Physical Properties of Polypropylene Foams – how to Predict and Control Them

Low density extruded PP foams are increasingly being used in food packaging and automotive applications and their use is also being extended into other applications, such as insulation and protective packaging. This commercial success has been made possible by the development of HMS-PP, the unique physical property profile of PP itself and the ability modify the foam properties over a wide range by appropriate selection of a blend partner. It is the last factor that is the focus of the present paper. We will describe foaming studies using HMS-PP with different classes of polyolefin blend partner and different blowing agents. By combining this extensive experimental data with theoretical models, we are able to provide a predictive tool for selecting material combinations, which will enable the desired foam properties to be achieved by foam producers and end-users.