Transport of organic solvents through natural rubber/nitrile rubber/organically modified montmorillonite nanocomposites

The article describes the transport phenomenon of some commonly used laboratory organic solvents which differ in their solubility parameter value through polymer blend nanocomposites membrane prepared by melt mixing. The three solvents that were used are hexane, toluene and xylene which differed widely in their solubility parameter values. The motivation for the study was to know the effect of solubility parameter on the diffusion transport properties of NR/NBR (natural rubber/nitrile rubber) blends. The solvent uptake, diffusion, sorption and permeation constants were investigated and were found to decrease with organically modified montmorillonite (OMt) content at lower loading. The mode of transport through NR/NBR nanocomposites was found to be anomalous. The difference in solubility parameter value greatly influenced the transport properties. The dependence of various properties on OMt content was supported by morphological analysis data. The effect of blend ratio, solvent size and OMt loading on the diffusion of aromatic and aliphatic solvents through NR/NBR blend systems were investigated. The swelling coefficient values also decreased upon the addition of fillers indicating the presence of hindered path for solvents to diffuse into the polymer matrix. The better reinforcement at lower filler loading was confirmed from the cross-link density values and mechanical properties. The transport data obtained were applied to mathematical models for predicting the diffusion behaviour through nanocomposite membranes and to elucidate the physical mechanism of transport.

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