2-COMPONENT INITIATOR SYSTEMS FOR THE RING-OPENING POLYMERIZATION OF OLIGOMERIC CYCLIC BISPHENOL-A CARBONATES - THE IN-SITU CLEAVAGE OF DISULFIDES BY TRIARLYPHOSPHINES

A two-component initiator system based on the in situ cleavage of phen yl disulfide by a triarylphosphine has been developed for the ring-ope ning polymerization of cyclic bisphenol-A (BPA) carbonate oligomers. T his development has potential use in composite applications such that the prepolymer can suitably wet the composite material before being co nverted to high-molecular-weight polymer. The initiator precursors (ph enyl disulfide and triphenylphosphine) do not independently initiate s ignificant ring-opening polymerization of the oligomeric cyclic BPA ca rbonate mixture. A mixture of cyclic BPA carbonate oligomers and one o f the initiator components (phenyl disulfide ), combined and heated at 300 degrees C with a mixture of the cyclics and the other initiator c omponent (triphenylphosphine), does produce a high-molecular-weight po lymer (M-w = similar to 70,000). The polymerization-initiating species is thought to be thiophenyltriphenylphosphonium thiophenoxide. The ef fects of concentration of the initiator components, reaction temperatu re, time, and so forth on polymerization were studied; in general, the degree of polymerization ranged from about 65 to 75%. (C) 1997 John W iley & Sons, Inc.