Charge decay and space charge in corona-charged LDPE

The surface charge decay and space charge distribution in corona-charged low-density polyethylene (LDPE) were investigated. The space charge distribution was measured at 30/spl deg/C with the pulsed electro-acoustic (PEA) method, where a corona charged specimen was set between a semiconductive electrode and an Al electrode. The space charge distributions in LDPE were quite different between corona charging and DC voltage charging. They also depended on the kind of low-density polyethylene, LDPE polymerized with the high-pressure process and m-LDPE polymerized with metallocene catalysts. The surface charge decay of corona-charged polyethylene is slower for m-LDPE than for LDPE. Especially, positive charge is very stable for m-LDPE. These results were discussed considering the morphology of polyethylene.