NANOSILICA FUNCTIONALIZATION FOR POLYPROPYLENE-BASED DIELECTRICS FACILITATING NEXT GENERATION HVDC TRANSMISSION

The presented thesis aims at developing of new types of insulation dielectric materials based on polymer nanocomposites for high-voltage DC cables. The DC grid network is rapidly developing across Europe and China, and this necessitates the design of new insulation polymer nanocomposites withstanding specific DC properties that vary significantly from common AC. Driven by the environmental pressure, green approach encourages us to find innovative solutions for the scientific and practical challenges in polymeric nanocomposites development. In this research work, polypropylene/elastomer blend is used as an insulation matrix due to its recyclability in opposition to commonly used cross-linked polyethylene. In addition, the plasma and solvent-free methods were successfully applied to modify the nanosilica filler surface, eliminating the environmental impact of waste solvent commonly used in suspension type of modifications. Nanodielectric polymer composites draw a lot of attention from both, industry and academia. It is reported that the polymer blend selection and the interface between a nanofiller surface and polymer matrix play an important role in improving the dielectric performance. This study focuses on the influence of the nanosilica surface functionalization on the micromorphology, dynamic and dielectric properties of the polypropylene based dielectric nanocomposites