Ethylene-propylene monomers rubber

ATBN - amine terminated nitrile rubber X - Flory Huggins interaction parameter CPE - carboxylated polyethylene d - width at half height of the copolymer profile given by Kuhn statistical segment length DMAE - dimethyl amino ethanol r - interfacial tension reduction d - particle size reduction DSC - differential scanning calorimetry EMA - ethylene methyl acrylate copolymer ENR - epoxidized natural rubber EOR - ethylene olefin rubber EPDM - ethylene propylene diene monomer EPM - ethylene propylene monomer rubber EPR - ethylene propylene rubber EPR-g-SA - succinic anhydride grafted ethylene propylene rubber... 

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. 

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. 

FIGURE 11.1S Diffused particles in natural mbber/ethylene-propylene monomer/rranj-polyoctylene rubber (NR-EPM-TOR) blend (a) are much smaller than in blends without TOR (b). (From Chang, Y.-W., Shin, Y.-S., Chun, H and Nab, C., J. Appl. Polym. Set, Ti, 749, 1999.)... 

The crosslinking of ethylene-propylene copolymer rubber (EPR) in the presence of organic peroxides has been investigated by Natta and/or his coworkers (1-3) and others (4,5). Co-agents such as sulfur (3,4) and unsaturated monomers (6), including maleic anhydride (MAH)(3,7) have been utilized in an effort to increase the crosslinking efficiency in the EPR-peroxide system. 

The simplest diene that satisfies this requirement is 1,4-hexadiene, and indeed it has been adopted as the cure site monomer in commercial ethylene-propylene-diene rubber. Because 1,4-hexadiene exists in both trans and cis configurations, significant amounts of work have been devoted to find ways to control the selectivity of the catalysts for one of the isomers over the other. 

The principal use of ethylene-propylene rubbers (ethylene-propylene-diene monomer (EPDM) or ethylene-propylene monomer (EPM) types) is in the manufacture of heat exchanger gaskets. When cured using peroxides, these materials can be used for extended periods at up to 150 °C. Normal conditions of service are high temperatures (<130 °C) and flow or static exposure to aqueous food. 

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. 

Ethylene/propylene co-polymers (usually called EPRs for ethylene-propylene rubbers, or EPMs for ethylene-propylene monomers) are amorphous polyolefins when the propylene content is in the range 30-70%. Despite the typical unreactivity of saturated polyolefins, ethylene-rich EP co-polymers can be made highly elastic by radical cross-linking, but in order to make the rubber vulcanizable , a diene (5-ethylidene-2-norbornene, 1,4-hexadiene, or dicyclopentadiene) is added, which leaves one unreacted double bond available for subsequent cross-linking. These latter materials are called EPDMs (for ethylene-propylene-diene monomers). 

There is a relatively large range of different types of rubbers that are used in different components in the food industry that can get in contact with the food. The most important of these are natural rubber (NR ds-l,4-polyisoprene), nitrile rubber (i.e., acrylonitrile-butadiene copolymer), ethylene-propylene rubber (EPR), rubbers of ethylene-propylene monomer (EPM) and EPDM, SBR, fluorocarbon rubber, silicone rubber, polybutadiene rubber (BR), polychloroprene rubber, and TPE. In addition, there is the use of rubber blends, i.e., blends of NR and N Rr with SBR [19]. 

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

Blending methyl methacrylate-butadiene-styrene copolymer with poly(vinyl chloride) for instance was shown to decelerate the dehydrochlorination (leading to discoloration). The gel content, surface energy, and the spectroscopic characteristics of the blend was altered by the presence of the seccHid polymer [158]. In ethylene-propylene-diene rubber EPDM where the third monomer is ethylene-2-norbomene (NB), the photo-oxidation rate as measured by the accumulation of typical products such as hydroperoxides, varied linearly with the NB content [159]. The same held true for peroxide-crosslinked compounds of the same EPDM except that the linear relationship was found between the relative carbonyl absorbance on photoxidation and the amoiuit of peroxide used to crosslink the material... 

There are many types of commercially available EPDM rubbers. They differ with respect to ethylene/propylene monomer ratio, amount and selection of ter-monomer (unconjugated diene), molecular weight, molecular-weight distribution, viscosity, amount and type of extender oil (if present), processability, and other qualities. 

BR, butyl rubber CB, carbon black CBS, cyclohexyl-2-benzothiazolefulfenamide CNT, carbon nanotube CSPE, chlorosulfonate polyethylene CIP, carbonyl-iron powder EPM, ethylene propylene monomer EPDM, ethylene propylene diene monomer EVA, ethylene-vinyl acetate FSR, fluorosilane rubber GRP, graphite powder HGM, hollow glass microsphere lONP, iron oxide nanoparticle LDH, layered double hydroxide MBT, 2-mercaptobenzothiazol MMT, modified montmorillonite NR, natural rubber PAMAM, polyamidoamine R-EPDM, recycled ethylene propylene diene monomer SR, silicon rubber SBR, styrene-butadiene rubber TBBS, iV-tert-butyl-2-benzothiazolesulfenamide. 

EPDMl, EPDM2 - ethylene-propylene-diene rubber Buna EPG-6470, G-3440 (Bayer Germany monomer composition by weight 71% and 48% of ethylene, 17% and 40% of propylene, 1.2% of ethyUdeno-norbomene, respectively). 

Whdi ethylene is copolymerized with propylene, the amorphous, rubbery material called ethylene propylene rubber PM - from ethylene propylene monomers) results if the ethylene content is high commercial polymers may contain 30 to 50% of ethylene units. In order to obtain a sulfur vul-canisable material, a small percentage of a third monomer (3 to 10% of a diene monomer, for example, ethylidene nor-bornene) is incorporated so as to make a terpolymer, this ter-polymer may be referred to as EPDM. An abbreviation which covers both types of ethylene propylene rubber is EP(D)M usually, all types of this rubber have a propylene content of between 25 and 55% by weight. 

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). 

In consequence ethylene-propylene rubbers were introduced with a small amount (3-8%) of a third, diene, monomer which provided a cross-link site for accelerated sulphur vulcanisation. Such ethylene-propylene-diene monomer ternary copolymers are designated as EPDM rubbers. 

EPDM (Ethylene Propylene Diene Monomer Rubbers) 320 Steam, High-temperature Aqueous Solutions, Inorganic Acids and Organic Acids or bases... 

Process systems handling polymers and resins (e.g., butyl rubber or ethylene-propylene diene monomer rubbers) are often subject to plugging at dead-end locations such as PR valve inlets. In extreme cases, complete blockage of inlet piping and valve nozzle can result. This problem can be eliminated by the application of a flush-seated PR valve, in which dead-end areas are eliminated by placing the valve disc flush with the vessel wall, in the flow pattern of the contents. 

TPEs from blends of rubber and plastics constitute an important category of TPEs. These can be prepared either by the melt mixing of plastics and rubbers in an internal mixer or by solvent casting from a suitable solvent. The commonly used plastics and rubbers include polypropylene (PP), polyethylene (PE), polystyrene (PS), nylon, ethylene propylene diene monomer rubber (EPDM), natural rubber (NR), butyl rubber, nitrile rubber, etc. TPEs from blends of rubbers and plastics have certain typical advantages over the other TPEs. In this case, the required properties can easily be achieved by the proper selection of rubbers and plastics and by the proper change in their ratios. The overall performance of the resultant TPEs can be improved by changing the phase structure and crystallinity of plastics and also by the proper incorporation of suitable fillers, crosslinkers, and interfacial agents. 

---