Vinylidene Rubber

The main types of rubber used in the field of anti-corrosion are natural rubber, polyisoprene, polybutadiene, polyurethane, butyl rubber, styrene butadiene, nitrile rubber, ethylene propylene rubber, polychloroprene, silicone rubber, and vinylidene rubber. The wide ranges of available natural and synthetic rubbers offer a versatility of properties to suit almost every corrosive condition encountered in the process industries. 

L. D. Albia and M. M. Lynn, Chemistry of Elastomers Containing Vinylidene Fluoride, at the MCA Meeting of the Energy Rubber Group, Rubber Division, Educational Symposium, Arlington, Tex, Sept. 23, 1985, American Chemical Society, Washiagton, D.C. 

Asphalt, unmodified Coal tar Coal tar— epoxy Coal tar— nretlianes Epoxy phenolic- baked Epoxy amine- cnred Epoxy ester Fnrfnryl alcohol Phenolics, baked Polyesters (nnsati i-rated) Polyvinyl cliloracetates Vinyl ester Urethanes Vinylidene cliloride Clilorinated rubber... 

Comparison of Table 5.4 and 5.7 allows the prediction that aromatic oils will be plasticisers for natural rubber, that dibutyl phthalate will plasticise poly(methyl methacrylate), that tritolyl phosphate will plasticise nitrile rubbers, that dibenzyl ether will plasticise poly(vinylidene chloride) and that dimethyl phthalate will plasticise cellulose diacetate. These predictions are found to be correct. What is not predictable is that camphor should be an effective plasticiser for cellulose nitrate. It would seem that this crystalline material, which has to be dispersed into the polymer with the aid of liquids such as ethyl alcohol, is only compatible with the polymer because of some specific interaction between the carbonyl group present in the camphor with some group in the cellulose nitrate. 

Fluorinated rubbers, copolymers of hexafluoropropylene and vinylidene-fluorides, have excellent resistance to oils, fuels and lubricants at temperatures up to 200°C. They have better resistance to aliphatic, aromatic and chlorinated hydrocarbons and most mineral acids than other rubbers, but their high cost restricts their engineering applications. Cheremisinoff et al. [54] provide extensive physical and mechanical properties data on engineering plastics. A glossary of terms concerned with fabrication and properties of plastics is given in the last section of this chapter. 

Poly(ethylene terephtlhalate) Phenol-formaldehyde Polyimide Polyisobutylene Poly(methyl methacrylate), acrylic Poly-4-methylpentene-1 Polyoxymethylene polyformaldehyde, acetal Polypropylene Polyphenylene ether Polyphenylene oxide Poly(phenylene sulphide) Poly(phenylene sulphone) Polystyrene Polysulfone Polytetrafluoroethylene Polyurethane Poly(vinyl acetate) Poly(vinyl alcohol) Poly(vinyl butyral) Poly(vinyl chloride) Poly(vinylidene chloride) Poly(vinylidene fluoride) Poly(vinyl formal) Polyvinylcarbazole Styrene Acrylonitrile Styrene butadiene rubber Styrene-butadiene-styrene Urea-formaldehyde Unsaturated polyester... 

EPDM backbone, together with the carbonyl and ether groups generated on the rubber itself causes the carbonyl and ether absorptions to increase. The absorption at 1630 cm of the fraw -vinylene bonds of TMPTA is mainly due to the grafting of TMPTA onto EPDM and partly due to the formation of vinylidene bonds at the chain ends on irradiation. The absorptions at 1460 and 1379 cm due to >CH2 scissoring vibration and —CH3 stretching vibration, respectively, result from the rubber and the grafted TMPTA. 

Vinylidene fluoride-hexafluoropropene rubber good good poor... 

The isoprene units in the copolymer impart the ability to crosslink the product. Polystyrene is far too rigid to be used as an elastomer but styrene copolymers with 1,3-butadiene (SBR rubber) are quite flexible and rubbery. Polyethylene is a crystalline plastic while ethylene-propylene copolymers and terpolymers of ethylene, propylene and diene (e.g., dicyclopentadiene, hexa-1,4-diene, 2-ethylidenenorborn-5-ene) are elastomers (EPR and EPDM rubbers). Nitrile or NBR rubber is a copolymer of acrylonitrile and 1,3-butadiene. Vinylidene fluoride-chlorotrifluoroethylene and olefin-acrylic ester copolymers and 1,3-butadiene-styrene-vinyl pyridine terpolymer are examples of specialty elastomers. 

MPR (Melt Processable Rubber), a blend of vinylidene chloride and crosslinked EVA,... 

Viton A — trademark for a synthetic rubber derived from vinylidene fluoride and hexafluoropropylene... 

Fluorocarbon Resins. This term includes polytetrafluoroethylene, polymers of chloro-trifluoroethylene (fluorothene), vinylidene fluoride (H2C CF2)j hexafluoropropylene (C3Ffl) and similar compds. These polymers are thermoplastic, inert to chemicals and oxidation. They have high heat stability, retain their useful props at both extremely low and high temps, have high electrical resistance to moisture. The materials are available as re sins, powders, and dispersions, and as films, sheets, tubes, rods and tapes. Some of them are rubber-like. Commercially available varieties are Kel-F , Teflon , Fluorel , Aclar and "Halon ... 

Copolymer of styrene and acrylonitrile Copolymer of styrene and butadiene Natural rubber Chlorinated polyethylene Chlorosulfonated polyethylene Polyamides Polyesters Polyurethanes Polysulfones Polyacrylates Polyacrylamides Polydimethylsiloxane Copolymer of vinylidene fluoride and hexafluoropropylene... 

Emulsion polymers - [POLYMERS] (Vol 19) -acrylic elastomers [ELASTOMERS, SYNTHETIC - ACRYLICELASTOMERS] (Vol 8) -of acrylic monomers [ACRYLIC ESTER POLYMERS - SURVEY] (Vol 1) -of acrylonitrile [ACRYLONITRILE POLYMERS - SURVEY AND SAN (STYRENE-ACRYLONITRILECO-POLYMERS)] (Vol 1) -of methacrylic monomers [METHACRYLIC POLYMERS] (Vol 16) -nitrile rubber by [ELASTOMERS, SYNTHETIC - NITRILE RUBBER] (Vol 8) -of styrene/butadiene [STYRENE-BUTADIENERUBBER] (Vol 22) -synthetic rubber by [ELASTOMERS, SYNTHETIC - SURVEY] (Vol 8) -ofVDF [FLUORINECOMPOUNDS,ORGANIC-POLY(VINYLIDENE FLUORIDE)] (Volll) -for medical diagnostic reagents [MEDICAL DIAGNOSTIC REAGENTS] (Vol 16)... 

Bessarabov s devices use composite membranes consisting of a thin silicone rubber polymer layer coated onto a microporous poly(vinylidene fluoride) support layer. These membranes have high fluxes and minimal selectivities for the hydrocarbon gases, but the dense silicone layer provides a more positive barrier to bleed-through of liquid than do capillary effects with simple micro-porous membranes. 

In 1942, various materials, such as resinous chlorinated paraffin, chlorinated rubber, chlorinated alkyd resins, and vinyl and vinylidene resins were unavailable for use in fire-retardant paints. Such chlorinated binders as were available were in critical demand for flameproofing fabrics. The present availability of such materials... 

Footnotes (a) Gaskets are also available in other materials, such as hydrogenated nitrile, neoprene, butyl rubber, hypalon, silicon rubber to meet various application requirtnents. (b) Viton is a Du Pont Co. trademark for a series of fluoroelastorners based on the copolymer of vinylidene fluoride and hexafluoropropylene. 

As an illustration, Fig. 18.6 shows the permeability of nitrogen (at room temperature) for a great variety of polymers (elastomers, semi-crystalline polymers and glassy polymers). It can be seen that the values of P vary by a factor of nearly one million if silicone rubber on the one hand is compared with poly(vinylidene chloride) on the other ... 

Dry chlorine has a great affinity for absorbing moisture, and wet chlorine is extremely corrosive, attacking most common materials except Hastelloy C, titanium, and tantalum. These metals are protected from attack by the acids formed by chlorine hydrolysis because of surface oxide films on the metal. Tantalum is the preferred construction material for service with wet and dry chlorine. Wet chlorine gas is handled under pressure using fiberglass-reinforced plastics. Rubber-lined steel is suitable for wet chlorine gas handling up to 100 °C. At low pressures and low temperatures PVC, chlorinated PVC, and reinforced polyester resins are also used. Polytetrafluoroethylene (PTFE), poly (vinylidene fluoride) (PVDF), and... 

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