CURING KINETICS, THERMAL-PROPERTY, AND STABILITY OF TETRABROMO-BISPHENOL-A EPOXY-RESIN WITH 4,4'-DIAMINODIPHENYL ETHER

The curing reaction of tetrabromo-bisphenol-A epoxy resin (TBBPAFIR) w ith 4,4'-diaminodiphenyl ether (DDE) was studied by isothermal differe ntial scanning calorimetry (DSC) in the temperature range of 110-140 d egrees C. The results show that the isothermal cure reaction of TBBPAE R-DDE in the kinetic control stage is autocatalytic in nature and does not follow simple nth-order kinetics. The autocatalytic behavior was well described by the Kamal equation. Kinetic parameters, including 2 rate constants, k(1) and k(2), and 2 reaction orders, m and n, were de rived. The activation energies for these rate constants were 83.32 and 37.07 kJ/mol, respectively. The sum of the reaction orders is around 3. The glass transition temperatures (T(g)s) were measured for the TBB PAER-DDE samples cured partially in isothermal temperature. With the d egree of cure varies, different glass transition behaviors were observ ed. By monitoring the variation in these T(g)s, it is illustrated that the network of the system is formed via different stages according to the sequence reactions of primary and second amines with epoxides. It is due to the presence of the 4 bromine atoms in the structure of TBB PAER that this curing process can be clearly observed in DSC curves. T he thermal stability of this system studied by differential thermal an alysis-thermogravimetric analysis illustrates that the TBBPAER-DDE mat erial can automatically debrominate and takes the effect of flame reta rding when the temperature reaches 238.5 degrees C. (C) 1998 John Wile y & Sons, Inc.