Nitrile Butadiene Rubber Blends Research Articles

Investigation of the low‐temperature properties and oil resistance of peroxide‐cured epichlorohydrin rubber and nitrile butadiene rubber blends

Investigation of the low‐temperature properties and oil resistance of peroxide‐cured epichlorohydrin rubber and nitrile butadiene rubber blends

Partial Miscibility and Concentration Distribution of Two-Phase Blends of Crosslinked NBR and PVC

We found that the blends of nitrile butadiene rubber (NBR) and polyvinyl chloride (PVC) exhibited lower critical solution temperature (LCST)-type phase behavior in which a single-phase blend tends to phase separate at elevated temperatures when the acrylonitrile content of NBR was 29.0%. The tan δ peaks, which originated from the glass transitions of the component polymers measured by dynamic mechanical analysis (DMA), were largely shifted and broader in the blends when the blends were melted in the two-phase region of the LCST-type phase diagram, suggesting that NBR and PVC are partially miscible in the two-phase structure. The TEM-EDS elemental mapping analysis using a dual silicon drift detector revealed that each component polymer existed in the partner polymer-rich phase, and the PVC-rich domains consisted of aggregated small PVC particles the size of several ten nanometers. The partial miscibility of the blends was explained by the lever rule for the concentration distribution in the two-phase region of the LCST-type phase diagram.

Nanokaolin reinforced carboxylated nitrile butadiene rubber/polyurethane blend-based latex with enhanced tensile properties and chemical resistance

The demand for gloves (e.g., disposable gloves, medical gloves) is increasing due to the Coronavirus disease 2019 (COVID-19) pandemic. Stability in the supply chain in the glove industry is important, and thus strategies are used to solve the problem of the shortage of nitrile gloves. The blending of nitrile butadiene rubber (NBR) with polyurethane (PU) and the use of the nanocomposite concept is among the feasible approaches. The present study aims to investigate the effects of nanokaolin (NK) on the tensile and chemical properties of carboxylated nitrile butadiene rubber (NBR)/polyurethane (PU) latex blends. Three different loadings of NK (10, 20, and 30 parts per hundred rubber) were added to the NBR/PU (at a blending ratio of 85/15). The zeta potential showed that all the NBR compounds exhibit good colloidal stability. The incorporation of NK increased the crosslink density and tensile strength of the NBR/PU latex blends. The highest tensile strength was achieved when the NK loading was 20 phr. All the NBR blends and nanocomposites (NBR/PU-based) possess tensile properties that fulfill the requirements for glove application. The chemical resistance of NBR compounds was increased by the incorporation of NK due to the higher crosslink density and barrier properties contributed by the NK.

Investigation on the mechanical properties and oil resistance of sulfur cured nitrile rubber/hydrogenated nitrile butadiene rubber blends

AbstractNitrile rubber (NBR)/hydrogenated nitrile butadiene rubber (HNBR) blends with various ratios were compounded with internal mixer and two‐roll open mill. Mechanical properties and low‐temperature performance (TR10) of the NBR/HNBR blends after aging under different conditions were investigated. Furthermore, equilibrium swelling test and moving die rheometer (MDR) test were used to systematically investigate the effects of HNBR dosage on the crosslink densities and curing behaviors. Vulcanization torque and crosslink densities decreased with an increase in HNBR content. The crosslink density of pure HNBR is higher than that of pure NBR, which is related to the macromolecular structures of the rubber. Compression sets of the NBR/HNBR vulcanizates were correlated with HNBR dosage indicating a linear relationship. Low‐temperature performance of the NBR/HNBR blends was improved after being aged in the synthetic hydrocarbon hydraulic oils (SH‐1 and SH‐2). This work shows that the low‐temperature performance and oil resistance could be better balanced by blending NBR with HNBR, while the mechanical properties maintain relatively high level.

Mechanical behavior of silicon carbide filled SBR/NBR blends

Generally, SBR and NBR are widely used in industrial as well as in automobile applications. The main aim of this research is to determine the mechanical properties and their behavior of SBR (Styrene Butadiene Rubber) and NBR (Nitrile Butadiene Rubber) blends mixed with silicon carbide (SiC – as filler) in different compositions. SBR and NBR sheets, and SiC powder are bought and the rubbers are mixed to form blends in order to enhance the properties. Mechanical properties such as tensile, tear, abrasion and resilience tests were conducted according to ASTM standards. Also, hardness was also measured, and properties of all samples were compared. Graphs were drawn to compare the results obtained. Enhancement in properties were obtained and noted.

Tensile and oil resistance properties of chloroprene added in epoxidized natural rubber, nitrile butadiene rubber, and poly vinyl chloride blends

In order to enhance the oil resistance of natural rubber (NR) and Epoxidized natural rubber (ENR), this research was investigated the effect of chloroprene addition as compatibilizer into natural rubber (NR), nitrile butadiene rubber (NBR), and poly vinyl chlorides (PVC) blends. The study aims to examine the effect of CR addition into NR and ENR blends with NBR, PVC on physical mechanical, tensile and oil resistance properties of the thermoplastic elastomer / blends. ENR was prepared using natural rubber latex (30% DRC), 1 M formic acid, 1M acetic acid glacial at temperature 70-80°C for about 6 hours. The CR was added 0; 2,5; 5; 7,5; 10 phr into both NR/NBR/PVC and ENR/NBR/PVC blends. The mastication, blending and rubber compounding were conducted based on the ASTM procedures. The results show that at similar blend ratio composition of CR/NBR/PVC, ENR possess slight higher hardness values and better oil resistance compared to NR blends. However, tensile strength, elongation at break, and modulus of NR blends is not significantly different from ENR. In terms of change mass and the changes value of tensile strength and hardness after oil immersion, ENR blends that has oxirane group has better properties rather than NR blends. The CR addition could present a chlorine atom that restrict oil diffusion and oil absorption into the blends, thus it might lower the change mass and enhance the oil resistance. The CR loading also give positive trends in tensile strength, elongation at break for both NR and ENR blends, but an adverse effect on the modulus 100% elongation. In addition, the higher CR added, the smaller changes on tensile strength and hardness after oil immersion in both NR and ENR blends. It could be inferred that CR addition is able to improve compatibility and process-ability of the NBR, ENR, NR, and PVC blends using a proper plasticizer.

Highly reinforced blends of nitrile butadiene rubber and in-situ synthesized polyurethane–urea

A simplified reactive blending method is investigated to blend effectively the nitrile butadiene rubber (NBR) and in-situ synthesized polyurethane–urea (PUU). The in-situ synthesis of PUU via the prepolymer route was realized in presence of NBR in an internal mixer at a reactive blending temperature of 100°C that was determined from the chemo-rheological analysis of PUU reactive premix of 4,4′-diphenylmethane diisocyanate-terminated prepolymer and 1,3-phenylene diamine. The 1H NMR spectroscopic analysis showed high conversion (∼87±3%) of amino groups of 1,3-phenylene diamine during rapid in-situ addition polymerization with isocyanate groups of prepolymer. The peroxide-cured NBR/PUU blend vulcanizates exhibited remarkable improvements in cure characteristics, mechanical and dynamic-mechanical properties. The dynamic-mechanical analysis of blend vulcanizates demonstrated a concentration-dependent higher storage modulus (E′) and a lower loss factor (tanδ) in a stable rubbery plateau region extending up to 180°C. The improvement in performance characteristics of blend vulcanizates was attributed to the strong interfacial adhesion developed during the reactive blending process and was verified by SEM and energy filtered TEM measurements.

TG–MS analysis of nitrile butadiene rubber blends (NBR/PVC)

Blends of nitrile butadiene rubber (NBR) with polyvinyl chloride (PVC) are widely used in products such as hoses and seals. As part of a project that uses NBR/PVC blends for manufacturing forest fire hoses, blends of NBR/PVC with various inorganic fillers, such as Mg(OH) 2, china clay (organic modified kaolin) and nano clay (organic modified bentonite) were studied by TG–MS. No significant changes were observed to the type of the polymers’ decomposition products, compared to that of NBR/PVC blend without additives. The most remarkable change was the absence of HCl from decomposition products in the presence of the Mg(OH) 2 additive.

Effect of the filler characteristics on the miscibility of styrene‐butadiene rubber and nitrile‐butadiene rubber blends

AbstractStyrene‐butadiene rubber (SBR) and nitrile‐butadiene rubber (NBR) blends are immiscible. Fillers can be used as compatibilizers. The SBR + NBR blends reinforced with a mesoporous silica and a precipitated silica are characterized by studying their miscibility by the determination of rubber bound, their changes in heat capacity at each glass transition temperature, and their mechanical performance. NBR is preferentially located at the silica surface improving its dispersion. Larger rubber + filler as well as SBR + NBR interphases are obtained for the blends reinforced with the mesoporous silica, whose high surface area and organized porous structure allow a better polymer + filler interaction. The reinforced blends present higher strength at break than each reinforced polymer alone. The best performance is attained for blends reinforced with mesoporous silica. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

Nonequilibrium nanoblend membranes for the pervaporation of benzene/cyclohexane mixtures

AbstractImmiscible blends of polymers were cast from solution, and the rate of evaporation was controlled relative to the rate of phase separation to produce different morphologies; upon crosslinking, stable nonequilibrium nanoblends were realized. This process of forced assembly produced useful membrane materials that could be designed for solubility selectivity with the group contribution methodology. Crosslinked ternary blends of nitrile butadiene rubber (NBR), poly(methyl methacrylate) (PMMA), and a tercopolymer of ethylene oxide/epichlorohydrin/allyl glycidyl ether (Hydrin) were examined for use in the separation of benzene from cyclohexane by pervaporation. For a 50 : 50 wt % benzene/cyclohexane feed, blend 811 (containing 80 wt % NBR, 10 wt % Hydrin, and 10 wt % PMMA) gave a separation factor of 7.3 and a normalized flux of 28 kg μm/m2 h; such a performance is unmatched in the literature, with the flux being very high for the reported separation factor. Among the samples tested, the flux of the membrane increased as the amount of NBR in the ternary blend decreased; however, the separation factor was not largely affected. Blended samples showed no sign of deformation after 48 h at the operating temperature as compared to pure NBR, which did show evidence of creep. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Radiation Vulcanization of Nitrile Butadiene Rubber/Butadiene Rubber Blends

Blends of nitrile butadiene rubber (NBR) with butadiene rubber (BR) with varying ratios have been prepared. Vulcanization of prepared blends has been induced by ionizing radiation of gamma rays with varying dose up to 250 kGy. Physical properties, namely soluble fraction and swelling number have been followed up using toluene as a solvent. Mechanical properties, namely tensile strength, tensile modulus at 100% elongation and elongation at break have been followed up as a function of irradiation dose, as well as blend composition. Thermal stability of blends was studied by TGA. The result indicated that the addition of NBR has improved the properties of NBR/BR blends. Also, NBR/BR blend is thermally stable than BR alone.

Ultrasonic investigation of brittle-ductile transition in high-density polyethylene and nitrile-butadiene rubber blends

It was reported by Hourston and Hughes [1] and Kuleznev et al. [2] that compatibility of polymer blends could be examined via ultrasonic velocity measurement. Singh et al. [3] and Singh and Singh [4] measured the ultrasonic velocity of compatible, semicompatible and incompatible polymeric blends in dilute solutions. They found that the plot of the ultrasonic velocity versus composition showed linearly for a compatible polymer blend, while it exhibited an inverted s-type curve for an incompatible polymer blend. Their experimental results also indicated that the plot of the ultrasonic velocity versus composition lay in between the two extremes for a semicompatible polymer blend, i.e., between stype and a straight line. Furthermore, Kuleznev et al. [2] and Singh and Singh [5] extended the ultrasonic velocity measurement to polymeric blends in the solid state. They demonstrated that the ultrasonic technique could indicate the extent of the compatibility between polymers. In the past decade, investigations [6, 7] of polymer compatibility by ultrasonic measurement have again attracted attention, and the method is regarded as suitable for determining compatibility. Recent investigation [8] of the blends of highdensity polyethylene (HDPE) and nitrile±butadiene rubber (NBR), the latter containing 24% by weight of acrylonitrile, revealed that introducing a small amount of NBR into HDPE could greatly elevate the matrix toughness. The NBRs are derived from the copolymerization of butadiene and acrylonitrile, and the strong polarity of acrylonitrile is able to result in incompatibility of HDPE and NBR. To determine why NBR can still toughen HDPE, we prepared a series of HDPE=NBR blends in which the NBRs contained different acrylonitrile contents. We examined the compatibility of various NBRs with HDPE by the ultrasonic velocity measurement. From our experimental data, we found that the ultrasonic velocity measurement was also useful for characterizing the ductile±brittle transition in polymer blends. HDPE is a commercial product; its melting index is 0.5 and the density is 0.955. All NBRs are commercial products that contain 18, 20, 24, 26, 30, 35 and 40% by weight of acrylonitrile and are respectively labeled as NBR18, NBR20, NBR24, NBR26, NBR30, NBR35 and NBR40. The NBRs were plasticated in a double roller mixer at ambient temperature for 10 min, then were blended with HDPE at 155±158 8C for 10 min. Prepared blends were molded into plates 4 mm thick at 180 8C under hot-pressure, then were processed into specimens for the Izod impact test and ultrasonic velocity measurement. The compressional ultrasonic velocities of the blends were performed by the same manner of Singh and Singh's [4]. The frequency was 2.6 MHz. The fracture morphology was observed using scanning electron microscopy (SEM; Hitachi X-650). Fig. 1 shows the relationship plots of the Izod impact strength versus acrylonitrile content of NBRs at a certain constant blend composition. It is obvious that a ductile±brittle transition appears as the acrylonitrile content is in the range of 26% to 30% by weight. This transition can be observed in the same variation range of acrylonitrile content despite the variation of the blend composition. That the ductile±brittle transition is not related to the blend composition may be because of the dominant role of the compatible extent of every kind of NBR with HDPE. Because NBRs consist of butadiene and acrylonitrile in different compositions, compatibility of HDPE and various NBRs should respond to the variation of acrylonitrile content in NBRs due to its strong polarity and incompatibility with HDPE. According to the experimental data of Jorgensen et al. [9], by investigating the phase structure of various NBRs, the NBRs were found to have two transitions if the acrylonitrile content in NBR was less than about 30% by weight. The one in the lowtemperature region was assigned to butadiene-rich NBR phase, while the other one in the hightemperature region was dedicated to acrylonitrilerich phase. Both phases could be separated by the