Preliminary Study on Solid-State Foaming of PMMA/CNT Nanocomposites

Polymer nanocomposites with carbon nano tubes (CNTs) added in the polymer matrices have been shown to have improved material properties comparing to their neat forms. Foaming of polymer nanocomposites is even more interesting because these foams promise higher strength-to-weigh ratio and multifunctionality. However, many foaming results on polymer nanocomposites are inconclusive, for example, the effect of nano-additives on the bubble nucleation. In this study, solid-state foaming of pure PMMA and PMMA/CNT composite were performed. CNTs were dispersed in PMMA solution with ultrasonication. Microcellular foams were achieved in both cases. The resulted relative density and microstructures were investigated. It was found that nano carbon tubes aggregated on the cell walls of the microcellular foams. In terms of the cell size and relative density, there is no significant difference between pure PMMA and PMMA/CNT foams. Better dispersion of CNTs is needed in order to further study the CNT effect on the solid-state foaming process.