The present authors have already reported that barium oxide is the mos
t effective catalyst for the conversion of waste polystyrene into styr
ene including both monomer and dimer. Around 85 wt. % of waste polysty
rene was converted into styrene when it was degraded at 623 K in the p
resence of barium oxide as catalyst. In this paper, the preparation an
d the thermal degradation of polystyrene films with dispersed catalyst
are described for a design of recyclable plastics for better environm
ent. More than 85 wt. % of the films was degraded into styrene at 623
K without addition of other catalytic compounds. Techniques for foamin
g the films using either nitrogen or carbon dioxide are discussed. It
was found that the polystyrene foams with dispersed catalyst are well
converted into styrene when they are simply degraded at 673 K.