Ethylene propylene diene

The high-resolution Py-GC pyrograms obtained by Yamada and co-workers [59] were interpreted with regard to ethylidene norbornene (ENB) content. Several characteristic peaks of the degradation product were interpreted in terms of sequence distribution and ethylene-propylene composition. 

The composition of the polymers examined in this study is listed in Table 5.7. Sample A is a random copolymer whereas the remainder are random terpolymers. Propylene contents were determined by the IR method using the absorbance ratio of A at 1150 cm (8.69 pm) to A at 720 cm (13.89 pm) [60]. 

Relative peak intensities of LE above C o increase with the rise of ethylene content in the EPDM. The fact that the peak of the propylene trimer (P3) is observed while the tetramer peak (P4) is not, suggests that at least the triad propylene sequence (-CH2-CH(CH3)-)3 exists in the polymer chain. Furthermore, intensity of the P3 peak decreases as the ethylene content rises in the EPDM. 

A relationship exists between the peak intensities of the characteristic products such as 1-0 (Cg), 2-MO (Cg), and 1-0 (Cjq) and the E/P content in EPDM. In general, as the ethylene content increases in the EPDM, the ethylene sequence length becomes longer, and the amormt of the isolated ethylene units decreases. As described previously, 1-0 (Cg) and 1-0 (Cjo) are formed from the longer ethylene sequences than the triad. Intensities of 1-0 (Cg) and 1-0 (Cm) monotonously increase with the rise of the ethylene content in the EPDM. Conversely, 2-MO (Cg), which is correlated to the isolated ethylene unit, monotonously decreases as the ethylene content increases. Consequently, these relations can be used to estimate the E/P composition in EPDM. 

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Ethylene-propylene-diene rubber is polymerized from 60 parts ethylene, 40 parts propylene, and a small amount of nonconjugated diene. The nonconjugated diene permits sulfur vulcanization of the polymer instead of using peroxide. 

EPDM in pLASTOTffiRS, SYNTHETIC - ETHYLENE-PROPYLENE-DIENE RUBBER] (Vol 8) -polycarbonate in [POLYCARBONATES] (Vol 19)... 

ELASTOTffiRS,SYNTHETIC - ETHYLENE-PROPYLENE-DIENE RUBBER] (Vol 8)... 

ELASTOPffiRS,SYNTHETic-POLYcm.OROPRENE Elastop rs, SYNTHETIC-ETHYLENE-PROPYLENE-DIENE RUBBER). Tires, hoses, belts, molded and extmded goods, and asphalt products consume ca 80% of the reclaimed mbber manufactured. Typical properties of reclaimed mbbers are shown in Table 5. 

At this point in the process, thermoplastic and chlorosulfonated polyethylene (CSPE) membranes are complete and are ready for packaging. In the case of ethylene—propylene—diene monomer (EPDM), the curing step occurs before the membrane is ready for packaging. The curing process is accomphshed by placing the membrane in a large vulcanizer where the material is heated under pressure to complete the cure. 

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. 

Fig. 1. SAE J200 Classification system for ASTM No. 3 oil where in volume swell nr = no requirement. EPDM is ethylene—propylene—diene monomer HR, butyl mbber SBR, styrene—butadiene mbber NR, natural mbber VMQ, methyl vinyl siUcone CR, chloroprene FKM, fluoroelastomer FVMQ, fluorovinyl methyl siUcone ACM, acryUc elastomers HSN, hydrogenated nitrile ECO, epichlorohydrin and NBR, nitrile mbber.

Ethylene—Propylene Rubber. Ethylene and propjiene copolymerize to produce a wide range of elastomeric and thermoplastic products. Often a third monomer such dicyclopentadiene, hexadiene, or ethylene norbomene is incorporated at 2—12% into the polymer backbone and leads to the designation ethylene—propylene—diene monomer (EPDM) mbber (see Elastomers, synthetic-ethylene-propylene-diene rubber). The third monomer introduces sites of unsaturation that allow vulcanization by conventional sulfur cures. At high levels of third monomer it is possible to achieve cure rates that are equivalent to conventional mbbers such as SBR and PBD. Ethylene—propylene mbber (EPR) requires peroxide vulcanization. 

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