The global demand for the polymeric foams especially Polypropylene (PP) foams is increasing rapidly. Some industrial processing of the PP foam need high processing temperature. But, there are only a few research has been done on high temperature processing as the quality of foam deteriorates in that condition. Moreover, Physical Blowing Agents (PBA) need additional accessories to process the foam. But usually industries are reluctant to change their existing system to get foamed output initially. This thesis develops an approach to manufacture PP foams with Chemical Blowing Agents (CBA) in high temperature extrusion. In the first step, a series of fundamental studies have been carried out by investigating the effect of different chemical blowing agent and content, pressure drop rate and residence time on the foaming behavior of polypropylene. And then, optimized parameters are applied and the combination effect of CBA-PBA and the effect of nucleating agents has been examined.