Synthesis and properties of aromatic polyimides derived from 2,7‐triptycenediamine

Abstract

AbstractNovel 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.