Date of Award
Spring 2005
Document Type
Dissertation - Restricted
Degree Name
Doctor of Philosophy (PhD)
Department
Chemistry
First Advisor
Sem, Daniel S.
Second Advisor
Steinmetz, Mark G.
Third Advisor
Wilkie, Charles
Abstract
This research mainly focuses on the preparation, characterization and applications of polymer layered clay nanocomposite. Chapter 1 gives a brief introduction on the preparation of polymer clay nanocomposite and test methods used to determine the nanostructure, thermal stability and flame retardancy. Chapter 2 through Chapter 7 studied the preparation of polymer-layered clay nanocomposite by melt blending with different oligomerically modified clays, which include polycaprolactone, polystyrene copolymer or terpolymer and poly (methyl methacrylate) copolymer. These nanocomposites were evaluated by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, cone calorimetry and mechanical properties. The results show that polycaprolactone-modified clay can give a completely exfoliated nanocomposite when a clay which contains hydroxyl functionality is used while either immisible or intercalated nanocomposite are formed when the starting clay does not contain functional groups on the ammonium cation; the incorporation of phosphate as a component of an oligomeric ammonium salt modified clay nanocomposite gives a large reduction in the peak heat release rate, suggesting this system has potential for the formation of fire retardant polymeric systems. Maleic anhydride modified clay improves the compatibility between the clay and polystyrene, while high and low molecular weight oligomerically-modified clay only has an effect on the mechanical properties and there is no effect on the other properties. A methyl methacrylate oligomerically modified clay shows mixed intercalated/exfoliated morphology depending on polymer nature; it has good compatibility with poly (methyl methacrylate) and high impact polystyrene, but not with acrylonitrile-butadiene-styrene terpolymer, polypropylene, or polyethylene. Chapter 8 is some suggestions of future work based on this study.