Elastomer nanocomposites fillers

IV. The Mix A Nanocomposite of Elastomer and Filler V. Mechanical Properties of Filled Rubbers... 

Introductory paragraphs similar to the above can be found in hundreds of nanocomposite papers. With the exception of reinforced elastomers, nanocomposites have not lived up to expectations. Although claims of modulus enhancement by factors of 10 exist, these claims are offset by measurements that show little or no improvement... The lackluster performance of nanocomposites has been attributed to a number of factors including poor dispersion, poor interfacial load transfer, process-related deficiencies, poor alignment, poor load transfer to the interior of filler bundles, and the fractal nature of filler clusters [5]. 

Yamashita K, Funato T, Suzuki Y, Teramachi S, Doi Y (2003) Characteristic interactions between poly(hydroxybutyrate) depolymerase and poly [(R)-3-hydroxybutyrate] film studied by a quartz crystal microbalance. Macromol Biosci 3 694—702 Yang L, Setyowati K, Li A, Gong S, Chen J (2008) Reversible infrared actuation of carbon nanotube-liquid crystalline elastomer nanocomposites. Adv Mater 20 2271-2275 Yu C, Shi L, Yao Z, Li D, Majumdar A (2005) Thermal conductance and thermopower of an individual single-wall carbon nanotube. Nano Lett 5 1842-1846 Yu H, Qin Z, Zhou Z (2011) Cellulose nanocrystals as green fillers to improve crystallization and hydrophilic property of poly(3-hydroxybut3uate-co-3-hydroxyvalerate). Prog Nat Sci Mater Int 21 478 84... 

Fillers of various dimensions are added to polymers to alter its processability, properties and uses. Such micro and nano composites obtained may have tremendous possibilities in industries and information on their viscoelasticity is very necessary as far as their processing and applicability are concerned. The dynamic properties of filled elastomers have been a subject of active research since they affect the performance of tyres such as skid, traction, and rolling resistance. Elastomer nanocomposites are most important materials characterized by excellent elasticity and flexibility, and are widely used in various applications such as cables, tyres, tubing, dielectric materials and sensors [1-5]. The non linear features observed in filled elastomers upon a simple shear are as follows. The dynamic storage and loss moduli of the composites are only dependent on the dynamic strains and not on the static strain. In the same way the stress strain curves also do not depend on static strain. Moreover the initial modulus under constant strain rate is highly rate dependent whereas the terminal modulus is independent of strain rate. This initial to terminal modulus ratio in the stress-strain curves is the same as the ratio of the dynamic storage moduli obtained at low and high strains. 

Keywords layered fillers, layered silicates, montmorillonite, elastomers, nanocomposites, intercalation, exfoliation, ionic liquids. 

Even if the term nanocomposite is usually not used in reinforcement by particulate fillers, it would be particularly adapted mixing of reinforcing solids and elastomers is not limited to the arithmetic sum of the properties of both taken independently but gives a synergetic alliance that achieves new properties. 

In in-situ polymerization, nanoscale particles are dispersed in the monomer or monomer solution, and the resulting mixture is polymerized by standard polymerization methods. This method provides the opportunity to graft the polymer onto the particle surface. Many different types of nanocomposites have been processed by in-situ polymerization. Some examples for in-situ polymerization are polypyrrole nanoparticle/amphiphilic elastomer composites magnetite coated multi-walled carbon nanotube/polypyrrole nanocomposites and polypyrrole/ silver nanocomposites. The key to in-situ polymerization is appropriate dispersion of the filler in the monomer. This often requires modification of the particle surface because, although dispersion is easier in a liquid than in a viscous melt, the settling process is also more rapid. 

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