Gas Permeability of PTMSP/Silica Nanocomposite Films
A.L. Andrady, L.G. Toy and T.C. Merkel
RTI International, US
permeability, fumed silica, gas
Incorporation of nanoscale impermeable particles of fumed silica into a superglassy polymer matrix of poly(trimethylsilylpropyne), PTMSP, resulted in an unexpected increase in its gas permeability. This implies a corresponding increase in the fractional glassy free volume of the polymer due to the presence of silica nanoparticle. 129Xe NMR studies on the composites were used as an independent probe technique to establish this creation of additional free volume. This unusual gas transport phenomenon is qualitatively interpreted in terms of the interconnected void volumes at the interface of the filler particle agglomerates. Data on the effect of filler particle size on nitrogen gas permeability will be present to demonstrate that a drop in permeability is obtained both with very large and very small particles. Also consistent with this qualitative picture is the finding that reduction in molecular weight during sonication of the polymer has minimal effect on the gas permeability of these matrices.
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Nanotech 2005 Conference Program Abstract