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Abstract: Transport properties of aromatic solvents such as benzene, toluene and p-xylene through micron sized fillers reinforced natural rubber, carboxylated styrene butadiene rubber and their 70/30 blend latex membranes were investigated. The effect of penetrant size, filler loading and temperature on the diffusion properties were studied. The dispersion of filler in the matrix were analysed from scanning electron micrographs. Due to the lack of polymer/filler interaction aggregation of filler was higher in NR. The filled samples showed reduced swelling rate owing to the tortuosity of the path. A dramatic decrease in diffusion coefficient of filled samples was observed. However, blend system exhibited unexpected diffusion behaviour because of the immiscibility of the two components. The activation energies for diffusion of the penetrant were computed from the Arrhenius plots. The activation energy needed for diffusion of penetrant was found to be higher for filled virgin polymers. The transport mechanism was investigated and found that all systems exhibited non-Fickian anomalous behaviour. [Copyright &y& Elsevier]

Abstract: Solvent resistance properties of nano-structured layered silicates filled natural rubber (NR), carboxylated styrene butadiene rubber (XSBR) and their 70/30 latex blend were investigated by equilibrium swelling method using benzene, toluene and p-xylene. The layered nano-structured sodium bentonite and sodium fluorohectorite were used in the present study. The impact of concentration of filler, temperature and penetrant size on the transport properties of aromatic solvents through layered silicates reinforced latex membranes were analysed. The transport properties of filled latex membranes was analysed as a function of extent of exfoliation of the layered silicate in the rubber matrix. The morphology of filler dispersion in the rubber matrix was analysed from transmission electron micrographs. More exfoliated structure was found in sodium-fluorohectorite filled latex membrane. The extent of intercalation of polymer chain into the layers of silicates was estimated using X-ray diffraction technique. The enhanced d-spacing in latex nanocomposite indicated the intercalated structure. Nanocomposite of natural rubber (NR), carboxylated styrene butadiene rubber (XSBR) and their blends showed reduced swelling rate due to the tortuosity of the path and the reduced transport area in polymeric membrane. [Copyright &y& Elsevier]

Conductive carbon black (CCB), carbon nanotubes (CNT) and its hybrids are introduced into the natural rubber (NR) matrix aiming to explore the effect of filler ratio on the transport properties. Solvent transport of NR is found to decrease for hybrid filler systems as compared to single filler incorporated systems. Kinetic parameters of solvent transport behavior of filled NR systems are analyzed using various kinetic models. Upon the computation of kinetic parameters of transport data, it is found that the Peppas-Sahlin model is in good agreement with experimental observations, which suggests that the transport mechanism is diffusion controlled. Rubber-filler interaction parameters are computed and analyzed from the swelling experiments using Kraus, Cunneen-Russel, and Lorenz-Park equations. [ABSTRACT FROM AUTHOR]

The versatility and potential have framed natural rubber (NR) nanocomposites as the focal point in the polymer research field and industry. Currently, NR nanocomposites filled with hybrid nanostructures is an interesting area than single filler or conventional filler systems. Halloysite nanotube (HNT) and bentonite clay are well-studied potential fillers of polymers. This work is an attempt to study the effect of hybrid filler system of HNT and organically modified bentonite nanoclay (NC) in the properties of NR. NR/HNT-NC systems with varied filler concentrations were prepared in a two-roll mixing mill. Properties such as cure characteristics, morphology, mechanical, thermal, and transport behavior were analyzed in detail. The prepared composites had better wear properties than gum vulcanizates. Improvement in physical properties was observed due to the increased contact surface area between the filler and the matrix. The nanocomposite with 2 wt% hybrid filler shows a 31% decrease in abrasion loss compared to neat NR composite. Apparently, 4 wt% of hybrid filler could improve modulus at 300% strain and tear by approximately 57% and 14%, respectively. The ability to withstand high strain was evident from the improved crack growth resistance as observed in micrographs. Lorenz–Park plots were employed to analyze the rubber–filler interaction. The activation energy of thermal degradation was calculated using Coats–Redfern equation. [ABSTRACT FROM AUTHOR]