| 摘要 |
<p>Highly heat-resistant polymers containing repeating groups of formula: where R is a phenylene group, diphenylene group, diphenyl ether group, diphenylmethane group or naphthylene group, are prepared by (i) chlorinating condensed aromatic bis(2,4-dihydroxypyridine) derivatives of formula: in solution, (ii) oxyalkylating the chlorinated product with sodium or potassium alcoholate, (iii) decarboxylating the intermediate product in an aqueous alkaline or alcoholic solution, and (iv) carrying out simultaneous ring-closure and polymer formation in the presence of acids, at 20-300 deg.C., preferably 100-200 deg.C.</p> |
