It has been observed in the production of polypropylene nanocomposites containing silicate materials that the molecular weight of the polymer used can have a significant effect on the final quality of the composites. The availability of polypropylene over a range of molecular weights with similar material properties (e.g. melting temperature and tacticity) is limited. Therefore, the ability to use a single catalyst system to generate polypropylene with a range of molecular weights is an attractive goal. In this contribution the use of styrene as a chain-terminating agent is explored, in order to produce materials with a range of molecular weights from a single catalyst system. It is found that the molecular weight of the polypropylene produced can be varied in the range from 120 000 to 9000 g mol(-1) using the Me(2)Si(Ind)(2)ZrCl(2)/methylaluminoxane catalyst system. (C) 2011 Society of Chemical Industry