Solid State NMR Characterization and Flammability of Styrene-Acrylonitrile Copolymer Montmorillonite Nanocomposite.
Solid State NMR Characterization and Flammability of
Styrene-Acrylonitrile Copolymer Montmorillonite
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.
copolymers; nonocomposites; solid state; flammability
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.