Journal of Advanced Materials in Engineering (Esteghlal)

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This research aimed at producing microcellular foams (with cell size of 1-10 μm and cell density above 10 9 cell/cm3) from PC/EPDM in order to use in medical devices. Due to the weak nucleation behavior of microcellular polycarbonate foams, it is difficult to prepare them. This research provides valuable information regarding the possibility of making microcellular foams from this polymer by using multiwalled carbon nanotubes (MWNT,s) as nucleating agents (the value of 1-3 phr). The nanocomposite samples were prepared in an internal mixer and foamed via a batch processing method using supercritical carbon dioxide as the foaming agent. The results showed that the addition of nanoparticles up to 3 phr improves the foamability of PC/EPDM blend. Furthermore, as nanoparticle content increased a decrease in cell size and hence an increase in cell density were observed. Another finding showed that cell size distribution is directly related to uniform dispersion of carbon nanotubes.

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In this study, aluminium composite foams reinforced by different volume fractions of SiC particles as reinforcement and stabilizing agent were fabricated with the direct foaming route of melt using different contents of CaCO₃ as foaming agent. The density of produced foams were measured to be from 0.38 to 0.68 g/cm³. The microstructural features and compressive properties of the AA356/SiC_p composite foams were investigated. The relation between plateau stress, density and, weight percentage of CaCO₃ and SiC_p volume fraction with a given particle size was also investigated. The results showed that compressive stress-strain curves of the products were not smooth and exhibit some serrations. Also, it was shown that in the same density of composite foams, the plateau stress of the composite foams increases with increasing volume fraction of SiC particles and decreasing weight percentage of CaCO₃.