ISOTHERMAL CURING OF AN UNCATALYZED DICYANATE ESTER MONOMER - KINETICS AND MODELING

The isothermal cure of a dicyanate ester monomer has been studied unde r different atmospheres (air and argon) without any catalyst, by follo wing the evolutions of both glass transition temperature and conversio n. Independently of both atmosphere and temperature of cure, there is a unique one-to-one relationship between these two parameters, correct ly described by a restated DiBenedetto's equation. The chemical kineti cs are satisfactorily modeled with two competing reactions schemes, wh ich are second-order and second-order autocatalyzed, the latter displa ying more relative importance under air-curing conditions. Whatever th e cure temperature may be, gelation occurs around 0.60 conversion unde r air, whereas the theoretical x(gel) = 0.50 is experimentally observe d under argon. The time-temperature-transformation diagrams have been established. (C) 1993 John Wiley & Sons, Inc.