Viscoelastic Behavior and Reinforcement Mechanism in Rubber Nanocomposites in the Vicinity of Spherical Nanoparticles

Abstract

The viscoelastic behavior and reinforcement mechanism of nano ZnO reinforced natural rubber (NR) nanocomposites were investigated in this study. Dynamic mechanical analysis was performed to investigate the nature of the constrained polymer region in NR−nano ZnO nanocomposites, and the constrained polymer region is responsible for the reinforcement mechanism. The viscoelastic and tensile properties of NR nanocomposites were investigated with respect to the effect of nanofiller loading. All the nanocomposites showed a significant increase in storage modulus in the glassy and rubbery regions, the shift of the tan δ peak to the higher temperature region, and the lowering of the tan δ peak intensity compared to neat NR. The enhancement in the modulus is related to the weight % of the added nano ZnO as well as the volume of the constrained rubber chains in the proximity of ZnO nanoparticles. The study of the constrained volume of the polymer indicates that the structure of the nanocomposite possesses a moderately strong interfacial interaction between rubber chains and ZnO nanoparticles. The type of rubber−nanofiller interaction strongly influences the amount and modulus of the constrained region and contributes to the enhancement in the storage modulus of the resulting nanocomposites. The volume fraction of the constrained region of the NR nanocomposites was found to have good linear correlation with the weight % of nano ZnO. It was also understood that there should exist an optimum cross-linking density for a certain nanofiller reinforced rubber system, as well as partial physical adsorption of macromolecular rubber chains on the nanofiller surface. An optimum nanofiller loading is necessary for moderately strong rubber−nanofiller interaction and hence for the enhancement in the mechanical properties of the NR nanocomposites. A core−shell morphology model and constrained polymer model have been proposed to explain the constrained polymer chains in the NR−nano ZnO nanocomposite system on the basis of these results.

Structure, Mechanical, Thermal and Fire Behavior Assessments of Environmentally Friendly Crude Glycerol-Based Rigid Polyisocyanurate Foams

“…Decreasing values of loss tangent are in line with the increasing cross-link density of analyzed PIR foams. The lower value of tan δ, the more elastic is the material, high values are typical for materials with a high, nonelastic strain component, which show enhanced possibility for energy dissipation by molecular motions [47]. In the Fig.…”

Processing and structure–property relationships of natural rubber/wheat bran biocomposites

“…This indicates better adhesion at the matrix-filler interface and is in agreement with previous studies (Cao et al 2005;Sormana and Meredith 2004;Tarakcilar 2011). Bindu and Thomas, based upon the information and formulas presented by Abdalla and Kojima (Abdalla et al 2007;Bindu and Thomas 2013;Kojima et al 1993), proposed a method for calculation of the amount of polymer chains immobilized through matrix-filler interactions in accordance with formula (12):…”

Free-volume correlation with mechanical and dielectric properties of natural rubber/multi walled carbon nanotubes composites

“…For instance, PALS is correlated with the mechanical and dynamic mechanical properties of nanocellulose filled polyurethane [15] whereas it is used to derive the gas permeability of the same polymer using fullerene as the reinforcement [16]. Our group has also addressed the various properties of polymer nanocomposites using the PALS technique [17,18], wherein the method was simply applied to characterize the clay and spherical particles filled composites.…”