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Solid State NMR Characterization and Flammability of Styrene-Acrylonitrile Copolymer Montmorillonite Nanocomposite.


pdf icon Solid State NMR Characterization and Flammability of Styrene-Acrylonitrile Copolymer Montmorillonite Nanocomposite. (1215 K)
Bourbigot, S. P.; Vanderhart, D. L.; Gilman, J. W.; Bellayer, S.; Stretz, H.; Paul, D. R.

Polymer, Vol. 45, No. 22, 7627-7638, October 2004.

Keywords:

copolymers; nonocomposites; solid state; flammability

Abstract:

This work investigates the melt-processing of styreneDSacrylonitrile copolymer (SAN) with organo-modified montmorillonite (MMT) clays and the influence of the clay on mechanical properties and on fire performance of SAN. The nanodispersion of MMT is evaluated qualitatively by X-ray diffraction (XRD) and transmission electronic microscopy (TEM), and quantitatively by solid state nuclear magnetic resonance (NMR). SAN/MMT nanocomposites reveal an intermediate morphology, an intercalated structure with some exfoliation and with the presence of small tactoids, whatever the loading in MMT is. The polymer-clay interfacial area is estimated at 0.5 and the degree of homogeneity characterizing the distribution of MMT platelets is about 40%. The presence of clay in SAN-25 leads to a "filler effect" increasing the stiffness but decreasing tensile strength of the nanocomposites. It also leads to a significant decrease of peak of heat release rate measured by mass loss calorimetry.