Polyacrylate elastomers properties

I. Kubota and H. Kanno, Improved Low-Temperature Properties Polyacrylate Elastomers, 160th Meeting, Rubber Division, ACS, Cleveland, October 16-19, 2001. 

Ozonc-rcsjstant elastomers which have no unsaturation are an exceUent choice when their physical properties suit the appHcation, for example, polyacrylates, polysulfides, siHcones, polyesters, and chlorosulfonated polyethylene (38). Such polymers are also used where high ozone concentrations are encountered. Elastomers with pendant, but not backbone, unsaturation are likewise ozone-resistant. Elastomers of this type are the ethylene—propylene—diene (EPDM) mbbers, which possess a weathering resistance that is not dependent on environmentally sensitive stabilizers. Other elastomers, such as butyl mbber (HR) with low double-bond content, are fairly resistant to ozone. As unsaturation increases, ozone resistance decreases. Chloroprene mbber (CR) is also quite ozone-resistant. 

Mechanical Properties of Thermoplastic Elastomers Based on Acrylate Rubber-Fluorocarbon Rubber-Polyacrylate Monomer... 

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. 

Uses Monomer for solv.-resist. elastomers, polyacrylate rubbers, UV-curable reactive diluent, soft contact lenses, PVC impact modifier, fabric coatings, barrier coatings for polyethylene, textile coatings Properties APHA 50 color m.w. 130.15 sp.gr. 1.012 (20/20 C) flash pt. 82 C 98.5% act. 

To achieve good toughness, required for many applications, impact modifiers are added to PVC. Chlorinated polyethylenes, ethylene-vinyl acetate copolymers, styrene-methyl methacrylate grafted elastomers, vinyl rubbers, and polyacrylates are the most frequently used (316). These polymers are blended together with other additives. Blending conditions are extraordinary important for morphology control and consequently for final properties of the blends. 

NR and plastic blends have been reported for the preparation of thermoplastic NR blended systems. Many types of plastics have been blended with NR, such as polyethylene, polypropylene, polystyrene, " polyacrylates or polyacrylic acid, and poly(methyl methacrylate). These thermoplastic NRs provide new materials with different properties that range from a soft elastomer to a semi-rigid NR plastic for various industrial applications.In addition, NR can improve the toughness of brittle thermoplastic materials. The NR and thermoplastic blends express greater ductility and impact strength at low temperatures. The requirements for certain mechanical and physical specifications can be achieved by optimizing the blended compositions and selecting the most suitable thermoplastics. 

It is necessary for the dispersed rubbery substance to have a Tg value lower than the temperature at which the high-impact material is to be used. Many elastomers will satisfy this condition they are butyl rubber, polybutadiene, SBR, BAN, ethylene-propene elastomer, polychloroprene, EVA, polyisoprene, polyacrylates, PIB, and chlorinated polyethylene (CPE) elastomers. However, they are not all useful for specific blends such as PVC-based blends because they do not fulfill the other necessary properties. 

Nipol AR12, AR14, and AR22, special grades of polyacrylate, have been developed to provide properties similar to or better than an AEM elastomer, although they are not chemically equivalent [12-14]. 

Elastomers containing polyepichlorohydrin, also known as ECO, CO, or GECO according to ASTM, offer an excellent balance of properties, combining certain desired dynamic properties of namral mbber (NR), with much of the fuel, oil, and chemical resistance of other specialty elastomers such as nitrile (NBR), polyacrylate (ACM), and neoprene (CR) mbbers. The combination of the basic properties of oil, fuel, heat, low-temperature flexibility, and ozone resistance imparted by the saturated main chain and the chlorine groups, coupled with low permeability, makes polyepichlorohydrin a very useful elastomer for automotive applications. Specific applications include fuel hoses, emission tubing, air ducts, seals, and diaphragms. 

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