Nemat J. Hossieny - Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto,۵ King’s College Road, Toronto, Ontario, Canada M۵S ۳G۸
Mohammadreza Nofar
Chul B. Park

The hard segments in thermoplastic polyurethanes (TPUs) are statistically distributed in the soft matrix phase. This distribution can be changed by processing the TPU material at various conditions such as melt processing or isothermal treatments. Furthermore, the hard segments contribute to the microcrystalline phase in TPUs. In this study, the foaming behaviour of as received and processed TPUs has been investigated using CO2 as a blowing agent. It was found that changes in the hard segment distribution caused by melt compounding affected the foam morphology. Comparing the Differential Scanning Calorimetry (DSC) thermographs of unfoamed as received with processed TPUs, it was observed that the processed TPU showed a broader endothermic peak suggesting a change in the hard segment length distribution. This broader hard segment length distribution showed an increase in the cell density of the processed TPU foams suggesting their contribution as a cell nucleation agent

Thermoplastic Polyurethane, Foam, Hard Segments