© Smithers Rapra Technology, 2011 187 Cellular Polymers, Vol. 30, No. 4, 2011 Mechanical Properties and Morphology of Multifunctional Polypropylene Foams Mechanical Properties and Morphology of Multifunctional Polypropylene Foams M. Antunes * , V. Realinho, M. Ardanuy, M.Ll. Maspoch and J.I. Velasco Centre Català del Plàstic. Universitat Politècnica de Catalunya. C/ Colom 114, E-08222 Terrassa, Barcelona, Spain SUMMARY One of the actual trends in polymer foams consists in the development of new materials by combining density reduction through foaming with the incorporation of functional fillers. This would enable to obtain materials with improved specific properties and added functionalities. There is also a growing interest in the use of environmentally-friendly materials obtained from renewable sources, thus coming as a logical step to combine both in order to create novel biocomposite foams. This work presents an overview of our recent results regarding the preparation and structural and thermo-mechanical characterizations of rigid polypropylene-based composite foams, with the main goal of developing new lightweight materials with tailor-made properties (multifunctional foams). Several reinforcements have been considered, from renewable cellulose fibres to nanometric-sized reinforcements such as silicate-layered nanoclays and carbon nanofibres. 1. INTRODUCTION One of the main key challenges regarding polymer materials lies in the development of increasingly lighter components with improved specific properties to be used in demanding applications [1-2]. A possible strategy combines the weight reduction from foaming the base material with the incorporation of reinforcements and/or functional fillers. Alongside improvements in stiffness and mechanical strength, considerably reduced by the incorporation of a high gas volume fraction, their addition could * Corresponding author: marcelo.antunes@upc.edu. Tel: +34 93 783 70 22; Fax: +34 93 784 18 27