Exploring the influence of electron beam crosslinking in SEBS/TPU and SEBS-g-MA/TPU thermoplastic elastomer blends

The effects of electron beam (EB) radiation in thermoplastic elastomers based on SEBS/TPU and SEBS-g-MA/TPU are evaluated. 60/40 blend of both the systems were subjected to EB using an ILU type industrial accelerator. Radiation dose was varied from 0 to 100 kGy, and the sol–gel content evaluation along with detailed analysis of mechanical, thermal, rheological, and morphological implications was conducted. The interplay between crosslinking and chain scission was quantified using the Charlesby-Pinner equation. Both the blends showed the presence of a three-dimensional cross-linked network in them after the irradiation. The tensile strength of SEBS/TPU was found to deteriorate with an increase in radiation dose, but an opposite trend was observed in SEBS-g-MA/TPU. Improvement in interfacial adhesion between SEBS-g-MA and TPU was confirmed. The morphological analysis through atomic force microscopy and scanning electron microscopy clearly showed the appearance of rough ridges and pits due to irradiation along with the cross-linked networks. From differential scanning calorimetry analysis, the changes in glass transitions and melting endotherm were assessed. Thermogravimetric analysis results indicated an improvement in the thermal stability of the blends. The storage modulus and complex viscosity of the samples enhanced as perceived from the rheological measurements. X-ray diffraction patterns of the blends also showed considerable variation after irradiation.