Physical-mechanical behavior of nitrile rubber-synthetic mica nanocomposites (original) (raw)
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Polímeros, 2010
Nanocomposites constituted by nitrile rubber matrix and Cloisite 15A (OC15A) as the organoclay were prepared by melt blending and cured with the m-phenylene-bis-maleimide (BMI)/dicumyl peroxide (DCP) system. The effect of mixing parameters on the clay dispersion was evaluated, including mixing temperature and time, and rotor speed of the internal mixer. The organoclay effectively accelerated the vulcanization reaction of NBR, which was attributed to the presence of the alkylammonium salt as the intercalant. All nanocomposites displayed improved tensile properties indicating a good reinforcing action of the clay. Also, the creep compliance was substantially reduced with the incorporation of the clay. X-ray diffraction studies showed the presence of intercalated and deintercalated clay population. The mixing parameters did not have an important effect on clay dispersion and properties of NBR-clay nanocomposites, except for the creep behavior.
Journal of Polymer Research
The morphological, mechanical, and thermal stability of Nitrile rubber nanocomposites reinforced with fillers such as layered silicate (LS), calcium phosphate (CP) and titanium dioxide (TO) having different particle size and chemical nature were analyzed. The results revealed that the filler geometry played an important role on the mechanical and thermal stability of the composites. Calcium phosphate and titanium dioxide filled systems showed comparatively better mechanical and thermal stability compared to neat rubber. The activation energy needed for the thermal degradation was found to be higher for layered silicate filled system. DSC (Differential Scanning Calorimetry) analysis revealed a change in the Tg values as a result of the addition of fillers. This was more prominent with the case of layered silicate filler addition in comparison with calcium phosphate and titanium dioxide. The heat capacity values of the nanocomposites were carefully evaluated. The (∆Cp) with values obtained for different nanocomposites were correlated with the degree of reinforcement. It can be assumed that more polymer chains are attached on to the surface of the filler and there exists an immobilized layer around the filler surface and the layers do not take part in the relaxation process. The FTIR spectrum of the different samples highlighted the possible filler matrix interaction. The filler dispersion and aggregation in the polymer matrix were analyzed using X-ray diffraction studies (XRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM).
Preparation and mechanical properties of nitrile butadiene rubber/silicate nanocomposites
2004
Elastomer nanocomposites consisting of nitrile butadiene rubber (NBR) latex and layered silicates are prepared by a modified latex shear blending process aided with ball milling. The mode of dispersion of layered silicates in NBR is partially exfoliated and intercalated when the concentration of layered silicates is below 7.5 wt%, as evidenced by transmission electron microscopy and X-ray diffraction results. The tensile and tear mechanical properties are much higher than that of neat NBR. Specifically, the tensile and tear mechanical properties of the NBR/layered silicates increase by 200 and 60%, respectively. The decomposition temperature of the nanocomposites increases slightly. q
Recent advancements in rubber nanocomposites
2014
Nanocomposites were prepared via melt blending, based on organically modified clays (OC), carbon nanotubes (CNT), and graphitic nanofillers made by a few layers of graphene (nanoG). In particular, nanocomposites based on a hybrid filler system, with a nanostructured filler such as carbon black (CB), are examined. It is shown that low crystalline order in the interlayer space of a layered nanofiller (such as OC and nanoG) leads to easier delamination. Nanofillers give rise to filler networking at low concentration, particularly in the presence of CB. Hybrid filler systems lead to nanocomposites' having initial moduli that are much higher than those calculated through the sum of the initial modulus of composites containing either only CB or only the nanofiller. Nanofillers enhance the matrix modulus by a multiplication factor that depends only on the nanofiller type and content, regardless of whether the matrix is a neat or a CB-filled polymer. Furthermore, the fillerpolymer interfacial area is shown to be a parameter able to correlate the mechanical behavior of both nano-CNT and nanostructured (CB) fillers. By plotting values of the composite initial modulus versus the filler-polymer interfacial area, points due to CB, CNT, and the hybrid CB-CNT system lie on the same curve.
In Situ Zirconia: A Superior Reinforcing Filler for High-Performance Nitrile Rubber Composites
Zirconia particles are generated into a nitrile rubber (NBR) matrix via a solution sol−gel method in a controlled manner. Formation of zirconia particles from their precursor (zirconium(IV) propoxide) occurs under optimized reaction conditions. As a result, the nanoparticles are embedded and well dispersed in the NBR matrix that results in a remarkable improvement in mechanical and thermal properties of the composite. Such reinforcement is not realized when the composites are prepared following the conventional technique of filler loading by physical mixing, although the filler content remains the same. Use of a surface active coupling agent TESPT (bis-(3-triethoxysilylpropyl) tetrasulfide) in the reactive sol−gel system is found to further boost the mechanical performance of the composites. In order to ensure the practical application of the developed composites, a series of studies have been performed that consist of dynamic performance, swelling, thermal degradation, and resistance to oil, ozone, and abrasion. Analysis of the results reveals that in situ zirconia could be an excellent filler for the NBR composites to withstand in a harsh and adverse environment.
Applied Clay Science, 2014
To reduce material consumption, it is important to have reinforced material with longer life time. Incorporation of nanoparticles to reinforce and compatibilize polymer blends is one of the widely undergoing research areas in polymer science technology. A series of natural rubber and nitrile rubber (NR/NBR) nanocomposite vulcanazite, reinforced with two different organically modified clay (OMt) were prepared. To predict the performance of a material over long periods of time, stress relaxation studies with both the reinforced systems were done. The effects of loading, blend composition, filler polarity and temperature on stress relaxation of OMt reinforced NR/NBR nanocomposites were carefully measured. Based on the stress relaxation measurements, it was observed that due to its polarity difference, O1Mt (Mt modified with dimethyl, benzyl, HT modification provided by Southern Clay Products) was preferentially located at the NBR phase while O2Mt (Mt modified with mercapto silane provided by English India Clay) had more affinity with natural rubber in the NR/NBR nanocomposites. The preferential localization of OMt has been analyzed by HRTEM. The nature of interaction of the nanoclay was found to influence the stress relaxation rate. NR/NBR nanocomposites with higher filler loading showed higher rates of relaxation rate due to the presence of more filler-filler interactions. At 70°C, the viscosity ratio was found to influence the reinforcement, and consequently relaxation rate of the 50/50 NR/NBR nanocomposites. It was found that the rearrangements of the polymer chains are dependent on the blend composition, temperature, filler/polymer interactions etc. To explain and predict observed phenomena, the stretched-exponential Kohlrausch equation and Maxwell-Weichert model were used. For both models, the experimental curve fitted well with the theoretical models.
Journal of Applied Polymer Science, 2005
The morphology and mechanical and viscoelastic properties of rubbery epoxy/organoclay montmorillonite (MMT) nanocomposites were investigated with wideangle X-ray scattering (WAXS), transmission electron microscopy (TEM), tensile testing, and dynamic mechanical thermal analysis. An ultrasonicator was used to apply external shearing forces to disperse the silicate clay layers in the epoxy matrix. The first step of the nanocomposite preparation consisted of swelling MMT in a curing agent, that is, an aliphatic diamine based on a polyoxypropylene backbone with a low viscosity for better diffusion into the intragalleries. Then, the epoxy prepolymer was added to the mixture. Better dispersion and intercalation of the nanoclay in the matrix were expected. The organic modification of MMT with octadecy-
Mechanical Properties of Rubber Nanocomposites: How, Why... and Then
HAL (Le Centre pour la Communication Scientifique Directe), 2010
Through the review of literature, this chapter will first recall the typical mechanical behaviour of rubber filled with nanofillers, from the viscoelastic linear behaviour to the large deformation one, including the ultimate properties. Then we will highlight the main filler parameters and how they seem to control these properties. In particular, we will focus on the role of filler-filler and filler matrix interactions, which are necessarily important when dealing with fillers with such high specific surface (up to several hundreds of meter square per gram). We will also see the influence of these fillers on the matrix properties, since, for instance, the filler presence can modify the matrix crosslinking kinetic or induce crystallization. Then, this description will be completed by the introduction of different modelling approaches developed to account for and eventually predict the role of nanofillers in the mechanical behaviour of these rubber nanocomposites.
Macromolecular Symposia, 2017
Properties of the unfilled rubber blends (Natural rubber, NR and Nitrile Butadiene Rubber, NBR) were poor due to the absence of reinforcing agent. However, the strength of compound had been improved with the addition of nanofiller. There were two (2) types of nanofillers that had been introduced which are nanoclay (NC) and nanosilica (NS). NR/NBR composites were prepared by open milling process where different amount of nanofiller was added ranging from 1 until 7 phr. There are a few possibilities might occur when using small particles size of fillers especially in term of interaction between rubber-filler and filler-filler interaction. Apart from that, different polarity and composition of both rubbers were influenced the interaction between filler and rubber phases. The interaction between non-polar and polar rubber was enhanced using epoxidized natural rubber (ENR). The rubber compound was cured via a conventional sulphur vulcanization system. The cure characteristic result shows that the incorporation of nanofiller does not affect much on the t 90. The physical and mechanical properties of epoxidized natural rubber (ENR) compatibilized NSi-NR/NBR blends were determined by conducting the density measurements, hardness and tensile tests. The NC filler gave the highest tensile strength compared to NS. On top of that, reduction trend on the tensile strength observed at 3 phr of NS loading due to the formation of NS aggregates. The values of moduli, hardness and densities of vulcanizates increased as the nanofiller loading increased. It occurs due to better filler dispersion in the rubber matrix and strong interaction between filler-rubber phases. The result shows that NC has more pronounce effect on the physical and mechanical proportion of the rubber vulcanizates.
Plastics Rubber and Composites, 2017
Industry is constantly demanding for materials with differential properties that explores nanoscale fillers functionality. Unfortunately, most of the papers present processing methods that are hard to scale up. Effects in addition different amounts of multiwall carbon nanotubes (MWCNT) and few-layer graphene (FLG) on cure behaviour, viscoelastic, mechanical and electrical properties of a hydrogenated nitrile butadiene rubber (HNBR) are investigated and compared with those composites having carbon black (CB) as filler. Looking for scale up the produced nanocomposites, rubber composites were produced in a closed mixing chamber by melt mixing with unmodified fillers. Addition of nanotubes reduces curing time. Microstructural analyses indicate that FLG cannot be easily dispersed by this methodology. Significant improvement in mechanical properties is observed with MWCNT addition, with 940% modulus increment regarding to the pure polymer and also, in lower intensity, in HNBR/FLG composites. Moreover, HNBR/MWCNT composites presented a sharp reduction in electrical resistivity at low loading level.