Ethylene propylene terpolymer elastomer

The rheological properties of gum and carbon black compounds of an ethylene-propylene terpolymer elastomer have been investigated at very low shear stresses and shear rates, using a sandwich rheometer [50]. Emphasis was given to measurements of creep and strain recovery at low stresses, at carbon black flller contents ranging between 20 and 50% by volume. The EPDM-carbon black compounds did not exhibit a zero shear rate viscosity, which tended towards in-Anity at zero shear stress or at a finite shear stress (Fig. 13). This was explained... 

Most elastomers can be made iato either opea-ceUed or closed-ceUed materials. Natural mbber, SBR, nitrile mbber, polychloroprene, chlorosulfonated polyethylene, ethylene—propylene terpolymers, butyl mbbers, and polyacrylates have been successfuUy used (4,111,112). 

Elastomers. Ethylene—propylene terpolymer (diene monomer) elastomers (EPDM) use a variety of third monomers during polymerization (see Elastomers, ethyiene-propylene-diene rubber). Ethyhdenenorbomene (ENB) is the most important of these monomers and requires dicyclopentadiene as a precursor. ENB is synthesized in a two step preparation, ie, a Diels-Alder reaction of CPD (via cracking of DCPD) with butadiene to yield 5-vinylbicyclo[2.2.1]-hept-2-ene [3048-64-4] (7) where the external double bond is then isomerized catalyticaHy toward the ring yielding 5-ethyhdenebicyclo[2.2.1]-hept-2-ene [16219-75-3] (ENB) (8) (60). 

Prior to butyl mbber, the known natural and synthetic elastomers had reactive sites at every monomer unit. Unlike natural mbber, polychloroprene, and polybutadiene, butyl mbber had widely spaced olefin sites with aHyUc hydrogens. This led to the principle of limited functionahty synthetic elastomers that was later appHed to other synthetic elastomers, eg, chlorosulfonated polyethylene, siUcone mbber, and ethylene—propylene terpolymers. 

Sulfonated ethylene-propylene terpolymer Ionic Elastomer 3 Uni royal Thermoplastic elastomer... 

The polyacrylate and ethylene-acrylic copolymers and one of the ethylene-propylene terpolymers (Nordel) were the best of the Intermediate temperature elastomers. Except for resistance to compression set, these materials were Inferior to the silicones in thermal stability as measured by their retention of tensile properties. The other EPDM compounds and butyl rubber were considerably inferior to the above-mentioned elastomers. It is not expected that the service life of the tested materials will be limited solely by their ability to resist hydrolytic degradation. The only caulking compositions which retained moderate physical integrity on thermal aging were the silicones. 

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. 

CAS 25034-71-3 25038-36-2 25038-37-8 Synonyms EPDM EPT Ethylene-propylene-diene terpolymer Ethylene propylene terpolymer Classificatbn Elastomer... 

The process may easily be transformed for the synthesis of other elastomers and copolymers with a double bond in the backbone of the monomer unit. Therefore, the range of elastomers is extensive isoprene, butadiene, butadiene-styrene rubbers, ethylene-propylene terpolymer, and so on. 

Ethylene-propylene terpolymer (EPDM) is synthesized from ethylene, propylene, and a third monomer, a nonconjugated diene. The diene permits conventional sulfur vulcanization. The elastomer is exceptionally resistant to radiation and heat. The glass transition temperature is -60°C, and electrical properties are good. 

Polymer Chemical Stabilization Processes. Cellular rubber and ebonite are produced by chemical stabilization processes. Most elastomers can be made into either open-celled or closed-celled materials. Natural rubber, SBR, nitrile rubber, polychloroprene, chlorosulfonated polyethylene, ethylene-propylene terpolymers, butyl rubbers, and polyacrylates have been successfully used (110-112). 

This elastomer also exhibits good resistance to impact, abrasion, tearing, and cut growth over a wide temperature range. The physical and mechanical properties of ethylene-propylene rubber can be found in Table 4.14. Ethylene propylene terpolymer has similar physical properties. 

The comparison between the effects brought about during EB-irradiation of natural rubber, ethylene-propylene terpolymer (EPDM) and nitrile rubber emphasizes the satisfactory behavior of the last polymer [99C1, GOBI]. The gel fraction, chain scission and modification of the networks in these elastomers explain the changes in mechanical properties, i.e. the modulus increased and the elongation at break decreased with an increase in the irradiation dose (Fig. 66). 

Rubbers and elastomeric products for practical applications are usually blends of different elastomer types that develop specific domain morphologies at the microscale, and, therefore, they are a part of this chapter. The most common representatives of the ruhher family are natural ruhher (NR) and the synthetic polyhutadiene ruhher (PB). There are various copolymers of butadiene with styrene (styrene butadiene rubber, SBR) or acrylonitrile (acrylonitrile-butadiene rubber, NBR). Several elastomers have been developed for special purposes, such as EVA (ethylene vinyl acetate copolymer), PU (polyurethane), EPDM (ethylene propylene terpolymer), and siUcone rubber. 

VISTALON elastomers are classified generically as either ethylene-propylene copolymers (EPM) or ethylene-propylene terpolymers saturated hydrocarbon chain which makes them highly resistant to attack by chemical agents such as oxygen, ozone, acids, and the like that seek to react at the site of a double bond. 

There are many well-known examples of industrial problems that arise in ternary systems of two polymers and a low molecular weight compound. Consider a blend of a polar elastomer (e.g., butadiene acrylonitrile copolymer, NBR) and a hydrocarbon elastomer (e.g., ethylene propylene terpolymer, EPDM (Section 1.3.2))... 

In the early history of polypropylene technology, blends with ethylene propylene copolymer were introduced for toughening polypropylene. Subsequently block copolymers of polypropylene with random ethylene propylene copolymer rubber were produced in the polymerization reaction. Dynamic vulcanization of ethylene propylene terpolymer in blends with polypropylene together with hydrocarbon oils was a third technology. The first TPO was elastomer (ethylene)-modified propylene (EP polymer) marketed to overcome polypropylene s weakness that cold temperature negatively impacts resistance. 

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. 

EPDM is a terpolymer of ethylene, propylene, and a small amount (<10%) of an unsaturated diene 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 cure gives superior aging resistance and low compression set. 

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. 

Medintseva, T.I., Dreval, V.E., Erina, N.A., and Prut, E.V., Rheological properties thermoplastic elastomers based on isotactic polypropylene with an ethylene-propylene-diene terpolymer, Polym. Sci. A, 45, 2032, 2003. 

An oil-based drilling mud can be viscosified with maleated ethylene-propylene elastomers [919]. The elastomers are ethylene-propylene copolymers or ethylene-propylene-diene terpolymers. The maleated elastomers are far more effective oil mud viscosifiers than the organophilic clays used. On the other hand, specific organophilic clays can provide a drilling fluid composition less sensitive to high temperatures [491]. 

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. 

An elastomer consisting of a terpolymer of ethylene, propylene and a diene, e.g., dicyclopentadiene. 

Terpolymerization, the simultaneous polymerization of three monomers, has become increasingly important from the commercial viewpoint. The improvements that are obtained by copolymerizing styrene with acrylonitrile or butadiene have been mentioned previously. The radical terpolymerization of styrene with acrylonitrile and butadiene increases even further the degree of variation in properties that can be built into the final product. Many other commercial uses of terpolymerization exist. In most of these the terpolymer has two of the monomers present in major amounts to obtain the gross properties desired, with the third monomer in a minor amount for modification of a special property. Thus the ethylene-propylene elastomers are terpolymerized with minor amounts of a diene in order to allow the product to be subsquently crosslinked. 

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