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Microcellular PP vs. Microcellular PP/MMT Nanocomposites: A Comparative Study of Their Mechanical Behavior

Abstract Microcellular foams have attracted interest in both scientific and industrial communities. Injection molding is perhaps the most versatile industrial method of polymer processing. Microcellular injection molding is a newcomer variant in this class. It is capable to produce microcellular structure. The mechanical behavior of a microcellular polymer is different than conventional foams. Although they exhibit much improved mechanical properties than conventional foams still they are inferior to solid polymer. Incorporation of nanoparticles in matrix may affect the nucleation and bubble growth process. Further, nanoparticles will enhance the performance (stiffness, strength etc.) of matrix. In present study an effort has been made to quantitatively analyze the improvements in mechanical properties of microcellular foam with the addition of nanoclay (MMT). Nanocomposite of polypropylene and nanoclay was prepared in a co-rotating twin screw extruder. Maleic anhydride grafted polypropylene (PP-g-MA) was used as compatibilizer. PP/nanocomposites were foamed in a microcellular injection molding machine, where supercritical nitrogen (SCF-N2) was mixed with plasticized PP/nanocomposite inside the screw – barrel assembly. The molded foamed samples were tested for various mechanical properties. Experimental results show that a considerable improvement occur in the property of microcellular polypropylene by the addition of 2 wt.% nanoclay (MMT).