Physical adsorption of organic molecules on the surface of layered silicate clay platelets: A thermogravimetric study

Physical adsorption of various adsorbents on the surface of premodified montmorillonite platelets was performed to fully organophilize the inorganic platelets for the purpose of their easy nanoscale dispersion in the polymer matrices during compounding. Different extents of adsorption could be achieved owing to the nature and the functionality of the adsorbents. High molecular weight adsorbents not only enhanced the organic coverage of the platelets but also were observed to contribute toward the thermal stability improvement of the organic modification, thus further fitting the use of such clays for high temperature compounding. The amount of adsorption could also be quantified with respect to the initial amount of adsorbent used in the process. The importance of a clean surface free from any excess surface modification or adsorbent molecules was emphasized. The adsorption process is an effective means to generate such high potential montmorillonites and is much simpler in technique than the common methods of grafting of polymer chains from the clay surface.

TGA thermogram of the organically modified montmorillonite (I) adsorbed with varying amounts of poly(vinylpyrrolidone) (II and III).Figure optionsDownload as PowerPoint slide