Synthesis and Properties of Aromatic Polyamides and Polyimides from 9, 10-Dihydro-9,10-o-benzenoanthracene-1,4-diamine

Abstract

Aromatic polyamides and polyimides were synthesized from 9,10-dihydro-9,10-o-benzenoanthracene-1,4-diamine (2,5-triptycenediamine). Aromatic polyamides were synthesized by the low-temperature solution polycondensation, whose inherent viscosities were 0.67—1.68 dl g−1. The polyamide from isophthaloyl dichloride was soluble in dimethylacetamide (DMAc), 1-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylsulfoxide (DMSO), and conc. sulfuric acid. The solubility was lower than that of corresponding polyamides from 2,7-triptycenediamine. This lowering was attributed to the more linear and symmetrical structure of the diamine component. The glass transition temperatures (Tgs) of the polyamides were 339—370°C and temperatures at 5% weight loss (Td) were 442—482°C, which indicate that this polyamide has high thermal stability. These thermal properties were as high as those of polyamide from 2,7-triptycenediamine. The aromatic polyimides were synthesized by thermal cyclodehydration from polyamic acids prepared from the diamine with tetracarboxylic dianhydride by ring-opening polyaddition. The inherent viscosities of the polyamic acids were 0.65—0.87 dl g−1. Polyimide from the diamine with 3,3′4,4′-sulfonyldiphenyltetracarboxylic dianhydride was soluble in DMAc, DMF, DMSO, and conc. sulfuric acid. Tgs of polyimides were 391—411°C and Tds were up to 521°C, which were showed high values.