Ethylene-propylene-diene terpolymer compound

The most prevalent approach to achieve long-lasting and nonstaining ozone protection of rubber compounds is to use an inherently ozone-resistant, saturated backbone polymer in blends with a diene rubber. The ozone-resistant polymer must be used in sufficient concentration (minimum 25 phr) and must also be sufficiently dispersed to form domains that effectively block the continuous propagation of an ozone-initiated crack through the diene rubber phase within the compound. Elastomers such as ethylene-propylene-diene terpolymers, halogenated butyl mbbers, or brominated isobutylene-co-para-methylstyrene elastomers have been proposed in combination with NR and/or butadiene rubber. 

Thioureas mainly find use for the vulcanisation of CR, epichlorohydrin (ECO) and some ethylene propylene diene terpolymer (EPDM) compounds. They show high crosslinking activity, with usually adequate compound flow time before onset of the crosslinking. In EPDMs, the thioureas are used as activators for low activity third monomer types and, in the presence of calcium oxide desiccants, in free state vulcanisation of extrudates, etc. The use of thioureas can overcome the retardation caused by the desiccant. In this case some care must be taken otherwise overcompensation may occur. Thioureas are not used in food product applications and are a known health hazard, particularly for pregnant women. 

Post and co-workers [49] have used TG-FTIR to study the outgassing of a plasticiser (type and amount) from an ethylene-propylene-diene terpolymer (EPDM) compound. Figure 1.6 shows the thermogravimetric decomposition behaviour of the EPDM compound. The plasticiser emerges in the first mass-loss step, which was identified as adipic acid diisobutylester by on-line infrared analysis. 

Red lead is an ingredient generally used in all Neoprene compounds for tank linings for good water and chemical resistance. But it should not be used in compounds of Neoprene designed for contact with food or potable water. Tubes or pipes for conveying potable water are made of ethylene-propylene diene terpolymer (EPDM) rubbers. 

Assis et al. (2005) extracted and concentrated the volatile compounds of the coffee beverage via PV using a flat membrane of ethylene propylene diene terpolymer (EPDM). Shepherd et al. (2002) used PDMS hfs for orange juice aroma recovery. Zhang et al. (2006) used CA membranes for PV separation of a methanol-Cs mixture. 

Many accelerators are available as dust free dispersions, preferably in an ethylene-propylene diene terpolymer/polyvinyl acetate blend. These have the dual advantage of zero loss as dust when the pellets are crashed as they are mixed, and rapid incorporation into the compound due to their low melting point. These materials are of particularly value when the melting point of the dispersed chemical is relatively high and all show generally rapid dispersion rates, giving high batch-to-batch consistency. 

Ethylene propylene diene terpolymers (EPDM) can be used to improve the ozone resistance of bromobutyl/natural rubber binary polymer blends, eliminating the need for chemical antiozonants. Addition of 10 phr of EPDM (with a high ethylidene norbornene, ENB, content of9%) to a 50/50 bromobutyl rubber/natural rubber blend results in a compound vdth good static and dynamic ozone resistance. EPDM with a 5.7% ENB level is another suggested grade of polymer. 

METHOD 90 - DETERMINATION OF NATURAL RUBBER, STYRENE-BUTADIENE RUBBER AND ETHYLENE-PROPYLENE DIENE TERPOLYMER IN COMPOUNDED RUBBER STOCKS. PYROLYSIS - GAS CHROMATOGRAPHY. ... 

Ethylene-Propylene-Diene Terpolymer (EPDM) Compounds... 

Dithiophosphates. These compounds (13) are made by reaction of an alcohol with phosphoms pentasulfide, then neutralization of the dithiophosphoric acid with a metal oxide. Like xanthates, dithiophosphates contain no nitrogen and do not generate nitrosamines during vulcanization. Dithiophosphates find use as high temperature accelerators for the sulfur vulcanization of ethylene—propylene—diene (EPDM) terpolymers. 

Indirect, quantitative information on the behavior of ethylene-propylene based terpolymers in the presence of t-butoxy radicals have been obtained through kinetic studies carried out on model compounds of triene (III), (V), (VI) and on the reference diene ENB. The model compounds denoted (III,a), (V,f), (VI,a), and NB, were dissolved in isooctane which simulated the ethylene-propylene units present in EPTMs or EPDMs25. The approach was essentially that described by Szwarc et al.so>. 

Chloroprene rubber or, polychloroprene rubber Chlorotrifluoroethylene ethylene copolymers Cis-polyisoprene or, cis-l,4-polyisoprene Coumarone indene resins Diallyl phthalate Diallyl isophthalate Dough molding compound Elastomeric alloy melt processable rubber Elastomeric alloy thermoplastic vulcanizate Epichlohydrin rubber Epoxy or, epoxide Epoxy or, epoxide, with glass fiber Ethyl cellulose Ethylene acryic acid Ethylene propylene diene monomer (an EPR terpolymer)... 

Special method of vulcanization with peroxide, dependent on transfer reactions, has to be developed. On the other hand, the newer ethylene-propylene elastomers are terpolymers (EPT rubbers) which contain a small percentage of a third component with diene structure, which provides the double bonds necessary for the classic sulfur vulcanization. Such third-component compounds include the following ... 

EPDM is a terpolymer of ethylene, propylene, and a small amount of an unsaturated diene as a third monomer to provide a cure site. Unlike the elastomers previously discussed, the unsaturation in EPDM is not in the main chain, but it is pendent to the chain. Peroxide-based cure systems afford better aging resistance and low compression set. A comparison of a sulfur-based cure to two different peroxides in EPDM is shown in Table 21 (4). Initial properties for these three compounds are reasonably close. However, after air aging, the advantages of peroxide curing are apparent. Most dramatic is the improved compression set... 

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