Terpolymer ethylene propylene

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). 

Occasionally polymers are used to increase the viscosity of oil-base and synthetic-base muds. The polymers for this use are typically sulfonated polystyrenes or ethylene—propylene terpolymers (EPDM) (54,55). Such polymers are usually used in conjunction with an organopbilic clay. 

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. 

Whilst the ASA materials are of European origin, the AES polymers have been developed in Japan and the US. The rubber used is an ethylene-propylene terpolymer rubber of the EPDM type (see Chapter 11) which has a small amount of a diene monomer in the polymerisation recipe. The residual double bonds that exist in the polymer are important in enabling grafting with styrene and acrylonitrile. The blends are claimed to exhibit very good weathering resistance but to be otherwise similar to ABS. 

Standard butyl rubber, which is a copolymer of isobutylene with about 2% of isoprene vulcanises in the same manner as natural rubber but, as it only contains a small proportion of polyisoprene, the cross-link percentage is much reduced. It is therefore not possible to make ebonite from a butyl rubber. The same vulcanisation chemistry, with some modifications, applies to ethylene-propylene terpolymers and brominated butyl rubber. 

The preferred systematic abbreviation for ethylene-propylene terpolymer, also designated EPT. The use of the term EPR for a copolymer of ethylene and propylene, and the use of EPT for a terpolymer of these monomers with a small amount of a diene to provide double bonds is common but is not recommended. Epichlorohydrin... 

Acrylic rubber Chlorinated polyethylene Chlorosulphonated polyethylene Ethylene-propylene copolymer Ethylene-propylene terpolymer Fluorocarbon rubbers (certain grades)... 

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... 

The effect of nucleophilic dienes on the copolymerization of ethylene and propylene has been reported by Gladding, Fisher and Collette (88). Table 8 shows that 1.4-hexadiene decreased the tendency for propylene to enter into the ethylene-propylene terpolymer, produced by a triisobutyl aluminum-vanadium oxychloride catalyst. 

Membranes comprising silicone rubber coated onto polyimides, polyacrylonitrile or other microporous supports membranes are widely used [12,27]. Other rubbers such as ethylene-propylene terpolymers have been reported to have good properties also [28]. Polyamide-polyether block copolymers have also been used for pervaporation of some polar VOCs [29,30]... 

EPDM-g-PMMA was produced through ATRP with CuBr/bipyridine [80]. The graft copolymer, which had an ethylene-propylene terpolymer (EPDM) backbone and PMMA branches, was prepared from brominated EPDM that was produced with NBS to introduce allylbromine moiety on the backbone. Resulting EPDM-g-PMMA graft copolymers were characterized by solvent extraction, infrared (IR), and NMR techniques. 

NATURAL RUBBER(Polyisoprene) POLYBUTADIENE STYRENE-BUTADIENE RUBBER ETHYLENE/PROPYLENE TERPOLYMER... 

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... 

TM for a low-cost, high-performance ethylene-propylene terpolymer. 

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

The data thus far have shown that S-PS can be plasticized effectively with respect to backbone and ionic domain plasticizers. By appropriate choice of the plasticizer type either the PS backbone or the ionic domains can be plasticized preferentially. By appropriate control of the metal sulfonate content and the polarity of the plasticizer used, flexible S-PS compositions possessing useful tensile properties are feasible. While this approach has substantial merit, it is apparent that simply increasing the level of a phthalate plasticizer to improve melt flow results in a substantial decrease in useful tensile properties. It would be desirable to use a given level of backbone plasticizer and adjust the melt flow of the entire composition by independently plasticizing the ionic domains. One approach to achieve this objective has been described in the plasticization of ionic groups in metal-sulfonated ethylene propylene terpolymers (9). In those systems, the incorporation of metal carboxylates as plasticizers can improve both flow behavior and tensile properties. It is of interest to determine if this class of plasticizers can be combined with the phthalate plasticizers used for the S-PS backbone to provide an improved balance of flow behavior and tensile properties for S-PS s. 

Altenau,A.G., Headley,L.M., Jones,C.O., Ransaw,H.C. Termonomer analysis in ethylene propylene terpolymers. Anal. Chem. 42,1280-1282 (1970). 

Hank, R. Determination of double bonds in ethylene propylene terpolymer rubbers. Rubber Chem. Technol. 40,936-946 (1967). 

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