| Perfluorocyclobutyl (PFCB) aryl ether polymers refer to a general class of polyarylene ethers containing the PFCB repeating units. They can be prepared either by thermally induced [2pi+2pi] cyclodimerization of trifluorovinylether containing monomers above 150°C or by classic condensation polymerization using reactive 1,2-bis(aryl ether)hexafluorocyclobutyl monomers. Initially developed at The Dow Chemical Company and targeted for microelectronics applications, PFCB polymers have emerged as promising materials for polymer lightwave circuits, optics devices, separation membranes, fuel cell membranes, and composite matrix applications.; This dissertation focuses on the synthesis and development of functional perfluorocyclobutyl (PFCB) aryl ether polymers. First, the cyclodimerization of 4-(trifluorovinyloxy)benzoic acid was studied and the anomalous trans rich dimer obtained. In addition, a new nucleophilic addition reaction to aromatic trifluorovinyl ethers was studied, proving to be very efficient and potentially having great synthetic utility.; Second, two sets of PFCB polymers containing a phenylphosphine oxide (PPO) group in the main chain in one and as pendent group in the second were prepared for potential space applications. The polymer containing PPO groups in the backbone exhibited higher thermal stability. Copolymerization with bis(4,4'-trifluorovinyloxy)biphenyl (BP) afforded a high molecular weight film-forming transparent thermoplastic copolymers. Initial evaluations using ground-based simulation of atomic oxygen (AO) rich space environments indicated that the PPO group imparts significant space durability to PFCB polymers.; Third, a series of bis(trifluorovinylether) substituted oligophenylene monomers (n = 3,4,5) were synthesized and characterized. These compounds exhibit improved solubility and reduced melting points compared to their parent compounds. (Abstract shortened by UMI.)... |
