Comparison of partial discharge resistance among several biodegradable polymers

The partial discharge (PD) resistance of three kinds of biodegradable polymers, namely poly-L-lactic acid (PLLA), polybutylene succinate (PBS), and poly f-caprolactone butylene succinate (PCL-BS), was studied in comparison to that of low-density polyethylene (LDPE). The polymers were exposed to PDs under the IEC (b) electrode system, and the PD resistance was judged by the surface erosion depth or the time to breakdown induced by PDs. As a result, the 'practical' PD resistance, which is the resistance to PDs under a constant voltage application, is ranked as LDPE > PLLA >> PBS > PCL-BS, while the 'true' PD resistance, which is the resistance to PDs with a constant charge quantity, is ranked as PLLA = LDPE > PBS >> PCL-BS.