Preparation and mechanical properties of nitrile butadiene rubber/silicate nanocomposites (original) (raw)
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Polymer Composites, 2009
Acrylonitrile-butadiene rubber (NBR) nanocomposites with layered silicate (LS), calcium phosphate (CP), and titanium dioxide (TO) of different particle size were prepared in an open two-roll mixing mill at different filler loading in presence of sulphur as vulcanizing agent. The layered silicate (LS) filled system showed outstanding enhancement in mechanical properties in comparison with nanocalcium phosphate (CP) and titanium dioxide (TO). The variations in properties can be attributed to the extent of intercalation/exfoliation, which was highly influenced by the filler size. The layered silicate filled system at 20 phr showed nearly 349% increase in tensile strength compared to pure NBR whereas an increase of 110% and 84% were shown by CP and TO filled systems respectively. The modulus enhancements were in the order of 200%, 63% and 22%, respectively compared to the unfilled system. The increase in tear resistance was in the order of 230%, 115%, and 41% respectively for the filled systems in comparison with unfilled NBR. The significant enhancements in mechanical properties were supported by the morphological analysis. POLYM. COMPOS., 31:1515–1524, 2010. © 2009 Society of Plastics Engineers
Materials & Design, 2009
The most important factor, which indicates the improvement of properties in rubber by nanoclay, is the distribution in the rubber matrix. The simple mixing of rubber and nanoclay will not exfoliate the filler in the rubbery matrix. Hence, some sort of compatibilizer like epoxidized natural rubber (ENR) can be utilized safely in exfoliating the nanoclay in the matrix polymer. Epoxidized natural rubber and organically modified nanoclay composites (EC) were prepared by solution mixing. The nanoclay employed in this study was Cloisite 20A. The obtained nanocomposites were incorporated in nitrile butadiene rubber (NBR) with sulphur as a curing agent. The morphological study showed the intercalation of nanoclay in ENR and further incorporation of EC in NBR matrix leads to exfoliation of nanoclay. Curing study demonstrated faster scorch time, cure time and increase in maximum torque for the EC incorporated NBR compounds compared to pure NBR. Dynamic mechanical thermal analysis showed increase in storage modulus and lesser damping characteristics for the compounds containing EC loading in NBR matrix. In addition, these particular compounds showed enhancement in overall mechanical properties, higher swelling resistance in oil and solvent and decrease in compression set due to higher reinforcing efficiency of nanoclay in the NBR matrix.
Preparation and Studies of Nitrile Rubber Nanocomposites with Silane Modified Silica Nanoparticles
Research Journal of Recent Sciences …
Rubber silica nanocomposites are prepared by mixing nitrile rubber (NBR) with surface modified silica nano particles. Silica nano particles are synthesized by sol-gel method that involves hydrolysis followed by condensation of tetraethyl orthosilicate (TEOS). Surface modification of silica particles is done with the treatment of silane coupling agent viz. 3-mercaptopropyltrimethoxysilane. Presence of silane coupling agent in silica is revealed by IR studies. Thermogravimetric analysis is done to find out silica content in the composites and to study the thermal properties. Stress strain studies are found to be useful to assess the improvement of the mechanical properties of the composites.
Polymer Engineering & Science, 2005
We have prepared nanocomposites of intercalated and exfoliated organosilicates in butadiene rubber (BR) by using a two-stage melt blending process. We used X-ray diffraction and transmission electron microscopy to examine, respectively, the intergallery spacing of the organosilicates and their dispersion in the BR. Marked enhancements in the mechanical and thermal properties of BR occurred when it incorporated <10 parts of organosilicates and the loading ratio of the organosilicate to dicarboxylic acid-terminated butadiene oligomer was approximately three. In particular, the addition of 10 parts of organosilicate and 3 parts of compatibilizer in the BR led to a more than four-fold increase in the tensile strength, a 150% increase in modulus at 100% elongation (M100), and 232 and 410% enhancements in the tear strength and elongation at break, respectively, relative to those of neat BR. The degradation temperature for the BR nanocomposite containing only a 10-part loading of organosilicate was 51°C higher than that of neat BR; these increases reduced, however, to 9-13°C upon the addition of the CTB compatibilizer. In addition, the relative water vapor permeabilities of the BR nanocomposites containing 10 parts of organosilicate-both in the presence and absence of the compatibilizer-reduced to 20% of that of the neat BR.
Journal of Applied Polymer Science, 1995
Variation of dynamic mechanical properties like storage modulus (E') and loss tangent (tan 6) with temperature show the presence of two transitions in the carboxylated nitrile rubber (XNBR) molded in the presence of zinc oxide (ZnO). The low-temperature transition is due to the glass-rubber transition (T,) of XNBR, and the high-temperature transition is due to formation of ionic clusters. Incorporation of reinforcing silica filler makes the hightemperature transition more prominent and high filler loading causes a shift of the transition temperature to the higher side. It is believed that the rubber-filler interaction in the cluster region causes striking changes in the variation of E and tan 6 with a double-strain amplitude (DSA).
Physical-mechanical behavior of nitrile rubber-synthetic mica nanocomposites
Polímeros
Nitrile rubber (NBR) nanocomposites with different contents of synthetic Somasif ME-100 mica (sodium-fluorohectorite) were obtained by melt compounding using a Semi Efficient curing system. The effect of curing on the nanocomposties was evaluated through rheometric properties, crosslink density (CLD) and mechanical properties. The ME-100 mica dispersion in NBR was assessed by transmission electron microscopy (TEM), the Payne effect and thermodynamic properties (ΔS and ΔG). Both the curing parameters and CLD pointd out that the addition of ME-100 directly affects crosslinks formation. It could also be observed that the nanofiller dispersion state is complex, exhibiting exfoliated and agglomerated structures (TEM); besides, agglomerations rose linearly as the nanofiller was added (the Payne effect). Notwithstanding these findings, and on the basis of unfilled formulations, NBR20 nanocomposite showed improvement in mechanical properties (tensile and tear strengths) which suggests that ME-100 might be considered a semi-reinforcing filler.
Effect of Nano Silica on the Mechanical Properties of Styrene-Butadiene Rubber (SBR) Composite
The aim of this research is to study the effect of nano silica which use as a filler with loading level (0.1, 0.3, 0.5, 1, 3, 5, 10, 20, 30, 40 pphr) on mechanical properties of SBR such as Tensile strength, elastic modulus, hardness, abrasion, fatigue and tear resistance. The results show that on addition of small quantities of nano silica an increase of mechanical properties occurs. While at high percent of nano silica aggregation in rubber matrix occurs and decrease themechanical properties.
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-
Silica particles were generated and grown in situ by sol-gel method into rubber blends comprised of natural rubber (NR) and acrylonitrile butadiene rubber (NBR) at various blend ratios. Silica formed into rubber matrix was amorphous in nature. Amount of in situ silica increased with increase in natural rubber proportion in the blends during the sol-gel process. Morphology studies showed that the generated in situ silica were nanoparticles of different shapes and sizes mostly grown into the NR phase of the blends. In situ silica filled NR/NBR blend composites showed improvement in the mechanical and dynamic mechanical behaviors in comparison to those of the unfilled and externally filled NR/ NBR blend composites. For the NR/NBR blend at 40/60 composition, in particular, the improvement was appreciable where size and dispersion of the silica particles into the rubber matrix were found to be more uniform. Dynamic mechanical analysis revealed a strong rubber-in situ silica interaction as indicated by a positive shift of the glass transition temperature of both the rubber phases in the blends.