Aromatic poly(ester imide)s and poly(amide imide)s having 1,1′-binaphthyl-2,2′-diyls in the main chain

Abstract

Two new 1,1′-binaphthyl-2,2′-diyl-based dianhydrides, i. e., 2,2′-bis(3,4-dicarboxybenzamido)-1,1′-binaphthyl dianhydride (BNDADA) and 2,2′-bis(3,4-dicarboxybenzoyloxy)-1,1′-binaphthyl dianhydride (BNDEDA), were synthesized and polymerized with various aromatic diamines to afford polyimides through the traditional two-step method. The polyimides with inherent viscosities ranging from 0.27 to 0.70 dl·g–1 showed excellent solubilities in polar solvents such as DMAc, DMSO and NMP etc., except of the poly(ester imide) prepared from BNDEDA and benzidine. Poly(ester imide)s based on BNDEDA can also be readily dissolved in weakly polar solvents such as THF, CH2Cl2 and CHCl3. The glass transition temperatures of these polyimides are in the range of 210–310°C; the 5% weight loss temperatures are in the range of 390–465°C in nitrogen and 384–447°C in air. These polymers form light yellow, tough films that were transparent above 365 nm. The effects of different flexible units attached in the 2- and 2′-positions, i. e., amide, ester and ether, on the properties of the polyimides obtained are discussed.