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The localization of organically modified nanoclays in chlorobutyl rubber (CIIR) and natural rubber (NR) blend system was carefully studied by following the vulcanization behaviour, morphology, thermal and solvent permeation characteristics. From the vulcanization studies, it was observed that incorporation of nanoclay platelets significantly affected the viscosity and vulcanization parameters such as cure time, scorch time, rate of cure and the degree of cure. Thermal analysis pointed out that the addition of nanoclay increased the thermal stability of the elastomer blends. The morphology of the blends indicated that the nanoclay platelets were localized at the interface and in both phases (mixed mode morphology) of elastomer blends and this affected the overall properties. The transport characteristics of NR/CIIR blend nanocomposites using toluene as the solvent were also studied. The transport parameters such as the equilibrium uptake, diffusion coefficient and the rate constant have been computed. The transport characteristics have been correlated with the microstructure of the blend nanocomposites. Finally, applied the Peppas–Sahlin model to fit the experimental diffusion data and the fitting was found to be reasonably good. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers

Nanocomposites comprising carbon nanofibers (CNF) were prepared and evaluated in terms of morphology, mechanical performance, thermal stability and crystallization properties. It was found that addition of CNF reinforced polypropylene (PP) matrix by marginally increasing the strength and modulus, but at the expense of toughness and ductility. To improve the toughness of the composites, polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) was used. Presence of SEBS remarkably improved the toughness and ductility of the composites. The optimum level of reinforcement was observed at 0.1 wt% of CNF in the composites. Phase morphology studies revealed that at this concentration, CNF were well dispersed in polymer phases and beyond it, agglomeration occurred. PP/SEBS/CNF (0.1 wt%) nanocomposites exhibited good strength, excellent toughness and decent modulus, which make them suitable for cost effective, light-weight, tough and stiff material for engineering applications. It was observed that thermal stability of composites is only marginally improved whereas crystallinity of PP drastically reduced by the addition of CNF. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

The present study focuses on the preparation of a novel hybrid epoxy nanocomposite with glycidyl polyhedral oligomeric silsesquioxane (POSS) as nanofiller, carboxyl terminated poly(acrylonitrile-co-butadiene) (CTBN) as modifying agent and diglycidyl ether of bisphenol A (DGEBA) as matrix polymer. The reaction between DGEBA, CTBN, and glycidyl POSS was carefully monitored and interpreted by using Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC). An exclusive mechanism of the reaction between the modifier, nanofiller, and the matrix is proposed herein, which attempts to explains the chemistry behind the formation of an intricate network between POSS, CTBN, and DGEBA. The mechanical properties, such as tensile strength, and fracture toughness, were also carefully examined. The fracture toughness increases for epoxy/CTBN, epoxy/POSS, and epoxy/CTBN/POSS hybrid systems with respect to neat epoxy, but for hybrid composites toughening capability of soft rubber particles is lost by the presence of POSS. Field emission scanning electron micrographs (FESEM) of fractured surfaces were examined to understand the toughening mechanism. The viscoelastic properties of epoxy/CTBN, epoxy/POSS, and epoxy/CTBN/POSS hybrid systems were analyzed using dynamic mechanical thermal analysis (DMTA). The storage modulus shows a complex behavior for the epoxy/POSS composites due to the existence of lower and higher crosslink density sites. However, the storage modulus of the epoxy phase decreases with the addition of soft CTBN phase. The Tg corresponding to epoxy-rich phase was evident from the dynamic mechanical spectrum. For hybrid systems, the Tg is intermediate between the epoxy/rubber and epoxy/POSS systems. Finally, TGA (thermo gravimetric analysis) studies were employed to evaluate the thermal stability of prepared blends and composites. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers