PLASTIC FOAMS BASED ON CHLORINATED POLYMERS

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.