Some observations on wool, paper, and polypropylene treated in a corona discharge

A study has been made of the transformation of some insulating materials exposed to corona discharges, including the role played by the atmosphere in which discharges are initiated. The resulting modifications are observed through a scanning electron microscope and the chemical changes are studied by means of infrared spectroscopy. In general, long exposure times were needed and the minimum time necessary to produce characteristic infrared absorption due to the effect of the discharges was selected. The action of the discharges on the bulk material has been studied as a function of time; the surface action of this discharge is both mechanical and chemical in nature.