Rubber nanocomposites viscoelastic properties

Sarvestani AS, Jabbari E (2010) Nonlinear viscoelastic behavior of rubbery bionanocomposites. In Stephen R, Thomas S (eds) Rubber nanocomposites preparation, properties, and applications. Wiley Online Library, Singapore, p 331... 

Abstract This chapter describes the influence of three-dimensional nanofillers used in elastomers on the nonlinear viscoelastic properties. In particular, this part focuses and investigates the most important three-dimensional nanoparticles, which are used to produce rubber nanocomposites. The rheological and the dynamic mechanical properties of elastomeric polymers, reinforced with spherical nanoparticles, like POSS, titanium dioxide and nanosdica, were described. These (3D) nanofillers in are used polymeric matrices, to create new, improved rubber nanocomposites, and these affect many of the system s parameters (mechanical, chemical, physical) in comparison with conventional composites. The distribution of the nanosized fillers and interaction between nanofUler-nanofiUer and nanofiller-matrix, in nanocomposite systems, is crucial for understanding their behavior under dynamic-mechanical conditions. 

The studies of nonlinear viscoelastic behavior have been performed not only for rubber matrices, but also reported for polyolefin matrices, for example polypropylene-reinforced Ti02 nanoparticles. Work by Bahloul et al.—concerning preparation of PPA i02 nanocomposites based on the sol-gel method—reported strain dependence of the viscoelastic properties. The authors observed a change in the storage modulus (G ) versus the strain amplitude and a characteristic decrease. 

In this chapter, the rheology and the dynamic-mechanical behavior of iso-dimensional rubber nanocomposites in the non-linear zone have been reviewed. Briefly described were the effect of nanofiller on the nonlinear viscoelastic properties of rubbers and the mechanism of nonlinearity in these polymeric systems. 

Abstract This chapter deals with the non-linear viscoelastic behaviour of rubber-rubber blend composites and nanocomposites with fillers of different particle size. The dynamic viscoelastic behaviour of the composites has been discussed with reference to the filler geometry, distribution, size and loading. The filler characteristics such as particle size, geometry, specific surface area and the surface structural features are found to be the key parameters influencing the Payne effect. Non-Unear decrease of storage modulus with increasing strain has been observed for the unfilled vulcanizates. The addition of spherical or near-spherical filler particles always increase the level of both the linear and the non-linear viscoelastic properties. However, the addition of high-aspect-ratio, fiber-like fillers increase the elasticity as well as the viscosity. 

The viscoelastic properties of natural rubber (NR) nanocomposites filled with silica/multiwall carbon nanotube hybrid fillers have been studied by H. Ismail et al. [46]. The addition of hybrid fillers (MWCNTs-i-silica) to the NR matrix... 

For better performance the fillers must have good interfacial interaction with the rubber medium. This is a matter of great importance and Sadasivuni and Grohens have addressed the nonlinear viscoelasticity of mbber reinforced nanoplatelets based on such molecular interactions existing in the system. The filler-filler and filler-rubber interactions are studied with the help of rheology and certain theories. For this the nonlinear stress response of rubbers and its composites to an applied strain is noted and it is found that the 2D filler particles increase the level of viscometric properties. Here in this chapter the readers will get a basic knowledge about an important behavior of rubber nanocomposites which is known as Payne effect. 

Dynamically vulcanized thermoplastic elastomer (TPV)/organoclay nanocomposites based on EPDM/PP containing 2, 4, 6% of organically treated montmorillonite were prepared by using EPDM-g-MA and PP-g-MA as compatibilizer. Dicumylperoxide (DCP) and triallyl cyanurate (TAC) were employed as crosslinking system. X-ray diffraction (XRD) analysis has been performed to evaluate the extent of the intercalation.. In this study, attempts have been made to exclusively reinforce rubber dispersed phase. Rheological behavior and melt viscoelastic properties of the samples such as elastic modulus, and elastic response expressed in terms of relaxation time distribution, H (A), were studied. The results were also supported by differential scanning calorimetry (DSC) and mechanical tests. 

Adsorption of rubber over the nanosilica particles alters the viscoelastic responses. Analysis of dynamic mechanical properties therefore provides a direct clue of the mbber-silica interaction. Figure 3.22 shows the variation in storage modulus (log scale) and tan 8 against temperature for ACM-silica, ENR-silica, and in situ acrylic copolymer and terpolymer-silica hybrid nanocomposites. 

This technique has found the following applications in addition to those discussed in Sections 10.1 (resin cure studies on phenol urethane compositions) [65], 12.2 (photopolymer studies [66-68]), and 13.3 (phase transitions in PE) [66], Chapter 15 (viscoelastic and rheological properties), and Section 16.4 (heat deflection temperatures) epoxy resin-amine system [67], cured acrylate-terminated unsaturated copolymers [68], PE and PP foam [69], ethylene-propylene-diene terpolymers [70], natural rubbers [71, 72], polyester-based clear coat resins [73], polyvinyl esters and unsaturated polyester resins [74], polyimide-clay nanocomposites [75], polyether sulfone-styrene-acrylonitrile, PS-polymethyl methacrylate (PMMA) blends and PS-polytetrafluoroethylene PMMA copolymers [76], cyanate ester resin-carbon fibre composites [77], polycyanate epoxy resins [78], and styrenic copolymers [79]. 

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