Crystallization behavior of syndiotactic polystyrene nanocomposites for melt- and cold-crystallizations

Analyses of the effects of montmorillonite (clay) on the crystallinity and crystallization behavior of syndiotactic polystyrene (s‐PS) were investigated by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The dispersibility of the clay in s‐PS nanocomposites was studied by X‐ray and transmission electron microscopy (TEM). The clay was dispersed into the s‐PS matrix by melt blending on a scale of 1–2 nm or few tenths–100 nm, depending on the surfactant treatment. On adding clay, the crystallization behavior of the s‐PS tends to convert into the β‐crystal from the α‐crystal after being cold‐crystallized because the clay plays a vital role in facilitating the formation of the thermodynamically favored β‐form crystal when the s‐PS is cold‐ or melt‐crystallized. This phenomenon leads to a change in a conventional mechanism of molecular packing for the s‐PS. Evidently, the clay significantly affects the crystallinity and crystallization behavior of the s‐PS. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2492–2501, 2002