| Abstract: | Novel aromatic polyimides were synthesized from 9,10-dihydro-9,10-o-benzenoanthracene-1,5-diamine (2,7-triptycenediamine) and aromatic tetracarboxylic dianhydrides. The polymerization was carried out in a two-step procedure including ring-opening poly-addition giving polyamic acids, followed by thermal cyclodehydration. The polyamic acids have high inherent viscosities (0.97–1.95 dL/g in 1-methyl-2-pyrrolidone). The polyimides show high glass transition temperatures (392–409°C), high decomposition temperatures at 5% weight loss (516–566°C), and high weight residues (64–69% at 800°C). All polyimides are amorphous. The polyimide from the diamine with 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride (4,4′-sulfonyldiphthalic anhydride) is soluble in pyridine, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide and conc. sulfuric acid at 60°C, and shows high thermal stability. The introduction of 2,7-triptycenediyl structure into the polyimide backbone has the effect of improving the solubility and maintaining the high thermal stability. |
