Preparation and properties of polymides, polyamides and poly(amide‐imide)s based on a spirobichroman dietheramine

Abstract

AbstractA novel diamine, 7,7′‐bis(4‐aminophenoxy)‐4,4,4′,4′‐tetramethyl‐2,2′‐spirobichroman (3), was synthesized and used as a monomer with various aromatic tetracarboxylic dianhydrides, dicarboxylic acids and imide ring‐containing dicarboxylic acids, to synthesize polymides, polyamides and poly(amide‐imide)s, respectively. The polyimides 5a–f were prepared from diamine 3 and various aromatic tetracarboxylic dianhydrides via a conventional two‐stage procedure. The intermediate poly(amic acid)s had inherent viscosities of 0,84 – 1,65 dL/g and could be thermally converted into transparent, flexible, and tough polyimide films. Some polyimides were readily soluble in polar solvents such as N,N‐dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidone (NMP). The glass transition temperatures (Tg) of these polyimides were in the range of 155–280°C, and 10% weight loss temperatures were above 450°C in air or nitrogen. Furthermore, a series of polyamides and poly(amide‐imide)s having inherent viscosity between 0,40–1,69 dL/g were prepared by direct polycondensation of the diamine 3 with various aromatic dicarboxylic acids and imide ring‐containing dicarboxylic acids. All the polyamides and poly(amide‐imide)s were soluble in a variety of organic solvents and could be solution‐cast into flexible and tough films. They had Tg values in the 150–237°C range and showed no significant weight loss below 400°C in air and nitrogen atmosphere.