Furthermore, we are also interested in reactive foaming, where polymerization and blowing occur simultaneously. Polyurethane (PU) foams are typical reactive foaming systems and make up over half of total foam market in the US alone. Substitutes for CFCS, such as pentane and water, have been used in an attempt to achieve the similar performance as CFCs but free from ODP . The PU foams blown by pentane or water, however, face many difficulties such as: 1) higher thermal conductivity than CFCs-blown foam , 2) high surface friability of water-blown foam due to polyurea formation, and 3) gradual cell deformation resulting from faster diffusion of gas in the cell through the cell wall than CFCs, thereby producing a larger pressure imbalance between foam cells and the atmosphere during the time needed for pressures and gas composition to equilibrate . These problems restrict their wide practical use.
We believe that polymer nanocomposites with good clay dispersion can provide a new method to control cell structure in reactively formed foams and also to improve matrix polymer properties of PU foam. The goal of this research is to is to develop a novel reactive foaming technology by combining nanocomposites and environmentally-benign blowing agents in a well-established manufacturing process. An exfoliated structure could be achieved by modified nanoclay with surface modifier with special
functional group. With the inclusion of 5% organoclay, smaller cell size and higher cell density of ODP-free PU foam can be achieved because nanoclay turns to nucleate bubbles and prevent coalescence. The dimensional stability of PU nanocomposite foam
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