Terpolymer acrylic elastomers

Polymer Composition. Ethylene—acrylic elastomer terpolymers ate manufactured by the addition copolymerization of ethylene [74-85-1] and methyl acrylate [96-33-3] in the presence of a small amount of an alkenoic acid to provide sites for cross-linking with diamines (4). 

Terpolymers in which the acrylate monomer is the major component are useful as ethylene-acrylate elastomers (trade name Vamac) [Hagman and Crary, 1985]. A small amount of an alkenoic acid is present to introduce sites (C=C) for subsequent crosslinking via reaction with primary diamines (Sec. 9-2d). These elastomers have excellent oil resistance and stability over a wide temperature range (—50 to 200°C). They are superior to nitrile and chloroprene rubbers. Although not superior to silicone and fluorocarbon elastomers, they are less costly uses include automotive (hydraulic system seals, hoses) and wire and cable insulation. 

Arguably the most important amorphous ionomer is sulfonated polystyrene (SPS). Other ionomers include poly(styrene-rfln-methacrylic acid) (SMAA), polyurethanes, siloxanes, butadiene-based elastomers, ethylene-propylene-diene terpolymers, acrylates and methacrylates, polyphosphoesters, polyimides, and many others. ... 

Acrylic resin Acrylonitrilefbutadiene/styrene copolymer Bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite Butadiene/acrylonitrile copolymer EthyleneA/A copolymer Methoxyethyl acrylate Methyl methacrylate butadiene styrene terpolymer Polyethylene elastomer, chlorinated 2-Propenoic acid, 2-methylmethyl ester, polymer with 1,3-butadiene and butyl 2-propenoate impact modifier, PVC rigid EVA/PVC graft polymer impact modifier, recycled polyamides EPDM, maleated impact modifier, thermoplastics Butadiene/acrylonitrile copolymer impact strength modifier PEG-6 trimethylolpropane impact-resistance lights Polyester carbonate resin impact-resistance, lights Polyester carbonate resin impeller... 

When chlorinated polyether is used instead of butadiene, a copolymer called acrylonitrile-chlorinated polyethylene styrene (ACS) is produced. This copolymer has improved flame resistance and weatherability. [See also acrylonitrile-chlorinated styrene (ACS) teropolymer polyethylene styrene (ACS) terpolymer.] Acrylic styrene acrylonitrile (ASA) is produced by grafting an acrylic ester elastomer onto the styreneacrylonitrile segment. This results in better outdoor weathering. ASA is used in products such as gutters, mailboxes, shutters, and outdoor furniture. (See also acrylic styrene acrylonitrile.) Modifications are also available that enhance adhesion of electroplated coating to the ABS plastic. ABS is the most widely used material for electroplated plastic parts. 

The polymerization process yields a random, amorphous terpolymer or a random, amorphous dipolymer (no cure-site monomer). The pol5uner backbone is fully saturated, making it highly resistant to ozone attack even in the absence of antiozonant additives. The fluid resistance and low temperature properties of ethylene-acrylic elastomers are largely a function of the methyl acrylate to ethylene ratio. As the methyl acrylate level increases, the polymer becomes more polar and has better fluid resistance to aliphatic hydrocarbon oils. Also, as the methyl acrylate level increases, the glass-transition temperature (Tg) of the polymer increases slightly. There is a trade-off between oil resistance and low temperature performance. 

Commercial Forms. Four different base polsrmers of Vamac ethylene-acrylic elastomers are commercially available (Table 1). Until 1990, existing grades of ethylene-acrylic elastomers were based on a single-gum polymer, Vamac G, defined as a terpolymer of 55% methyl acrylate, ethylene, and a cure-site monomer (6). In 1991, a higher methyl acrylate terpolymer, Vamac GLS, was introduced. The composition of this polymer was specifically chosen because it significantly increased the oil resistance of the polymer while minimizing the loss in low temperature flexibility (7). 

Several new products are imder development (10), including a higher viscosity terpolymer. These new products, when commercialized, will expand the serviceability of the ethylene-acrylic elastomers and also improve their process-ability. 

The new elastomers are particularly relevant to the automotive industry because they offer better properties - particularly heat, oil and fuel resistance - than the established materials such as natural and synthetic rubber and plasticized PVC. Among the most important types are PUR elastomers, PBT block copolymers, EPDM olefinic terpolymers and ethylene-acrylic elastomers. Typical applications are the traditional rubbery ones of gaskets, seals, gaiters and cable covers, but set in the aggressive underbonnet environment of today s performance vehicles. Beyond this, however, there are examples where these materials are sufficiently versatile to have been selected, sometimes with reinforcement, as engineering components in their own right. 

AEM Ethylene acrylic Elastomer Copolymer of ethylene, methyl acrylate (peroxide curable). Terpolymer contains cure site monomer Weather, ozone, hydrocarbon lubricants/greases, hydraulic fluids Aromatic hydrocarbons, esters, gasoline, ketones... 

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. 

Many other crosslinking reactions are used in commercial applications. A variety of halogen-containing elastomers are crosslinked by heating with a basic oxide (e.g., MgO or ZnO) and a primary diamine [Labana, 1986 Schmiegel, 1979]. This includes poly(epichlorohydrin) (Sec. 7-2b-6) various co- and terpolymers of fluorinated monomers such as vinylidene fluoride, hexafluoropropene, perfluoro(methyl vinyl ether), and tetrafluoroethylene (Sec. 6-8e) and terpolymers of alkyl acrylate, acrylonitrile, and 2-chloroethyl vinyl ether (Sec. 6-8e). 

Acrylic-styrene-acrylonitrile terpolymers, ASA, are produced by simultaneous polymerization of styrene and acrylonitrile monomers in the presence of an acrylic rubber (polybutylacrylate). Thus, the material has a two-phase strucmre similar to ABS. However the elastomer phase in ASA is saturated and thus significantly more resistant to oxidative degradation. ASA is used in applications requiring good weatherability, mostly with PVC. The blends are primarily extruded for exterior trims and window profiles applications. 

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. 

Nowadays commercial mixtures of bitumens with uncured synthetic elastomers are produced, e.g. ethylene-propylene-diene terpolymers (EPDM), styrene-butadiene sequence copolymers (SBS), and ethylene-acrylic ester-acrylic acid terpolymers (AECM). Mixtures with some thermoplastics are also commercial products, e.g. polyethylene (PE), ethylene-propylene copolymers (EPM), alpha-olefinic copolymers, atactic polypropylene (aPP), and ethylene-vinyl acetate copolymers (EVA). 

Further, the effect of the reinforcement of carbon nanotubes on the properties of the recycled PET/PEN blends has been investigated [83]. Two types of functional elastomers, a terpolymer of ethylene ethyl acrylate-maleic anhydride and a terpolymer of ethylene-methyl acrylate-glycidyl methacrylate, have been used to ensure the miscibility between poly(ethylene terephthalate) and poly(ethylene naphthalate) during the preparation of the blends. 

Elastomers which have been found to effectively toughen epoxies include acrylic, carboxyterminated butadiene acrylonitrile, polyurethane, certain terpolymers as well as polysiloxane. Addition of two mbbers with different solubility parameters to epoxy can yield a phase separated material with particles oftwo different sizes. 

---