Blend acrylonitrile-butadiene rubber

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. 

Pandey et al. have used ultrasonic velocity measurement to study compatibility of EPDM and acrylonitrile-butadiene rubber (NBR) blends at various blend ratios and in the presence of compa-tibilizers, namely chloro-sulfonated polyethylene (CSM) and chlorinated polyethylene (CM) [22]. They used an ultrasonic interferometer to measure sound velocity in solutions of the mbbers and then-blends. A plot of ultrasonic velocity versus composition of the blends is given in Eigure 11.1. Whereas the solution of the neat blends exhibits a wavy curve (with rise and fall), the curves for blends with compatibihzers (CSM and CM) are hnear. They resemble the curves for free energy change versus composition, where sinusoidal curves in the middle represent immiscibility and upper and lower curves stand for miscibihty. Similar curves are obtained for solutions containing 2 and 5 wt% of the blends. These results were confirmed by measurements with atomic force microscopy (AEM) and dynamic mechanical analysis as shown in Eigures 11.2 and 11.3. Substantial earher work on binary and ternary blends, particularly using EPDM and nitrile mbber, has been reported. 

Naskar, M., Debnath, S.C., and Basu, D.K. Effect of Bis (Diisopropyl) Thiophosphoryl Disulfide on the Co-Vulcanization of Carboxyhc Acrylonitrile Butadiene Rubber and Ethylene Propylene Diene Rubber Blends. Rubber Chem. Technol. 75(3), 309-322, July/August 2002. 

This method involves the mechanical blending of styrene-acrylonitrile copolymers and acrylonitrile-butadiene rubbers. Many products are possible depending on the composition of each copolymer and the relative amounts employed. 

In an example 70 parts (70 30 styrene acrylonitrile-copolymer) gets blended with 40 parts (35 65 acrylonitrile butadiene rubber). After it gets blended, the coagulation of the polymer is brought about by adding an acid or salt. 

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. 

Solid-state 13C NMR has been used to identify elastomers in binary blends of chloroprene (CR) and NR, CR and CSM, NR and CSM, and SBR and acrylonitrile-butadiene rubber (NBR). The type of NBR can be determined by identifying the sequences of acrylonitrile and butadiene. The tertiary blend of NR/SBR/BR was also studied [49]. High-temperature 13C solid-state NMR identified ethylene-propylene diene terpolymer (EPDM) and fluoro and nitrile rubbers [50]. 

Vlassopoulos et al. (1998) examined the gelation of three epoxy-rubber thermoset blends (based on TGDDM/DDS/(acrylonitrile/butadiene rubber/methacrylic acid copolymer) of the same chemistry but different pre-cure treatments. The pre-treatments used heat and catalysts to promote epoxy-carboxyl reactions, and there was some evidence of a decrease in gelation time and an effect on pre-gel rheology with these treatments. 

Examples of such compatibilized systems that have been studied include EPDM/PMMA blends compatibilized with EPDM- -MMA, polypropylene/polyethylene blends with EPM or EPDM, polystyrene/nylon-6 blends with polystyrene/nylon-6 block copolymer, and poly(styrene-co-acrylonitrile)/poly(styrene-co-butadiene) blends with butadiene rubber/PMMA block copolymer. 

Spadaro, G., Dispenza, G., Me Grail, R, and Valenza, A. 2004. Submicron structured polymethyl methacrylate/acrylonitrile-butadiene rubber blends obtained via gamma radiation induced in situ polymerization. Advances in Polymer Technology 23(3) 211-221. 

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. 

Raj et al. °" have compared the efficiency of microwave and e-beam irradiations to stabilize the interface of various partially miscible or nonmiscible blends polystyrene (PS)/polymethyl methacrylate (PMMA), polyvinyl chloride (PVC)/ethylene vinyl acetate (EVA), PP/acrylonitrile butadiene rubber (NBR), and polyvinyl chloride (PVC)/poly(styrene acrylonitrile) (SAN). For this purpose, they used positron annihilation lifetime measurements, and they considered particularly a hydrodynamic interaction parameter a. This... 

Spadaro et al. - polymerized methyl methacrylate (MMA) monomers in the presence of acrylonitrile-butadiene rubber by y-irradiation at a temperature of 70°C. For pure MMA, a total dose of 4 kGy is enough to complete polymerization and further irradiation (6.3 kGy) leads to a degradation of PMMA macromolecules. On the contrary, for PMMA/ABN blends, a higher dose... 

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

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... 

Chowdhury, R. Electron-beam-induced crosslinking of natural lubber/acrylonitrile-butadiene rubber latex blends in the presence of ethoxylated pentaerythritol tetraaciylate used as a crosslinking promoter. J. Appl. Polym. Sci. 103, 1206-1214 (2007)... 

Ishida et reported melt blending of PLA with four types of common rubbers, ethylene-propylene copolymer (EPM), ethylene-acrylic rubber (EAM), acrylonitrile-butadiene rubber (NBR) and isoprene rubber (IR), to toughen PLA. All blends showed separated phase morphology where the elastomer phase was homogeneously distributed in the form of small droplets in the continuous PLA phase. Izod impact testing showed that toughening was achieved only when PLA was blended with NBR, which showed the smallest rubber particle size in the blends. In addition, the interfacial tension between both phases, PLA and NBR, was the lowest. 

Although an ethylene vinyl acetate copolymer was immiscible in NR blends, addition of a 6 phr ethylene vinyl acetate block copolymer enabled compatibilization of heterogeneous NR/acrylonitrile butadiene rubber blends. These blends increased the tensile strength, the elongation at break and tear strength due to an increase in the interfacial adhesion between the blended components by increasing the rigidity of the matrix in the presence of the ethylene vinyl acetate copolymers. ... 

Kalf et al. studied the effect of grafting cellulose acetate and methylmethacrylate as compatibilizers on acrylonitrile butadiene rubber (NBR) and styrene-butadiene rubber (SBR) blends. Morphology studies of the samples show an improvement in interfacial adhesion between the NBR and SBR phases in the presence of the prepared compatibilizing agents. The authors also reported the samples with grafted compatibilizers showed superior crosslink density and thermal stability, as compared to the blends without graft copolymers. ... 

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. 

The blending of natural rubber with thermoplastics, and other rubbers have been reported in the literature. Thus, blends of NR with (i) ultra-low density polyethylene, (ii) styrene-butadiene rubber (SBR), (iii) epoxidized natural rubber, (iv) acrylonitrile butadiene rubber," (v) chloroprene rubber" and (vi) dichlorocarbene modified styrene-butadiene rubber (DCSBR)" have been prepared, characterized and reported in the literature. 

Acrylonitrile butadiene rubber is susceptible to ozone attack, and therefore suitable anti-ozonants and/or waxes need to be added. Acrylonitrile butadiene rubber /EPDM blends (at 70/30 or 80/20 ratio) bave a better ozone resistance than NBR alone. 

The products obtained by this method are mechanical blends of styrene-acrylonitrile copolymers and acrylonitrile-butadiene rubbers. The preferred method of preparation is by blending latices of the two copolymers and coagulating the mixture. A wide range of products is possible, depending on the composition of each copolymer and the relative amounts of each employed. A typical blend would consist of the following (solids) ... 

An alternative method of preparing a blend of the two copolymers is by mixing the solids on a two-roll mill. In this case, a non-cross-linked acrylonitrile-butadiene rubber may be used as starting material. The rubber is firstly cross-linked by milling with a peroxide and then the styrene-acrylonitrile copolymer is added. 

Rubbers and elastomeric products for practical applications are usually blends of different elastomer types that develop specific domain morphologies at the microscale, and, therefore, they are a part of this chapter. The most common representatives of the ruhher family are natural ruhher (NR) and the synthetic polyhutadiene ruhher (PB). There are various copolymers of butadiene with styrene (styrene butadiene rubber, SBR) or acrylonitrile (acrylonitrile-butadiene rubber, NBR). Several elastomers have been developed for special purposes, such as EVA (ethylene vinyl acetate copolymer), PU (polyurethane), EPDM (ethylene propylene terpolymer), and siUcone rubber. 

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