Unique SAN / layered silicate nanocomposites formed by melt intercalation
Lloyd Goettler, Phaniraj Nagaraj
The University of Akron
U.S.A

Keywords: SAN nanocomposites, melt intercalation, polarity

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Styrene co-acrylonitrile (SAN) provides an ideal polymer matrix for layered silicate nanocomposites. Its polarity can be adjusted through the copolymer composition, while it can be reinforced and potentially toughened by nanoscale clay platelets without loss of its inherent transparency.
Among the factors governing polymer intercalation of clay layers, the polarity level and polarity match between the polymer and the treated clay surface are predominant. The objective of this work is to analyze the effect of polar groups on nanocomposite formation and to determine the role of specific interactions between the polymer and the layered silicate on nanocomposite performance. The hydrophilic acrylonitrile content of the SAN is varied in order to manipulate its polarity and consequently its compatibility with the organoclay. Different SAN copolymers with varying acrylonitrile contents are combined with several clay types to prepare a range of nanocomposite compositions. The resulting melt-intercalated structures are characterized by X-ray diffraction, TEM, DSC, TGA, tensile testing and rheology and interpreted according to the thermodynamics of mixing.