Acetylene Terminated Sulfone Resin Precursors of Tailored Length via a Modified Ullmann Ether Synthesis

摘要

Air Force sponsored research in recent years has been directed toward the discovery and development of new composite resins which would display all of the advantages of epoxy resins, but without the moisture sensitivity problem. One of the first resins to show such potential was the AT resin, 4,4'-bis(3-ethynylphenoxy)-phenylsulfone (ATS). Its initial limitation, however, was very high cost. As a result, of contractual research for the Air Force at Gulf Research and Development Company, a new, low cost synthesis approach to ATS was developed. the Ullmann ether reaction of 4,4'-sulfonyl with 1,3-dibromobenzene was carried out in 2,4,6-collidine with cuprous oxide to afford high yields of a mixture of 4,4'-bis(3-bromophenoxy)phenylsulfone (BPDS) and its associated oligomers (OBPDS). This mixture is a low-cost precursor to the ATS composite resin system, formed by replacing the bromine atoms by terminal acetylene groups. The ratio of BPDS to OBPDS was found to be tailorable by varying stoichiometry, permitting selection of average ATS oligomer length for desired balances between processing and mechanical properties.