Plastic foams based on chlorinated poly(vinyl chloride) (PVC), polyeth
ylene and natural rubber were prepared by using the pentane impregnati
on technique, which is commonly applied to polystyrene. The chlorinate
d polymer powders were obtained by an original chlorination process in
dichloromethane, which can be applied to all used polymers, followed
by an emulsion-precipitation process. Before foaming, the polymer powd
ers had to be processed by extrusion. The prepared granules were impre
gnated with pentane in an autoclave and then transformed into foam bea
ds in boiling water. In a subsequent process, the beads were transform
ed into foamed cubes. The non-inflammable plastic foams are characteri
zed by a small density of less than 0.1 g cm(-3). Compared with polyst
yrene, the plastic foams based on the chlorinated PVC are more rigid.