SAXS Analysis of Polypropylene-Layered Silicate Nanocomposites: An Integrated Correlations Functions Approach Using an Exfoliation Factor
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Title |
SAXS Analysis of Polypropylene-Layered Silicate Nanocomposites: An Integrated Correlations Functions Approach Using an Exfoliation Factor
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Creator |
RASHEED, ASA
PRESCHILLA, N SIVALINGAM, G TYAGI, S BISWAS, A BELLARE, JR |
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Subject |
x-ray-scattering
small-angle scattering interface distribution functions lamellar 2-phase systems isotactic polypropylene polymer nanocomposites linear polyethylene crystallization morphology poly(ethylene-terephthalate) nanocomposites small angle x-ray scattering correlation function |
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Description |
Use of correlation function and interface distribution function to obtain the morphological parameters from Small Angle X-ray Scattering data makes it as an important quantitative method to evaluate lamellar morphology. Analysis using correlation function assumes lamellar stack morphology with variation of electron density along one dimension where lateral width of lamellae is much larger than the long period normal to the lamellae and the electron density varies with a rectangular profile for alternating crystalline and amorphous layers. In this work, a modified Porod law approach is used for the deviation from ideal two phase model and the thickness of transition zone with variation in electron densities is calculated. Morphological parameters of various grades of organically modified Polypropylene clay nanocomposites, such as long period, linear crystallinity, lamellar thickness and amorphous thickness are estimated using a combination of correlation and interface distribution function. Presence of transition zones does not influence the values for amorphous layer thickness, crystalline layer thickness and long period. Variations in values of long period calculated from correlation and interface function suggest a distribution of lamellar sizes in the polymer and nanocomposites. A new model consisting of the integrated correlation function of polymer and organoclay was developed to quantify the extent of exfoliation of organoclay in the nanocomposites by introducing a parameter, the exfoliation factor, P. For a highly non-exfoliated system, the large number of clay tactoids is highly correlated and interacting, the correlation function of nanocomposites will be similar to that of nanoclay samples with low values of exfoliation factor. The correlation function of well exfoliated nanocomposites is similar to neat polymer, and such systems have high values of the exfoliation factor. Moreover, the exfoliation factor, which is easily determined by a scattering experiment, correlated well to the important engineering properties of the nanocomposites.
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Publisher |
AMER SCIENTIFIC PUBLISHERS
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Date |
2011-07-17T03:44:20Z
2011-12-26T12:50:06Z 2011-12-27T05:36:05Z 2011-07-17T03:44:20Z 2011-12-26T12:50:06Z 2011-12-27T05:36:05Z 2009 |
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Type |
Article
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Identifier |
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, 9(8), 4948-4960
1533-4880 http://dx.doi.org/10.1166/jnn.2009.1272 http://dspace.library.iitb.ac.in/xmlui/handle/10054/4606 http://hdl.handle.net/10054/4606 |
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Language |
en
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