AC corona neutralization of positively and negatively charged polypropylene non-woven fabrics

The insulating materials can acquire high levels of electric charges, which are susceptible to generate electrostatic discharges. The present article aims at evaluating the efficiency of AC corona as neutralization mechanism for positively- and negativelycharged polypropylene non-woven fabrics. The samples were charged for 10 s, in ambient air, using a triode-type corona electrode system of positive polarity in the first set and negative polarity in the second set of experiments. In all experiments, the neutralization was performed 180 s after the charging process, with the samples moving at constant speed (3 cm/s) in the AC corona discharge zone generated by a dual-type corona electrode. The electric potential distribution at the surface of the samples was measured both before and after the neutralization. The experimental results show that the efficiency of neutralization depends on the amplitude and the frequency of the sinusoidal high-voltage that energizes the corona electrode. The negative charge proves to be more difficult to neutralize than the positive one.