Study on the superoxide radicals of PU surface radiated by plasma with the 2,2,6,6-tetramethyl-1-piperidinyloxyl radical method

In this study, the quantity of the superoxide radicals created by O2 plasma activation was confirmed by a new method-the 2,2,6,6-Tetramethyl-1-piperidinyloxyl radical (TEMPO) method and the effects of various conditions on radicals concentration were investigated. Under the conditions at which the radicals have optimal concentration, polyurethane (PU) film was treated by plasma to graft with Acrylic acid (AA) in order to testify the feasibility and dependability of the TEMPO method. In addition, the influences of react conditions on grafting rate were discuss, the acrylic acid grafted on the surfaces was characterized by Scanning electron microscopy (SEM). At 600W, 180s the concentration of the radicals high, the grafting rate is high correspondingly. The results suggest that the TEMPO method is an effective method to determine the concentration of superoxide radicals. (authors)