Investigation of Dielectric and Thermal Properties of iPP/MA-PP/TPU Blends

Isotactic polypropylene (iPP)-based blends have been widely investigated for their potential as next-generation insulating materials for high voltage cables. Pure iPP is too brittle; hence, blends with various elastomers have been developed. In the present work, maleic anhydride grafted polypropylene (MA-PP) is used as a compatibilizer, enhancing its compatibility with thermoplastic polyurethane (TPU) elastomer in an attempt to prepare and characterize iPP/MA-PP/TPU blends. This study investigates the thermal properties, molecular structure, and dielectric performance of these blends using differential scanning calorimetry (DSC), Fourier-Transform Infrared (FTIR) spectroscopy, and dielectric spectroscopy (DS). The results reveal that the introduction of maleic anhydride (MA) into the blends results in the formation of imide structures, through crosslinking with the TPU, that do not affect the crystallinity and melting point of iPP. The iPP/MA-PP/TPU blends display increased dielectric permittivity and losses in the low frequency domain; characteristics that are dependent on the concentration of MA.