Synthesis of poly(phenylquinoxaline)s via self-polymerizable quinoxaline monomers

The development of three new self-polymerizable quinoxaline monomers was pu rsued in an attempt to increase the susceptibility of the monomers toward a romatic nucleophilic substitution reactions. The polymerizations were carri ed out in N-methyl-2-pyrrolidinone in the presence of potassium carbonate, to yield high molecular weight poly(phenylquinoxaline)s (PPQs). Replacement of the 1,4-phenylene group of the phenol in the isomeric monomer mixture o f 2-(4-hydroxyphenyl)-3-phenyl-6-fluoroquinoxaline and 3-(4-hydroxyphenyl)- 2-phenyl-6-fluoroquinoxaline with the 2,6-naphthylene, 4,4 ' -biphenylene, and 4,4 ' -oxydiphenylene groups resulted in more reactive monomers as evid enced by shorter polymerization times and lower polymerization temperatures needed to obtain PPQs with high intrinsic viscosities. Polymerizations of the 1,4-phenylene-, 2,6-naphthylene-, 4,4 ' -biphenylene-, and 4,4 ' -oxydi phenylene-containing monomers led to PPQs with intrinsic viscosities rangin g from 1.4 to 2.5 dL/g and glass transition temperatures ranging from 221 t o 287 degreesC. All of the PPQs exhibited high tensile properties, with ten sile strengths of greater than or equal to 92 MPa, tensile moduli of greate r than or equal to2.6 GPa, and elongations of greater than or equal to 88%.