Journal of Applied Polymer Science, Vol.70, No.10, 1991-2000, 1998
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) with 4,4'-diaminodiphenyl ether (DDE) was studied by isothermal differential scanning calorimetry (DSC) in the temperature range of 110-140 degrees C. The results show that the isothermal cure reaction of TBBPAER-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 derived. 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 TBBPAER-DDE samples cured partially in isothermal temperature. With the degree of cure varies, different glass transition behaviors were observed. 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 TBBPAER that this curing process can be clearly observed in DSC curves. The thermal stability of this system studied by differential thermal analysis-thermogravimetric analysis illustrates that the TBBPAER-DDE material can automatically debrominate and takes the effect of flame retarding when the temperature reaches 238.5 degrees C.