Extensional rheology and CO₂ foaming of thermoplastics vulcanizates: Influence of the crosslinking chemistry

The objective of this study is to investigate the ability thermoplastic vulcanizates (TPVs) (materials based on PP/EPDM blend) foam under CO 2 batch conditions. EPDM phase, which dispersed into PP was dynamically crosslinked either by a phenolic resin (Resol) or radical peroxide (dicumyl peroxide). results show an influence crosslinking chemistry extensional viscosity TPV. Regarding chemistry, induces polypropylene degradation β-scission reaction during dynamic process. As result, TPV deform flow (Hencky deformation at break <0.5) greatly reduced. On contrary, Resol-based has demonstrated non-linear behaviour (strain hardening) and great >1.5). This unexpected result for non-homogeneous system can be explained confinement phase between nodules gives chains gel rheological behaviour. In addition, addition carbon black filler also been studied. Finally, relationship physical foaming investigated. homogeneous polymer, proved key factor estimate complex systems like Hence, importance multi-phasic polymer ensure demonstrated.