The present invention is directed to a method for preparing a polymer for chemical mechanical polishing of a semiconductor substrate. The method comprises providing a thermoplastic foam substrate and exposing the substrate to an initial plasma reactant to produce a modified surface thereon. The method also includes exposing the modified surface to a secondary plasma reactant to create a grafted surface on the modified surface. An electrode temperature is maintained between about 20° C. and about 100° C. during the exposures of the substrate and the modified surface.