Ethylene-Propylene Copolymers and Terpolymers

Commercial grades of ethylene-propylene copolymers (EPR) contain 60-75 mol% of ethylene to minimize crystallization. The addition of a third monomer, such as 1,4-hexadiene, dicyclopentadiene, or 5-ethylidene-2-norbornene, produces generally amorphous faster-curing elastomers. A large number of such terpolymers, referred to as EPDM, is available commercially. Their properties, performance, and response to radiation vary considerably depending on macrostructure, ethylene/propylene ratio, as well as on the type, amount, and distribution of the third monomer. 

When EPDM is irradiated, the nature of the radical formed depends on the third monomer used and, as in most cases, the radical concentration increases linearly with dose.  

The cross-linking rate of EPR by radiation comes close to that of polypropylene. EPDM terpolymers exhibit an enhanced cross-linking rate, and it increases with the diene content. However, not only the cross-linking rate, but also a greater yield of scissions results from the addition of the third monomer. Cross-linking of EPR can be promoted by the addition of a variety of additives, particularly by those that were found effective in polypropylene. Tetravinyl silane, chlorobenzene, nitrous oxide, allyl acrylate, neopentyl chloride, and N-phenyl maleimide were reported to promote the process. 

Extender oils were foxmd to cause a considerable increase in the dose required to attain the optimum cure. This can be explained by reaction of transienf infermediafes formed on the irradiated polymer chain with the oil and with the energy transfer, which is particularly effective when the oil contains aromatic groups. Thus, the ranking of oils as to their cure inhibition is aromatic naphtenic aliphatic. This aspect is very important because many carbon-black-reinforced EPDM compounds contain frequently 100 phr or more oil. 

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Organic peroxides are used in the polymer industry as thermal sources of free radicals. They are used primarily to initiate the polymerisation and copolymerisation of vinyl and diene monomers, eg, ethylene, vinyl chloride, styrene, acryUc acid and esters, methacrylic acid and esters, vinyl acetate, acrylonitrile, and butadiene (see Initiators). They ate also used to cute or cross-link resins, eg, unsaturated polyester—styrene blends, thermoplastics such as polyethylene, elastomers such as ethylene—propylene copolymers and terpolymers and ethylene—vinyl acetate copolymer, and mbbets such as siUcone mbbet and styrene-butadiene mbbet. 

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. 

PVC, another widely used polymer for wire and cable insulation, crosslinks under irradiation in an inert atmosphere. When irradiated in air, scission predominates.To make cross-linking dominant, multifunctional monomers, such as trifunctional acrylates and methacrylates, must be added. Fluoropolymers, such as copol5miers of ethylene and tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), are widely used in wire and cable insulations. They are relatively easy to process and have excellent chemical and thermal resistance, but tend to creep, crack, and possess low mechanical stress at temperatures near their melting points. Radiation has been found to improve their mechanical properties and crack resistance. Ethylene propylene rubber (EPR) has also been used for wire and cable insulation. When blended with thermoplastic polyefins, such as low density polyethylene (LDPE), its processibility improves significantly. The typical addition of LDPE is 10%. Ethylene propylene copolymers and terpolymers with high PE content can be cross-linked by irradiation. ... 

Natural Rubber and Synthetic Polyisoprene Polybutadiene and Its Copolymers Polyisobutylene and Its Copolymers Ethylene-Propylene Copolymers and Terpolymers Polychloroprene Silicone Elastomers Fluorocarbon Elastomers Fluorosilicone Elastomers Electron Beam Processing of Liquid Systems Grafting and Other Polymer Modifications... 

Ethylene propylene rubber (EPR) has been also used for wire and cable insulation. When blended with thermoplastic polyefins such as LDPE its processibility improves significantly. The typical addition of LDPE is 10%. Ethylene propylene copolymers and terpolymers with high PE content can be cross-linked by irradiation.34... 

Applications of ethylene-propylene copolymers and terpolymers include automotive (the major use area), thermoplastic olefin elastomers, single-ply roofing, viscosity index improvers for lube oils, wire and cable insulation, hose, appliance parts, and polymer modification. 

Szewczyk, H., Zielasko, A. Determination of propylene in ethylene-propylene copolymers and terpolymers with dienes by infrared spectroscopy. Polimery 13, 415-418 (1968). 

The major types of impact modifiers are acrylics, styrenics including methacrylate-butadiene-styrene (MBS) copolymers and Acrylonitrile-Butadiene-Styrene Polymers, chlorinated polyethylene (CPE), EVA copolymers, and the ethylene-propylene copolymers and terpolymers (EPR and EPDM respectively). The major market for impact modifiers is in PVC, although they are used in a wide range of other polymers such as polyolefins and engineering polymers. 

ISO 9924-1, Determination of the composition of vulcanisates and uncured compounds by thermogravimetry. Part 1 Butadiene, ethylene-propylene copolymer and terpolymer, isobutene-isoprene, isoprene and styrene-butadiene rubbers. International Organisation for Standardization, Geneva (1993). 

EPM, EPDM Ethylene Propylene Ethylene Propylene copolymer and terpolymer Water, steam and brake fluids Mineral oils and sovents, aromatic hydrocarbons... 

Ethylene-propylene copolymers and terpolymers can certainly be considered the most interesting family of elastomers to appear in recent years and they are also well accepted by the rubber industry. 

ASTM Method D3900-95 (2000) Standard Test Methods for Rubber-Raw Determination of Ethylene Units in EPM (Ethylene-Propylene Copolymers) and EPDM (Ethylene-Propylene-Diene Terpolymers). 

The only important industrial applications of such soluble catalysts are of those prepared from VC14, VOCl3, V(Acac)3, VO(OEt)Cl2, VO(OEt)2Cl, VO(OEt)3 or VO(OBu)3 as precursors and AlEt3, AlEt2Cl or AI(/-Buj2CI as activators, in heptane solution, by which ethylene/propylene copolymers and ethylene/propylene/non-conjugated diene terpolymers are produced [72]. The AW molar ratio in these catalysts does not usually exceed a value of 3 1. 

Orientations in elongated mbbers are sometimes regular to the extent that there is local crystallization of individual chain segments (e.g., in natural rubber). X-ray diffraction patterns of such samples are very similar to those obtained from stretched fibers. The following synthetic polymers are of technical relevance as mbbers poly(acrylic ester)s, polybutadienes, polyisoprenes, polychloroprenes, butadiene/styrene copolymers, styrene/butadiene/styrene tri-block-copolymers (also hydrogenated), butadiene/acrylonitrile copolymers (also hydrogenated), ethylene/propylene co- and terpolymers (with non-conjugated dienes (e.g., ethylidene norbomene)), ethylene/vinyl acetate copolymers, ethyl-ene/methacrylic acid copolymers (ionomers), polyisobutylene (and copolymers with isoprene), chlorinated polyethylenes, chlorosulfonated polyethylenes, polyurethanes, silicones, poly(fluoro alkylene)s, poly(alkylene sulfide)s. 

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%),... 

The same authors report the formation of copolymers and terpolymers of tetramethylene urea, 7-butyrolactone, and ethylene carbonate or 1,2-propylene carbonate <2004MM6755>. 

At room temperature, PE is a semi-crystalline plastomer (a plastic which on stretching shows elongation like an elastomer), but on heating crystallites melt and the polymer passes through an elastomeric phase. Similarly, by hindering the crystallisation of PE (that is, by incorporating new chain elements), amorphous curable rubbery materials like ethylene propylene copolymer (EPM), ethylene propylene diene terpolymer (EPDM), ethylene-vinyl acetate copolymer (EVA), chlorinated polyethylene (CM), and chlorosulphonated polyethylene (CSM) can be prepared. 

Products The process can produce a broad range of propylene-based polymers, including homopolymer PP, various families of random copolymers and terpolymers, heterophasic impact and speciality impact copolymers (up to 25% bonded ethylene), as well as high-stiffness, high-clarity copolymers. 

Note ETFE, copolymer of ethylene and tetrafluoroethylene HTE, terpolymer of hexafluoropropyl-ene, tetrafluoroethylene and ethylene FEP, fluorinated ethylene-propylene copolymer PVDF, poly(vinylidene fluoride) THV, terpolymer of tetrafluorioethylene, hexafluoropro-pylene and vinylidene fluoride. 

Daikin Industries DuPont Fluoroproducts Note PTFE, polytetrafluoroethylene CTFE, chlorotriflua oethylene EFEP, per-fluorinated copolymer of ethylene and propylene ETFE, copolymer of ethylene tetrafluoroethylene PFPE, perfluorinated polyether EClFE, copolymer of ethylene and chlorotrifluoroethylene HIE, ter-polymer of hexafluoropropylene, tetrafluoroethylene, and ethylene MFA, copolymer of perfluoromethyMnylether and tetrafluoroethylene PEA, copolymer of perfluoropropylvinylether and tetrafluoroethylene FEP, fluorinated ethylene-propylene copolymer PVDF, poly(vinylidene fluoride) THV, terpolymer of tetrafluoroethylene, hexafluoroprqjylene, and vinyUdene fluoride PCTFE, poly(chlorotriflua oethylene). 

Another commercial application of organoaluminum compounds is as catalysts for the ring-opening polymerization of epoxides to form homopolymers of epichlorohydrin (ECH) and copolymers and terpolymers of ECH, ethylene oxide, propylene oxide, and allyl glycidyl ether.The resulting... 

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