Syntheses of Colorless and Transparent Poly(ester imide)s and Their PET Blends: Thermo-Mechanical Properties and Optical Transparency

Abstract

1,2,4-Benzenetricarboxylic acid-1,4-anhydride butylene ester (BCAB) was synthesized from trimellitic anhydride chloride and 1,4-butanediol. The synthesized BCAB was reacted with six different diamines to produce poly(amic acid)s (PAAs), which were cyclized to yield polyimides (PIs) containing ester linkages using the thermal imidization method. Various poly(ester imide)s (PEsIs) were synthesized from structurally different aromatic diamines. The PEsI containing 2,2'-bis(trifluoromethyl) benzidine (TFB) was blended with various concentrations of poly(ethylene terephthalate) (PET) using the solution blending method. To investigate the properties of the blends, they were processed into films using a hot press. In the PEsI/PET blends, PET was not compatible with the PEsI at the tested concentrations. The addition of PET improved the optical transparency of the PEsI hybrid films, but resulted in the deterioration of their thermomechanical properties.