Synthesis and characterization of new cardo polyamides and polyimides containing tert-butylcyclohexylidene units

Abstract

A new cardo diamine monomer, 1,1-bis[4-(4-aminophenoxy)phenyl]-4-tert-butylcyclohexane containing tert-butylcyclohexylidene units was prepared in three steps from 4-tert-butylcyclohexanone. The monomer was reacted with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to produce polyamides and polyimides, respectively. All the polymers, characterized by X-ray diffraction, are amorphous. These cardo polymers exhibit good solubility in a variety of solvents. Almost all polymers are soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), pyridine, and even in tetrahydrofuran (THF) and cyclohexanone. The polymers show glass transition temperatures between 244–310°C and decomposition temperatures at 10% mass loss ranging from 486–526°C in nitrogen. The tough and flexible polymer films have tensile strength of 77–137 MPa, elongations at break of 5–14%, and tensile moduli of 2.0–2.6 GPa.