Nitrile-epichlorohydrin rubber

The rubbers may be vulcanised by conventional accelerated sulphur systems and also by peroxides. The vulcanisates are widely used in petrol hose and seal applications. Two limiting factors of the materials as rubbers are the tendency to harden in the presence of sulphur-bearing oils, particularly at elevated temperatures (presumably due to a form of vulcanisation), and the rather limited heat resistance. The latter may be improved somewhat by Judicious compounding to give vulcanisates that may be used up to 150°C. When for the above reasons nitrile rubbers are unsatisfactory it may be necessary to consider acrylic rubbers (Chapter 15), epichlorohydrin rubbers (Chapter 19) and in more extreme conditions fluororubbers (Chapter 13). 

Epichlorohydrin rubber Thermoplastic polyurethanes Nitrile rubber... 

Fig. 3. Plot of Young s storage modulus versus temperature in degrees Centigrade at 10 Hz for nitrile-epichlorohydrin blend and chlorobutyl rubber.

Polymers Resins I Butyl Rubber, Epichlorohydrin Elastomers, Ethylene Propylene Rubber, Hypalon (TM) Production, Neoprene Production, Nitrile Butadiene Rubber, Polybutadiene Rubber, Polysulfide Rubber, Styrene-Butadiene Rubber Latex 07/31/97... 

CR is superior to NR or SBR as a barrier against gas permeation, but it does not exhibit as low permeability as do butyl rubbers, epichlorohydrin rubbers, or nitrile rubbers. 

Acrylate Rubber Epichlorohydrin Rubber Nitrile Rubber... 

FKMs are coextruded with lower-cost copolymers such as etliylene acrylic copolymer. They can be modihed by blending and vulcanizing with other synthetic rubbers such as silicones, ethylene propylene rubber (EPR) and ethylene propylene diene monomer (EPDM) rubbers, epichlorohydrin, and nitriles. Fluoroelastomers are blended with modihed nitrile butadiene rubber (NBR) to obtain an intermediate performance-cost balance. These blends are useful for underhood applications in environments outside the engine temperature zone such as timing chain tensioner seals. Fluoroelastomers can also be blended with fluorosilicones and other high-temperature polymers to meet engine compartment environments and cost-performance balance. 

The copolyesters resistance to nonoxidizing acids, some aliphatic hydrocarbons, aromatic fuels, hot oils, and hydraulic fluids ranges from good to excellent. Thus, they compete with such rubbers as nitriles, epichlorohydrins, and acrylates. However, hot polar materials, strong mineral acids and bases, and chlorinated solvents and creosols degrade the copolyesters. Their weather resistance is low but can be improved considerably, with UV stabilizers and carbon-black additives. 

Ta b I e 5.62 Upper and lower temperature limits for elastomeric materials (R C backbone with unsaturated units, M C backbone with only saturated units, 0 both C and 0 in the backbone, U C, N and 0 in the backbone, T C and S in the backbone, Q siloxane backbone NR natural rubber, IR isoprene rubber, BR butadiene rubber, CR chloroprene rubber, SBR styrene butadiene rubber, NBR nitrile rubber, HR butyl rubber, EPDM ethylene propylene ter-rubber, EAM ethylene vinyl acetate rubber, FKM fiuoro rubber, ACM acrylate rubber, CSM chlorosulfonated polyethylene, CM chlorinated polyethylene, ECO epichlorohydrin rubber (epichlorohydrin, ethylene oxide), AU polyurethane rubber (did), EU polyurethane rubber (diisocyanate), VMQ silicone rubber) specialties [229]... 

Some of the discussed additives may affect electrical properties of the materials. There is not much information published on this subject. It is known from literature that fluoropolymer additives made a dramatic improvement in the processing rates of several polymers (ethylene oxide epichlorohydrin copolymer, silicone, polyacrylate, nitrile butadiene rubber, and ethylene propylene diene terpolymer) without affecting the dielectric constant and dissipation factors. It can be assumed that a similar effect can be obtained with some silicone additives, but in the remaining cases, these properties have to be analyzed if they are of importance. 

Recommended for polymers chlorinated rubber, epichlorohydrin, hydrogenated nitrile, hydrogenated rubber, NBR, CR, PVC ... 

The majority of plasticiser consumption is in CR and NBR. Plasticisers are also technically important in chlorosulphonated polyethylene, hydrogenated nitrile, ethyl acrylate copolymer, epichlorohydrin copolymer and ethylene-acrylic terpolymer. At around 10 kt/annum (Europe), total consumption of plasticisers is on a much smaller scale than the process oils used in hydrocarbon rubbers. Typical addition levels are below 20 phr. 

Epichlorohydrin (ECO) has excellent resistance to fuel and oil swell. The ECOs show a volume swell of 35% at room temperature compared to 70% for a medium ACN—nitrile rubber in ASTM Reference Fuel C. The copolymer has a low temperature brittle point of —40°C and the homopolymer,... 

ACIDO CLOROACETICO (Spanish) (79-11-8) Combustible solid (flash point 258°F/126°C). Aqueous solution is a strong acid violent reaction with strong bases. Incompatible with sulfuric acid, ammonia, alcohols, aliphatic amines, alkanolamines, alky-lene oxides, epichlorohydrin, isocyanates, strong oxidizers. Attacks some plastics, rubbers, and coatings, including nitrile rubber, PVC, and polyvinyl alcohol. Attacks most metals in the presence of moisture. 

ACIDO METACRILICO (Spanish) (79-41-4) Combustible liquid (flash point 152°F/ 67°C oc). A reducing agent. Violent reaction with oxidizers, strong acids, alkalis. Unless inhibited (100 ppm of the monomethyl ether of hydroquinone is recommended), can polymerize violently. Polymerization can be caused by elevated temperatures, peroxides, sunlight, or hydrochloric acid. Incompatible with ammonia, amines, isocyanates, alkylene oxides, epichlorohydrin. Attacks metals, natural rubber, neoprene, nitrile, and some plastics including PVC and polyvinyl alcohol. The uninhibited monomer vapor may block vents and confined spaces by forming a solid polymer material. 

DIMETHYLNITROSAMINE, A,Af-DIMETHYLNITROSAMINE, or DIMETHYLNI-TROSOAMINE (62-75-9) An organic base. Incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, cellulose nitrate, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, isocyanates, ketones, glycols, maleic anhydride, nitrates, phenols, vinyl acetate. May increase the explosive sensitivity of nitromethane. UV light, strong oxidizers can cause reactions. Store in dark bottles. Attacks natural and nitrile rubbers, neoprene, polyvinyl alcohol, PVC, Viton . 

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