Enhance Cell Nucleation on the Foam Structure by Using Nanoparticles

Cell density control in a foaming process is very important due to control of the foam properties. There are several methods to cell nucleation control. We used nanosilica and tried to control of prepared foam. Polystyrene/nanosilica nanocomposites with 1, 2, 4, 6, 8 and 10 weight percentage of nanoparticles made by using solution mixing method. Then the nanocomposites foamed at the saturation pressure of 20Mpa and the temperature of 120 °C in a high pressure autoclave. The addition of nanoparticles through heterogeneous nucleation and increase in cell density, increased cell density and decreased cell size at the produced foams. While nanoparticles amount increased from 0 to 6 wt. %, cell density of foam increased from 3.6*1012 to 4.5*1013 cell/cm3 and cell size decreased from 708 to 339 nm. The addition of nanosilica more than 6 wt. % resulted in reduction of cell density because of reduction in heterogeneous nucleation efficiency