IMPROVED SYNTHESIS OF POLY(BENZOBISTHIAZOLE) POLYMERS

POLY [BENZO[1,2-D:4,5-D'] BISTHIAZOLE-2,6-DIYL)-1,4-PHENYLENE], XV ("TRANS" PBT) IS A LIGHTWEIGHT, NON-CONDUCTING, AROMATIC, HETEROCYCLIC ORDERED POLYMER THAT EXHIBITS EXCEPTIONAL MECHANICAL, THERMAL, CHEMICAL AND ELECTRO-OPTICAL PROPERTIES. HOWEVER, DEVELOPMENT OF "TRANS" PBT POLYMER INTO ADVANCED STRUCTURAL COMPOSITES HAS BEEN HINDERED BY THE LACK OF AVAILABILITY OF THE MATERIAL IN SUFFICIENT QUANTITIES FOR EVALUATION. THE OBJECT OF THIS PROPOSAL IS TO EVALUATE THE FEASIBILITY OF REPLACING "TRANS" PBT (XV) WITH "CIS" PBT POLYMER (XIV) IN THE DEVELOPMENT OF ORDERED POLYMERS. "CIS" PBT MONOMER (I) WILL BE SYNTHESIZED IN HIGH YIELD AND PURITY VIA SIMPLIFIED, MORE DIRECT ROUTES THAT ARE ECONOMICAL AND AMENABLE TO SCALEUP. HIGH MOLECULAR WEIGHT "CIS" PBT POLYMERS DERIVED FROM MONOMER I WILL FORM LIQUID CRYSTALLINE SOLUTIONS PROCESSABLE VIA SPECIAL TECHNIQUES INTO STRUCTURAL MATERIALS THAT EXHIBIT HIGH STRENGTH AND STIFFNESS AT ELEVATED TEMPERATURES. PHASE I OF THIS STUDY WILL DEMONSTRATE THE FEASIBILITY OF THE APPROACH. SUCCESSFUL COMPLETION OF PHASE I OBJECTIVES WILL HAVE PROFOUND INFLUENCE BEYOND THE SCOPE OF THIS STUDY, SINCE ORDERED PBT POLYMERS WILL BECOME READILY AVAILABLE VIA CONVENIENT, ECONOMICAL ROUTES, FOR DEVELOPMENT INTO USEFUL ARTICLES. PHASE II OF THIS STUDY WILL INCLUDE SCALE-UP OF "CIS" PBT POLYMER SYNTHESIS TO QUANTITIES SUFFICIENT FOR PROCESSING INTO BIAXIALLY-ORIENTED FILMS OF HIGH STRENGTH AND STIFFNESS.