadiene and. styrene copolymers telasioiiieric). styrene - butadiene copolymers ireximms). butadiene and acrylonitrile, chloroprene copolymers, methacrylate and acrylate ester copolymers, vinyl aeelate copolymers, vinyl and vinylidene chloride copolymers, ethylene copolymers. Huorinated copolymers, acrylamide copolymers, styrene-acrolein copolymers, and pyrrole and pyrrole copolymers. Yluny of these lattee.s also have earboxylated versions. 

PS PSF PSU PTFE PU PUR PVA PVAL PVB PVC PVCA PVDA PVDC PVDF PVF PVOH SAN SB SBC SBR SMA SMC TA TDI TEFE TPA UF ULDPE UP UR VLDPE ZNC Polystyrene Polysulfone (also PSU) Polysulfone (also PSF) Polytetrafluoroethylene Polyurethane Polyurethane Poly(vinyl acetate) Poly(vinyl alcohol) poly(vinyl butyrate) Poly(vinyl chloride) Poly(vinyl chloride-acetate) Poly(vinylidene acetate) Poly(vinylidene chloride) Poly(vinylidene fluoride) Poly(vinyl fluoride) Poly(vinyl alcohol) Styrene-acrylonitrile copolymer Styrene-butadiene copolymer Styrene block copolymer Styrene butadiene rubber Styrene-maleic anhydride (also SMC) Styrene-maleic anhydride (also SMA) Terephthalic acid (also TPA) Toluene diisocyanate Ethylene-tetrafluoroethylene copolymer Terephthalic acid (also TA) Urea formaldehyde Ultralow-density polyethylene Unsaturated polyester resin Urethane Very low-density polyethylene Ziegler-Natta catalyst... 

Halogen-containing fibers namely modacrylics fibers are typically copolymers of vinyl chloride or vinylidene dichloride and acrylonitrile. Although these fibers do not melt-flow or drip, they shrink rapidly when exposed to the fire. Because of this, the best use of modacrylic fibers is in blends. 

The principal solution to fabrication difficulties is copolymerization. Three types of comonomers are commercially important vinyl chloride acrylates, including alkyl acrylates and alkylmethacrylates and acrylonitrile. When extrusion is the method of fabrication, other solutions include formulation with plasticizers, stabilizers, and extmsion aids plus applying improved extrusion techniques. The literature on vinylidene chloride copolymers through 1972 has been reviewed (1). 

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