This article discusses the development of microcellular HDPE and HDPE—clay nanocomposites via a batch high temperature process using supercritical N 2. The study incorporates the effects of clay content and nanocomposite microstructure on the foaming process performance and cellular morphology under investigation. It was possible to produce much nucleated and more expanded microcellular foams with the nanocomposites than with the pure HDPE, as over 14 vol% void fraction could be reached at 6 wt% clay containing nanocomposite as a good result for foaming by N2 gas via a batch foaming process. We found that the state of nanoparticle dispersion affects the microcellular morphology, so a better dispersed nanocomposite results in a more nucleated system in the microcellular foaming process. Moreover, the relationship between crystalline morphology and cell structure was investigated. Crystallinity and melting point were the important parameters for controlling the cell growth mechanism in this foaming method.
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