THE INTERFACIAL POLYCONDENSATION OF TETRABROMOBISPHENOL-A POLYCARBONATE .2. REACTIVITIES AND PHASE DISTRIBUTION OF CATALYSTS

Tetrabromobisphenol-A (TBBPA), a sterically hindered bisphenol, is kno wn to give only low molecular weight polymers using the interfacial pr ocess. The low reactivity is attributed to the bulkiness and electron- withdrawing bromine substituents at the ortho positions. The optimum r eaction conditions for the interfacial polymerization of TBBPA using p yridine derivatives as a catalyst have been developed. From the two-ph ase concentration distribution constant (K(e)) and pK's values of trie thylamine, 4-dimethylaminopyridine (DMAP), and TBBPA, the critical pro cess parameters were obtained. Because of its high nucleophilicity and facile leaving character, the DMAP catalyst system produces a high mo lecular weight TBBPA-polycarbonate (PC) successfully. The profile of t he process was followed to obtain a better understanding of the reacti on mechanism. (C) 1993 John Wiley & Sons, Inc.