The effect of carbon black fillers viz. semireinforcing furnace (SRF), high abrasion furnace (HAF) and intermediate super abrasion furnace (ISAF) carbon blacks on the cure, swelling and mechanical properties of 70/30 EPDM/NBR blend have been investigated. The maximum torque values have been found to be increased with increase in filler loading. Filledsystems have been found to exhibit a reduced solvent uptake tendency compared to the unfilled sample. Blends loaded with ISAF exhibited the lowest toluene uptake among the carbon black filled systems due to the better filler reinforcement. A more uniform morphology has been observed for ISAF-filled samples compared to the other filler loaded systems. The improvement in the mechanical properties has been observed to be the highest for ISAF-filled samples followed by HAF and SRF filled systems. This has been attributed to the smaller particle size of ISAF black. The experimental results of mechanical testing have been compared with various theoretical models.
Natural rubber (NR)/Acrylonitrile butadiene rubber (NBR) blend membranes, prepared by using dicumyl peroxide as the crosslinking agent, were tested for their vapor permeation characteristics. The permeation studies were conducted using three chlorinated hydrocarbons, viz. dichloro methane, chloroform, and carbon tetrachloride. The effects of the blend ratio, compatibilizer, penetrant size, and temperature on the vapor permeability of the membranes were investigated. The permeability of the blends was found to decrease with an increase in the NBR content, which has been attributed to the inherent solvent resistant nature of NBR. The permeation behavior of compatibilized blends was compared with those of the uncompatibilized blends. The separation efficiencies of the membranes were also tested using chloroform/acetone mixtures to complement the observations from the vapor permeation experiments.
Phenol is an industrially important chemical, generally produced via sulphuric acid catalysed decomposition of cumene hydroperoxide (CHP). The effluent containing the acid used as catalyst has to be neutralised and extracted to avoid corrosion and environmental problems. In the current work, a simple process was developed based on the use of nanocrystalline ZSM-5 (Si/Al = 100) catalyst. The catalyst was characterised by XRD, SEM, TEM, DLS and FT-IR analyses. The activity of this catalyst was tested for the liquid-phase decomposition of cumene hydroperoxide. The effects of various parameters such as, catalyst weight, catalyst particle size, concentration of CHP, reaction temperature and reusability of catalyst were studied. It was observed that the nanocrystalline ZSM-5 with smaller particle size showed superior activity. In addition, these catalysts have excellent reusability and can be used instead of sulphuric acid for selective decomposition of CHP into phenol and acetone with 100% conversion.
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