Synthesis and properties of new polyimides derived from bis[4-(4-aminophenoxy)phenyl]diphenylmethane with various dianhydrides

Abstract

A new kink diamine, bis[4-(4-aminophenoxy)phenyl]diphenylmethane (BAPDM), bearing diphenylmethylene linkage was reacted with various aromatic dianhydrides to prepare the corresponding new polyimides via the poly(amic acid) precursors and thermal or chemical imidization. The poly(amic acid)s were produced with moderate to high inherent viscosities of 0.96–1.68 dl g^–1. All the poly(amic acid)s films could be obtained by solution-cast from N,N-dimethylacetamide (DMAc) solutions and thermally converted into transparent, flexible, and tough polyimide films. The wide-angle X-ray diffraction diagrams revealed that all the polyimides showed amorphous character. These polyimide films had a tensile strength of range 75–147 MPa and tensile modulus of 2.4–3.0 GPa. Polymers PI-3, PI-5 and PI-6 showed excellent solubility in a variety of solvents such as N-methyl-2-pyrrolidinone (NMP), DMAc, N,N-dimethylformamide (DMF), dimethyl sulfoxide, γ-butyrolactone, pyridine, cyclohexanone and tetrahydrofuran. These polyimides had glass transition temperatures between 248–331°C. The thermogravimetric analysis revealed that these polyimides exhibited good thermal stability with polymer decomposition temperature in excess of 500°C in nitrogen and air atmosphere. They had 10% weight loss temperatures in the range of 542–564°C and 549–572°C in nitrogen and air, respectively.