Abstract
The propagating free radicals of self-curing resin for rebasing were examined by the electron spin resonance (ESR) technique. At 37℃, the propagating radical was first detected 5.5 minutes after mixing. The concentration of free radicals increased rapidly with time after 'so-called' induction time and reached the maximum level at 27 minutes. The free radicals thus formed were stable for more than 3,656 minutes, though the amount diminished gradually. With increased curing temperature, the maximum level of radical concentration decreased and the residual free radicals disappeared more rapidly. Radical concentration increased with an increase in the amount of activator of N, N-dimethyl-p-toluidine. The free radicals remained stable longer when mixed with a liquid containing less inhibitor of hydroquinone.
