Properties of bead foams with increased heat stability made from the engineering polymer polybutylene terephthalate (E-PBT)

Abstract

Bead foams from the standard polymers polystyrene (EPS) and polypropylene (EPP) are widely established in many applications but possess a rather low heat stability. Currently other polymers such as engineering and high temperature polymers get more and more in the focus of research. For instance, bead foams made from polybutylene terephthalate (E-PBT) are able to withstand a higher thermal load. In the current study the mechanical behavior of this new material is described. Tensile tests showed, that E-PBT and EPP, have a similar Young's modulus. Judged on the fracture surface a good bead fusion can be achieved for E-PBT as predominantly trans-bead fracture occurs. Within this work it could be shown that E-PBT possesses a higher compressive strength compared to EPP, especially at elevated temperatures up to 150 °C. Furthermore, the burning behavior was evaluated revealing that E-PBT ignites later and in case of fire it releases less heat compared to EPP.