Synthesis and Properties of Polyimides Derived from 1,4-Bis(4-aminophenoxy)-2-tert-butylbenzene

Abstract

The novel diamine containing bulky tert-butyl substituent, 1,4-bis(4-aminophenoxy)-2-tert-butylbenzene (BATB) was used as monomer with various aromatic tetracarboxylic dianhydrides to synthesize polyimides via a conventional two-stage procedure that included ring-opening polyaddition in a polar solvent such as N,N-dimethylacetamide (DMAc) to give poly(amic acid)s, followed by cyclodehydration to polyimides. BATB(II) was prepared through the nucleophilic displacement of tert-butylhydroquinone with p-chloronitrobenzene in the presence of K2CO3, followed by catalytic reduction. Depending on the dianhydride used, the poly(amic acid)s obtained had inherent viscosities of 0.76–1.79 dL g−1. All poly(amic acid)s could be cast from the DMAc solutions and thermally converted to transparent, fiexible, and tough polyimide films. The polyimide films had high tensile strength of 122–208 MPa, an elongation at breaks of 3–9%, and a tensile modulus of 1.92–2.68 GPa. Polyimides from 4,4′-sulfonyldiphthalic anhydride and 4,4′-hexafluoro-isopropylidenediphathalic anhydride had better solubility than the other polyimides. These polyimides had glass transition temperatures between 240–268°C and 10% mass loss temperatures were recorded at 479–522°C in nitrogen.