Preparation and thermal properties of epoxy resins from diaminodiphenylsulfones

Abstract

Two epoxy resins were synthesized by glycidylation of two diamino compounds 3,3``-and 4,4``-diaminodiphenyl sulfone (DDS) and spectroscopically characterized. The resins prepared were then cured with curing agent of 3,3``-DDS, 4,4``-DDS and 4,4``-diaminodiphenyl methane (DDM). For the curing reactions cure kinetics was investigated by measuring enthalphy changes at constant temperature of $140\,^\circ\!C,\; 170\,^\circ\!C$ and $200\,^\circ\!C$. In order to study an effect of curing agent content upon the Tg values, the epoxy resins containing various amounts of curing agents were cured for one hour at $140\,^\circ\!C$ and then for 5 hours at $170\,^\circ\!C$, and the Tg values of the cured epoxy resins were determined. These Tg changes with curing agent content were discussed and compared with the DDM-derived epoxy resin/4,4-DDS system which is very widely applied in carbon fiber prepreg industry.