CHARACTERIZATION OF THE CURING BEHAVIOR OF CYANIC ESTER BY A POSITRON-ANNIHILATION LIFETIME TECHNIQUE

The curing process of a dicyanate resin system was investigated by a p ositron-annihilation lifetime technique (PA). Based on the observation of PA, it was shown that the size of free volumes of cured resins bec ame larger as the curing reaction proceeded. This result was supported by a change in the physical properties related to the size of free vo lumes, such as a decrease in the specific gravity, a decrease in the d ielectric constant and an increase in the water pick-up rate with incr easing the decree of the cure. It was therefore found that the curing reaction of dicyanate resin proceeded through a reaction of cyanate gr oups to form a larger size of free volumes. (C) 1998 Elsevier Science Ltd. All rights reserved.