Polymer Nanocomposite Foams
Polymeric foam utilizing nanoclays in the polymeric matrix.
Various polymeric foams, such as polyvinyl chloride foam (PVC), polyurethane foam, polyimide foam, Styrofoam, etc., are used to manufacture components for insulation, plumbing, adhesives, and duct work. Currently available polymeric foams carry a considerable amount of health and safety risks, and most have been designated as regulated carcinogens by many governmental agencies, including the FDA and EU Risk Assessment Commission. Additionally, these substances carry safety concerns ranging from high flammability to degradation resulting in structural instability. There is a need to develop polymeric foams that maintain the material properties of currently available products and mitigate health and safety concerns.
Researchers at The Ohio State University, led by Dr. L. James Lee, developed polymeric nanocomposite foams and a method of formation. Nano-sized particles such as nano-clays can be mixed with polymers through either melt compounding or in-situ polymerization. By modifying the particle surface with various surfactants and controlling processing conditions Dr. Lee was able to achieve either intercalated (partial dispersion) or exfoliated (full dispersion) nano-clay distribution in polymers with the clay content up to 35% by weight. When a blowing agent is injected into the nanocomposite in an extruder (a continuous mixer) or a batch mixer, polymeric foam can be produced. Supercritical carbon dioxide, an environmentally friendly, low-cost, non-flammable, chemically benign gas is used as the blowing agent. Foamed polymers are advantageous in a number of industries such as packing, insulating, and tissue engineering.