High Thermally Stable and Organosoluble New Poly(amide-imide)s Derived from Bis(4-trimellitimido phenoxy)phenyl Triptycene

Abstract

A triptycene-containing dicarboxylic acid monomer, bis(4-trimellitimido phenoxy)phenyl triptycene, was successfully synthesized by refluxing the diamine, bis(4-aminophenoxy)phenyl triptycene with trimellitic anhydride in glacial acetic anhydride. A series of aromatic poly(amide-imide)s were prepared by condensation polymerization of the dicarboxylic acid monomer and seven different commercially available diamines. The resulting poly(amide-imide)s were soluble in various solvents, such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, and pyridine. The polymers were amorphous and had inherent viscosities in the range 0.40–0.67 dL/g. These polymers had low dielectric constants ranging from 2.09 to 2.18. The glass transition temperatures of these polymers were observed between 229°C and 277°C. These polymers showed good thermal stability without significant weight loss up to 500°C. The temperatures at 10% weight loss ranged from 512°C to 570°C in nitrogen. The UV-Vis absorption spectra revealed that most of the polymers had absorption maxima around 312–348 nm, indicating the conjugation between the aromatic rings and nitrogen atoms. Solvent cast films had tensile strengths from 75 to 108 Mpa, elongates at break of 7%–9% and tensile moduli of 1.7–2.0 Gpa, indicating they were strong materials.

Keywords:

• direct polycondensation
• poly(amide-imide)s
• thermal stability
• triptycene
• UV-Vis absorption