Ethylene-propylene-diene monomer terpolymer

Much less recognized is the possible influence of tacticity on copolymer properties when a-olefin monomer units are a minor component, and crystallinity is not based on a tactic a-olefin sequence but on a different comonomer such as ethylene. In this chapter, this tacticity effect is shown for ethylene-rich ethylene/propylene (EP) copolymers, where the crystallizable sequences are based on ethylene, that is, a comonomer that does not have tacticity requirements. In particular, this chapter describes in detail the microstructure of EP copolymers having industrially relevant compositions (ethylene content 80-55 mol%), with particular focus on the placement of propylene units along the ethylene-based macromolecular chains and their influence on copolymer properties. This subject is, of course, related to the industrial relevance of EP copolymers and ethylene/propylene/diene monomer terpolymers (EPDMs) (collectively referred to as EP(D)Ms), which presently represent the most widely produced saturated rubbers. ... 

EPDM ethylene/propylene/diene monomer terpolymer... 

Acrylonitrile-Ethylene/Propylene-Styrene Copolymer AES is a terpolymer obtained by grafting styrene-acrylonitrile copolymer to ethylene-propylene or ethylene-propylene-diene monomer rubber. Similar to ABS except with improved weathering resistance. 

When ethylene is copolymerized with substantial amounts (>25%) of propylene an elastomeric copolymer is produced, commonly known as ethylene-propylene rubber (EPR) or ethylene-propylene monomer (EPM) rubber. When a diene, such as dicyclopentadiene, is also included, a terpolymer known as ethylene-propylene-diene monomer (EPDM) rubber is obtained. EPR and EPDM are produced with single site and Ziegler-Natta catalysts and are important in the automotive and construction industries. However, EPR and EPDM are produced in much smaller quantities relative to polyethylene. Elastomers display vastly different properties than other versions of industrial polyethylene and are considered outside the purview of this text. EPR and EPDM will not be discussed further. 

EPDM. Abbreviation for a terpolymer elastomer made from ethylene-propylene diene monomer. 

Polyolefin terpolymers contain three olefinic monomers. A well-known example is ethylene propylene diene monomer (EPDM). The diene (double bond) monomer is... 

A blend of low-density polyethylene (LDPE) polyethylene (LDPE) with the terpolymer ethylene-propylene-diene monomer rubber (EPDM) exhibits a synergistic effect on tensile strength if EPDM is partially crystalline, but a nonsynergistic effect if the EPDM is amorphous [65]. This example shows the dramatic effect that morphology can have on properties of polymer blends. The synergism apparently arises from a tendency for crystallites in the LDPE to nucleate crystalli2ation of ethylene segments in the EPDM. 

Copolymerization of ethylene and propylene produces an elastomeric polymer that is virtually inert because of the absence of carbon-carbon double bonds (EPM). Such polymers thus tend to be crossUnked with peroxides or by radiation. To improve the reactivity of ethylene-propylene copolymers, 1-10% of a third monomer can be added to give a terpolymer or ethylene-propylene-diene monomer (EPDM). The primary diene monomers used in EPDM are 1,4-hexadiene, dicyclopentadiene, and ethyUdene norbomene. Introduction of an unsaturated monomer such as ethylidene norbomene will enable use of sulfur-based crosslinking systems. 

Ethylene-propylene rubber is a synthetic hydrocarbon-based rubber made either from ethylene-propylene diene monomer or ethylene-propylene terpolymer. These monomers are combined in such a manner as to produce an elastomer with a completely saturated backbone and pendant unsaturation for sulfur vulcanization. As a result of this configuration, vulcanizates of EPDM elastomers are extremely resistant to attack by ozone, oxygen, and weather. 

The insulation system for pitched roofs usually provides the advantage of a continuous, homogeneous insulating layer with an economy in construction. Bitumen (asphalt) as well as its different versions modified with various polymers and a number of different roofing membranes, i.e., preformed or liquid applied sheets of PVC, terpolymer of ethylene-propylene-diene monomer (EPDM), chlorosulfonated polyethylene (Hypalon), PU, butyl rubber, polychloroprene (Neoprene) [36], all have been used as insulating layers. 

Both natural and synthetic rubbers are used as elastomeric linings. The most commonly used synthetic elastomers are NBR (acrylonitrile-butadiene), Hypalon (chlorosulfonated polyethylene), EPDM (ethylene-propylene-diene monomer), EPT (ethylene-propylene-diene terpolymer), SBR (styrene-butadiene), and neoprene (polychloroprene). A maximum use temperature of nS F/SOX is typical. 

Ethylene-propylene rubber is a synthetic hydrocarbon based rubber made either from ethylene-propylene diene monomer (EPDM) or from ethylene-propylene terpolymer (EPT). 

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)... 

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. 

Ethylene-propylene-diene terpolymers (EPDM), with their inherent complexity in structural parameters, owe their tensile properties to specific structures dictated by polymerization conditions, among which the controlling factor is the catalyst used in preparing the polymers. However, no detailed studies on correlation between tensile properties and EPDM structures have been published (l,2). An unusual vulcanization behavior of EPDMs prepared with vanadium carboxylates (typified by Vr g, carboxylate of mixed acids of Ccj-Cq) has been recently reported Q). This EPDM attains target tensile properties in 18 and 12 minutes at vulcanization temperatures of 150 and l60°C respectively, while for EPDMs prepared with V0Cl -Et3Al2Cl or V(acac) -Et2AlCl, about 50 and 0 minutes are usually required at the respective vulcanization temperatures, all with dieyclopentadiene (DCPD) as the third monomer and with the same vulcanization recipe. This observation prompted us to inquire into the inherent structural factors... 

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. 

These polyolefin rubbers are produced in two main types the saturated co-polymers, ethylene propylene rubber (EPM), and the unsaturated ethylene-propylene diene terpolymer (EPDM). The monomers are co-polymerised in ziegler natta type catalysts. The EPDM types are capable of sulfur vulcanisation as they contain, in addition to olefins, a non coagulated diene as the third monomer. 

The choice of date range is arbitrary. The number of journal articles for each year was obtained from a search of electronic version of English-based polymer and polymer-related journals using the keywords polyolefin and blends. Within polyolefin keyword, the subkeywords used in the search were polyethylene (PE, LLDPE, LDPE, HDPE, UHMWPE, PE, etc.), polypropylene (PP, iPP, sPP, aPP, etc.), polybutene-1, poly-4-methylpentene-l, ethylene-diene monomer, ethylene-propylene-diene terpolymer, ethylene propylene rubber, thermoplastic olefins, natural rubber (NR), polybutadiene, polyisobutylene (PIB), polyisoprene, and polyolefin elastomer. For the polyolefin blends patent search, polymer indexing codes and manual codes were used to search for the patents in Derwent World Patent Index based on the above keywords listed in the search strategy. 

US Environmental Protection Agency Ethylene-propylene diene terpolymer Expanded polyethylene Rubbers of ethylene-propylene monomer Ethylene-propylene rubber Expanded polystyrene Electrostatic-discharge dissipating... 

Terpolymer of ethylene, propylene, and a diene with the residual unsaturated portion of the diene in the side chain Ethylene-propopylene-diene-monomer rubber EPDM... 

Krishen [119] has described a procedure for the determination of these monomer units. He quantitatively analysed the gaseous pyrolysis products from natural rubber, styrene-butadiene rubber and ethylene-propylene diene terpolymer rubber by gas chromatography. He showed that the 2-methyl-2-butene peak was linear with the natural rubber content of the sample. Styrene-butadiene rubber was determined from the peak area of the 1,3-butadiene peak. The ethylene-propylene-terpolymer content was deducted from the 1-pentane peak area of the pyrolysis products. Some of the pyrolysis products identified are shown in Table 4.10. 

The preparation of ethylene copolymers (or terpolymers) such as linear low-density polyethylenes (LLDPE), ethylene/propylene elastomers (EP), ethylene/ propylene/diene terpolymers (EPDM) is also based on these catalytic systems. Stereoregular polyisoprene and polybutadiene elastomers are also obtained by this method of polymerization the formation of 1,4-m-polydienes requires the prior double coordination of the monomer onto the growing active center ... 

---