Heat Stable Polyquinoxalines. Heat Stable Polymers: Polyphenylene and Other Aromatic Polymers.

Linear thermally stable polyquinoxalines have been prepared by the reactions of combinations of three tetraamines, with two bisglyoxals. All the polyquinoxalines have excellent thermal stability both in nitrogen and in air. Ladder quinoxaline polymers were prepared by the condensation of aromatic tetraamines or tetraketones. All of the polymers obtained were completely soluble in 1,3-dichloro-1,1,3,3-tetrafluoro-2,2-dihydroxypropane. The thermal stability of the ladder polymers in a nitrogen atmosphere was considerably greater than that of the corresponding single-strand polymer. The Diels-Alder reaction of cyclopentadienones or alpha-pyrones with acetylene dienophiles provides a unique and unequivocal method of synthesis of polyphenylenes. High molecular weight 60-100,000 phenylated polyphenylenes and polyp-phenylene can be obtained from this reaction. The Diels-Alder homopolycycloaddition of 2,5-diphenyl-3,4-5,6-acenaphthylenylenecyclopentadienone afforded a low molecular weight soluble ladder polymer. Modified author abstract