Synthesis and Characterization of New Cardo Polyamides and Polyimides bearing a 4-Phenylcyclohexylidene Unit

A new cardo diamine monomer, 1,1-bis[4-(4-aminophenoxy)phenyl]-4-phenylcyclohexane bearing a 4-phenylcyclohexylidene unit, was prepared in three steps from 4-phenylcyclohexanone. The monomer was reacted with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to produce novel polyamides and polyimides, respectively. The polyamides were prepared utilizing Yamazaki reaction conditions with inherent viscosities of 0.62–0.98 dL·g–1. The polyimides were prepared by a two-stage procedure that included a ring-opening polyaddition to give poly(amic acid)s, followed by thermal or chemical cyclodehydration. By chemical cyclodehydration, the obtained polyimides had inherent viscosities of 0.61–0.93 dL·g–1. Most of the polymers dissolved in N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, pyridine, and cyclohexanone. These polymers showed glass transition temperatures between 225–312°C and decomposition temperatures at 10% weight loss temperatures ranging from 470–500°C and 480–510°C in nitrogen and air atmosphere, respectively. These tough and flexible polymer films had a tensile strength of 81–124 MPa, an elongation at break of 8–21%, and tensile modulus of 2.0–2.8 GPa.