Acrylonitrile-butadiene rubber properties

Acrylonitrile-butadiene rubber (also called nitrile or nitrile butadiene rubber) was commercially available in 1936 under the name Buna-N. It was obtained by emulsion polymerization of acrylonitrile and butadiene. During World War II, NBR was used to replace natural rubber. After World War II, NBR was still used due to its excellent properties, such as high oil and plasticizer resistance, excellent heat resistance, good adhesion to metallic substrates, and good compatibility with several compounding ingredients. 

Frenkel R., Duchacek V., Kirillova T., and Kuz min E. Thermodynamic and structural properties of acrylonitrile butadiene rubber/polyethylene blends, J. Appl. Polym. Sci., 34, 1301, 1987. 

The polymers described above have been chemically pure, although physically helerodisperse. It is oflen possible lo combine two or more of these monomers in the same molecule to form a copolymer. This process produces still further modification of molecular properties and, in turn, modification of the physical properties of file product. Many commercial polymers are copolymers because of the blending of properties achieved in this way. For example, one of the important new polymers of the past ten years has been the family of copolymers of acrylonitrile, butadiene and styrene, commonly called ABS resins. The production of these materials has grown rapidly in a short period of time because of their combination of dimensional stability and high impact resistance. These properties are related to the impact resistance of acrylonitrile-butadiene rubber and the dimensional stability of polystyrene, which are joined in the same molecule. 

Sequence distribution studies on several types of rubber by 13C-NMR technique have been reported. Some of the more recent reports include silicone rubbers [28-30], SBR [31], acrylonitrile-butadiene rubber (NBR) [32,33], polyurethane [34,35], polyepichlorohydrin [36], ethylene-norbonene [37] and ethylene-propylene rubber [4, 16, 25, 38-44]. The NMR studies on EPDM have been carried out extensively, because it is one of the important parameters, which control the physical properties of the elastomer. For example, ethylene sequence can influence the crystallisation kinetic and melting behaviour of the rubber [38]. 

The elastomeric sealing components of the metering valve are particularly critical. In those valves used with CFC propellants, the elastomeric seals have typically been formed from an acrylonitrile/butadiene rubber, which has been cured with sulfur. These rubber seals may not be fully compatible with HFA propellants hence, alternative elastomeric materials have been used. These materials include peroxide-cured acrylonitrile/ butadiene, ethylene-propylene diene monomer (EPDM), and chloroprene and thermoplastic elastomers (TPE). The elastomeric materials used to form the dynamic seals around the stem and the static gasket seal between the can and valve may differ based on the required properties of the rubber for the specific function of the seal. The most important characteristics of the elastomeric seals... 

Sadhu, S. Bhowmick, A.K. Preparation and properties of nanocomposites based on acrylonitrile-butadiene rubber, styrene-butadiene rubber, and polybutadiene rubber. J. Polym. Sci. B Polym. Phys. 2004, 42 (9), 1573-1585. 

Jung et al. have developed a synthetic elastomer composed of acrylonitrile butadiene rubber copolymer [211, 212]. The properties of the copolymer can be tuned by changing its composition. Reported data for dielectric constant, elastic modulus, and strain relaxation are promising (see Table 1.2). The synthetic elastomer provides some improvement over VHB and some silicone hlms under certain conditions however, the tests were limited to low prestrain (60% radial), where the performance of VHB hlms is poor. 

Table 153 Qualitative summaiy of effect of acrylonitrile content upon properties of acrylonitrile-butadiene rubbers, arrows indicating direction of increase (Hofmaim [6])...

George, J., Joseph, R., Thomas, S., and Varughese, K. T. 1995. High density polyethylene/acrylonitrile butadiene rubber blends Morphology, mechanical properties, and compatibilization. Journal of Applied Polymer Science 57 449-465. 

Tensile Properties of Pure Polymethyl Methacrylate (PMMA) and PMMA-Acrylonitrile Butadiene Rubber (ABN) Blends (Standard Deviations Are Omitted)... 

Cho, H. W., L. R. Hepowit, H. S. Nam et al. 2012. Synthesis and supercapacitive properties of electrodeposited polyaniline composite electrode on acrylonitrile-butadiene rubber as a flexible current collector. Synthetic Metals 162 410 13. 

Polyurethane-based plasticizers can be obtained as a product of hydrolysis of poly-methane scrap as described elsewhere for material from printing rollers.These plasticizers were used to modify acrylonitrile-butadiene rubber.In still another development, diurethane was used in polyurethane elastomers. " Addition of diurethane improved potlife, and mechanical properties. The plasticizer performed better than DOP and it was substantially less migrating than DOP. " ... 

Acrylonitrile-butadiene rubber, NBR, styrene-aciylonitrile rubber, SAN, ethylene-vinyl acetate copolymer, EVA, and acrylic copolymers are helpful modifications of polyvinylchloride that change its processing characteristics and elastomeric properties. Blending with these copolymers helps to reduce the requirement for low molecular weight plasticizers. Ethylene-vinyl acetate copolymer plays a role of high molecular weight plasticizer in production of vinyl hose. This reduces the amount of DOP used in flexible hose applications. Ethylene copolymer is used plasticize PVC that reduces gel. "" Phthalate plasticizers can be eliminated from water based adhesives because of utilization of vinyl acetate ethylene copolymer as a high molecular plasticizer/modifier. " ... 

Before reviewing in detail the fundamental aspects of elastomer blends, it would be appropriate to first review the basic principles of polymer science. Polymers fall into three basic classes plastics, fibers, and elastomers. Elastomers are generally unsaturated (though can be saturated as in the case of ethylene-propylene copolymers or polyisobutylene) and operate above their glass transition temperature (Tg). The International Institute of Synthetic Rubber Producers has prepared a list of abbreviations for all elastomers [3], For example, BR denotes polybutadiene, IRis synthetic polyisoprene, and NBR is acrylonitrile-butadiene rubber (Table 4.1). There are also several definitions that merit discussion. The glass transition temperature (Tg) defines the temperature at which an elastomer undergoes a transition from a rubbery to a glassy state at the molecular level. This transition is due to a cessation of molecular motion as temperature drops. An increase in the Tg, also known as the second-order transition temperature, leads to an increase in compound hysteretic properties, and in tires to an improvement in tire traction... 

A. Laskowska, M. Zaborski, G. Boiteux, O. Gain, A. Marzec, W. Maniukiewicz, Effects of unmodified layered double hydroxides MgAl-LDHs with various structures on the properties of filled carboxylated acrylonitrile-butadiene rubber XNBR, European Polymer Journal, ISSN 0014-3057 60 (November 2014) 172-185. http //dx.doi.0rg/lO.lOl6/j. eurpolymj. 2014.09.013. 

A rather comprehensive study on the relation between curing conditions and product properties of epoxy acrylates, diluted with a reactive diluent and a vinyl-terminated acrylonitrile/butadiene rubber has been carried out by Small et al. 

The natural rubber does not generally exhibit all the desired properties for use in the rubber industry. Thus, it is possible to obtain better mechanical and physical properties at a lower cost by blending natural rubber with synthetic rubbers. Normally, natural rubber is deteriorated by ozone and thermal attacks due to its highly unsaturated backbone, and it also shows low oil and chemical resistances due to its non-polarity. However, these properties can be achieved by blending it with low unsaturated ethylene propylene diene monomer rubber, styrene butadiene rubber, carboxylate styrene butadiene rubber, nitrile butadiene rubber, chloroprene rubber, chlorosulfonated polyethylene rubber, and acrylonitrile butadiene rubber. 

Gatos KG, Karger-Kocsis J (2007) Effect of the aspect ratio of siheate platelets on the mechanical and barrier properties of hydrogenated acrylonitrile butadiene rubber (HNBR)/layeted silicate nanocomposites. Eur Polym J 43 1097-1104... 

Tian M, Su LL, Cai WT, Win S, Chen Q, Fong H, Zhang LQ (2011) Mechanical properties and reinfoFctanent mechanisms of hydrogenated acrylonitrile butadiene rubber composites containing fibrillar silicate nanofibers and short aramid microfibers. J Appl Polym Sci 120 1439-1447... 

Similar to the Nylon/EPR system, the effect of compatibilization on transport properties can be seen in natural rubber/acrylonitrile-butadiene rubber (NR/ NBR) blends compatibilized with poly(ethylene-co-vinyl acetate) (EVAc) [51]. In this case, the penetrant used was benzene. Subsequently, it was noted that the solvent uptake tendency of compatibilized samples was lower, while a greater time lag and minimum values for permeation and diffusion coefficients were exhibited compared to the uncompatibilized blend. The polar CN- end of NBR... 

Blends of polyvinyl chloride (PVC) with acrylonitrile butadiene rubber (NBR) have been used for many years as masterbatches in the rubber industry. Typically the PVC and NBR blend is fluxed at elevated temperatures to achieve optimal properties. Vulcanization curatives can be added to this blend. 

The modified fillers were used in two matrices with different polarity the ethylene-propylene copolymer EPM and hydrogenated acrylonitrile-butadiene rubber HNBR. Elastomers were crosslinked with dicumyl peroxide DCP. The influence of the variously modified fillers on the cross-linking density of the vulcanizates, rheometric and mechanical properties of filled systems were investigated. The ageing studies (thermal, atmospheric and under UV radiations) were conducted. 

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