Preparation and properties of isobutylene-isoprene rubber (IIR)/clay nanocomposites

Isobutylene-isoprene rubber/organic modified clay nanocomposites (IIRCN) were prepared by solution or melt intercalation (S-IIRCN or M-IIRCN), and the dispersion states of clay layers in these nanocomposites were investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). TEM images demonstrate that both exfoliated and intercalated nanoscale clay layers co-exist in these nanocomposites, and the aspect ratio of clay layers in S-IIRCN is larger than that in M-IIRCN. XRD patterns reveal that the basal spacing of clay increases from 2.2 nm for the original organically modified silicates to 4.2 nm for those dispersed in the composites, indicating intercalation of some rubber macromolecules into the galleries of clay layers. Compared with corresponding micro-composites and pure IIR vulcanizate, the prepared nanocomposites exhibit outstanding mechanical performances and improved gas barrier properties, which are likely attributed to the nanometer scale dispersion and high aspect ratio of clay layers. In addition, the properties of nanocomposites prepared by solution intercalation are somewhat superior to those of nanocomposites by melt intercalation. (C) 2004 Elsevier Ltd. All rights reserved.