Specific interaction governing the melt intercalation of clay with poly (styrene-co-acrylonitrile) copolymers

In the melt intercalation of cation-exchange clay, mixtures of montmorillon ite and poly(styrene-co-acrylonitrile) (SAN) with various acrylonitrile con tents were studied to examine the effect of specific interaction. When orga nic molecules with hydroxyl groups were used as intercalants for the clay, the amount of SAN penetrating the gallery of the layered structure of the c lay and the corresponding increase in the gallery height occurred at a much higher rate because of the attractive specific interaction between acrylon itrile groups and polar groups on the clay surface. However, there was a li mit to the increase in the gallery height, and the tendency for the gallery height to increase with the acrylonitrile group content disappeared when t he acrylonitrile content was greater than 30 wt %, implying that excessive attractive interaction on the clay surfaces and polymer molecules glued the two adjacent silicate layers together; consequently, the increase in the g allery height could not be accomplished. (C) 2001 John Wiley & Sons, Inc.