The polyolefin and poly(ethylene terephthalate) (PET) products are the mostly current communal waste materials. The waste polymeric materials are generally difficult to separate, and therefore a processing of non-separated materials presents an interesting alternative suggestion. The aim of our work was to analyze the possibility of reprocessing of polyolefins by a relative low temperature, and to study the effect of addition of PET solid powder on processing and application properties. The results of our investigations allow to conclude that the solid PET powder may play a role of a heterogeneous nucleator, acting as an a-phase promoter of an isotactic polypropylene. (c) 2008 Wiley Periodicals, Inc.