The interfacial polycondensation of tetrabromobisphenol-A polycarbonate. II. Reactivities and phase distribution of catalysts

Tetrabromobisphenol‐A (TBBPA), a sterically hindered bisphenol, is known to give only low molecular weight polymers using the interfacial process. The low reactivity is attributed to the bulkiness and electron‐withdrawing bromine substituents at the ortho positions. The optimum reaction conditions for the interfacial polymerization of TBBPA using pyridine derivatives as a catalyst have been developed. From the two‐phase concentration distribution constant (Ke) and pK's values of triethylamine, 4‐dimethylaminopyridine (DMAP), and TBBPA, the critical process parameters were obtained. Because of its high nucleophilicity and facile leaving character, the DMAP catalyst system produces a high molecular weight TBBPA–polycarbonate (PC) successfully. The profile of the process was followed to obtain a better understanding of the reaction mechanism. © 1993 John Wiley & Sons, Inc.