MORPHOLOGY AND CLASS TRANSITION BEHAVIOR OF POLYCARBONATE-PHENOXY SYSTEM - EFFECTS OF TRANS-REACTIONS IN DOMAIN INTERFACE REGIONS

Effects of trans reactions on the morphology, glass transition, and ph ase behavior in a classical blend system of a poly(hydroxyl ether bisp henol-A) (phenoxy) with bisphenol-A polycarbonate (PC) were investigat ed by differential scanning calorimetry (DSC) and optical microscopy. Although two T(g)s were observed in the as-prepared PC/phenoxy blends, an apparently single, but broadened, T-g was found in the blends afte r heating at high temperatures, typically 200-250 degrees C for short times. The optical microscopy results indicated that same scales of he terogeneity did exist in post-heated PC/phenoxy blends as well as unhe ated blends. Explanations were provided. After heating-induced interch ange reactions (-OH and carbonate), randomly linked polymer chains mig ht form at the numerous interfaces of the mutually occluded/included m icro-domains. The majority of the chains in the micro-domains are forc ed to relax in coordinated motion modes after heating, thus showing a single T-g. A mechanism of trans reactions in interfacial regions was briefly discussed in supplement to earlier reports in the literature. (C) 1997 John Wiley & Sons, Inc.