Corona resistance and dielectric strength of recycled PET-based composites

Thermoplastic composite materials are being used more and more in electronic and electrical applications, thanks to their processing advantages compared to thermoset composites as well as to the possible use of recycled materials. One possible application is for the mechanical support of the ignition system in internal combustion motors, and a good candidate for this application is reinforced polyethylene terephthalate (PET). In this study, the corona discharge resistance and dielectric breakdown strength of polymer composites based on recycled polyethylene terephthalate (PET) as a matrix and mica, carbon black and glass fibers as reinforcements were investigated for different composition (glass fiber and mica contain, size of the mica platelets) and different levels of surface quality resulting from different compounding procedures. Corona resistance was evaluated using a point-to-plane arrangement and the surface erosion was monitored by a mechanical profilmeter and scanning electron microscopy. Short time and step-by-step measurements were carried out to determine the breakdown voltage according to the ASTM-D149 standard. Temperature, thickness and other parameters affecting of endurance and dielectric breakdown strength were investigated and the results are presented and discussed in this paper.