Effects of comonomers and shear on the melt intercalation of styrenics/clay nanocomposites

The effect of polar comonomers introduced into polystyrene (PS) chains on t he melt intercalation into organosilicate is investigated in terms of shear and annealing time. In the case, where the interaction between polymers an d silicate layers is relatively weak, e.g. PS/organosilicate hybrids, it is difficult for the polymer chains to diffuse into interlayers of organosili cate and the hybrids are unstable under shear. For hybrids in which the int eraction is enhanced by incorporating polar comonomers, e.g. acrylonitrile (AN) and methylvinyl oxzoline (OZ), their structures are stable even after a long mixing time. However, they do not show an exfoliated structure under the mixing conditions used in this study. The interaction between the como nomer and the silicate surface is investigated indirectly via both X-ray di ffractional and FTIR spectral analyses. It is concluded that the structural stability of polymer/organosilicate hybrids is very dependent on the relat ive magnitude of the interactions between polymers, organic modifiers, and silicate layers. (C) 2000 Elsevier Science Ltd. All rights reserved.