Foaming of poly(methyl methacrylate) particles

Polystyrene based foams are currently the market benchmark for plastic rigid foam, but they present limitations when higher levels of mechanical or chemical resistance are required. A natural choice would be to obtain foams based on other polymers presenting improved properties and that could be produced by simple procedures such as poly(methyl methacrylate). In this work expandable poly(methyl methacrylate) particles (EPMMA) were obtained by suspension polymerization and their expansion behaviour was evaluated. Expansion only occurred in temperatures above 160 °C and the optimal temperature was 170 °C, in which the lowest specific weight was achieved without the formation of cell rupture. The expanded morphology of the EPMMA particles was compared to that of commercial expanded polystyrene, showing that the expanded structures are very similar regardless of the differences in the expansion method.