EPDM, EPM

There are two general types of polymers based on ethylene and propylene ethylene-propylene rubber (EPM) and ethylene-propylene terpolymer (EPDM). EPM accounts for approximately 20 percent of the polyolefin rubber produced. Comprising a totally saturated polymer, these materials require free-radical sources to cross-link. EPDM was developed to overcome this cure... 

Aztec . [Catalyst I ources] Peroxide deiivs. crosdinking agoit catalyst in polyethylene crosslinl g, styrene polymerization, polyester resins vulcanizing agent for SB NBR, EPDM, EPM, silicones initiate in polymer-izadort... 

Uses Vulcanizing agent for SBR, NBR, EPDM, EPM, CPE, and silicones crosslinking agent for unsat. PE and EVA Manuf./Distrib. Aldrich http //www.sigma-aldrich.com... 

Ethylene monomer is used in a polymerization process to produce EPDM, EPM, AEM, and FKM elastomers. Ethylene monomer is also used to make block polymers such as SEES and SEPS thermoplastic elastomers. 

EPM/EPDM compounding pLASTOPmRS, SYNTHETIC - ETTTYLENE-PROPYLENE-DIENE RUBBER] (Vol 8)... 

EPM/EPDM compounding pLASTOPffiRS, SYNPPiETIC - EPPiYLENE-PROPYLENE-DIENE RUBBER] (Vol 8) -in fats and oils [CARBOXYLIC ACIDS - ECONOMIC ASPECTS] (Vol 5)... 

NR, natural mbber CR, chloroprene SRs, synthetic mbbers IR, natural isoprene SBR, styrene—butadiene mbber BR, butadiene EPDM, ethylene—propjiene-diene EPM, ethylene—propylene polymer HR, isobutylene—isoprene NBR, nitrile—butadiene. 

Copolymers of ethylene and propylene (EPM) and terpolymers of ethylene, propylene, and a diene (EPDM) as manufactured today are mbbers based on the early work of G. Natta and co-workers (1). A genetic formula for EPM and EPDM may be given as follows, where ra = (- GO mol%),... 

EPM can be vulcanised radically by means of peroxides. A small amount of built-in third diene monomer in EPDM permits conventional vulcanisa tion with sulfur at the pendent sites of unsaturation. 

Even though EPM and EPDM mbbers have been commercially available for more than 30 years, the technology concerning these products, both their production and their appHcations, is stiU very much under development. 

EPM and EPDM mbbers are produced in continuous processes. Most widely used are solution processes, in which the polymer produced is in the dissolved state in a hydrocarbon solvent (eg, hexane). These processes can be grouped into those in which the reactor is completely filled with the Hquid phase, and those in which the reactor contents consist pardy of gas and pardy of a Hquid phase. In the first case the heat of reaction, ca 2500 kJ (598 kcal)/kg EPDM, is removed by means of cooling systems, either external cooling of the reactor wall or deep-cooling of the reactor feed. In the second case the evaporation heat from unreacted monomers also removes most of the heat of reaction. In other processes using Hquid propylene as a dispersing agent, the polymer is present in the reactor as a suspension. In this case the heat of polymerisation is removed mainly by monomer evaporation. 

Under polymerisation conditions, the active center of the transition-metal haHde is reduced to a lower valence state, ultimately to which is unable to polymerise monomers other than ethylene. The ratio /V +, in particular, under reactor conditions is the determining factor for catalyst activity to produce EPM and EPDM species. This ratio /V + can be upgraded by adding to the reaction mixture a promoter, which causes oxidation of to Examples of promoters in the eadier Hterature were carbon tetrachloride, hexachlorocyclopentadiene, trichloroacetic ester, and hensotrichloride (8). Later, butyl perchlorocrotonate and other proprietary compounds were introduced (9,10). 

Production capacities of EPM/EPDM of the largest manufacturers are Hsted in Table 2. 

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