Miscibility and cure kinetics studies on blends of bisphenol‐A polycarbonate and tetraglycidyl‐4,4′‐diaminodiphenylmethane epoxy cured with an amine

Abstract Differential scanning calorimetry (DSC) has been applied to characterize the glass transition behavior of the blends formed by bisphenol‐A polycarbonate (PC) with a tetrafunctional epoxy (tetraglycidyl‐4,4′‐diaminodiphenyl methane, TGDDM) cured with 4,4′‐diaminodiphenylsulphone (DDS). A rare miscibility in the complete composition range has been demonstrated in these blends. Additionally, the blend morphology was examined using scanning electron microscopy (SEM) and a homogeneous single‐phase PC/epoxy network has been observed in the blends of all compositions. Moreover, polycarbonate incorporation has been found to exert a distinct effect on the cure behavior of the epoxy blends. The cure reaction rates for the epoxy‐PC blends were significantly higher due to the presence of PC. In addition, the cure mechanism of the epoxy blends was no longer autocatalytic. An n ‐th order reaction mechanism with n = 1.2 to 1.5 has been observed for the blends of DDS‐cured epoxy with PC of various compositions studied using DSC. The proposed n ‐th order kinetic model has been found to describe well the cure behavior of the epoxy/PC blends up to the vitrification point. © 1995 John Wiley & Sons, Inc.