Polypropylene Copolymers and Blends for HVDC Cable Insulation: Initial Characterization and Pilot-scale Production

This paper introduces a preliminary characterization of polypropylene-based copolymers as well as a possible ternary blend as a candidate to be used for HVDC cable insulation in the framework of the European project NEWGEN (New GENeration of HVDC insulating materials, cables and systems). The effect of production process scale-up (from mini-scale to pilot-scale cast-processing) is also investigated for the promising PP ternary blend which is essentially composed of homophasic PP random copolymer (RACO), heterophasic PP copolymer (HECO), and propylene-based elastomer (PBE). The preliminary dielectric characterization introduces a promising RACO/HECO/PBE blend with a similar and comparable performance of mini-scale and up-scaled specimens. Mechanical characterization show that incorporating HECO and PBE in the ternary blend reduces the stiffness metrics of RACO towards suitable values for HVDC cable applications.