Molecular Design of High‐Performance Polyarylates: Comparative Effects of Incorporating Phenolphthalein and Hexafluorobisphenol A

Polyarylates (PAR) are high‐performance engineering plastics of significant research interest due to their mechanical properties, processability, and gas barrier performance. In this study, phenolphthalein and hexafluorobisphenol A (BPAF) monomers are introduced at different concentrations into the main chain of PAR. The mechanisms by which rigid benzene rings and polar fluorine‐containing groups modulate material properties are systematically investigated and compared. The incorporation of both monomers effectively enhances the thermal stability and hydrogen barrier properties of the materials. When 30 mol% phenolphthalein is incorporated, the material exhibits a minimum complex viscosity of 9.1 × 10 2 Pa·s (305°C), and the hydrogen permeability coefficient is 9.13 × 10 −11 cm 3 ·cm·(cm 2 ·s·cmHg) −1 . The incorporation of BPAF significantly enhances the mechanical properties of the material, with an elongation at break of over 23.59% ± 2.48%. When 30 mol% BPAF is incorporated, the material shows a minimum complex viscosity of 1.2 × 10 2 Pa·s (294.5°C), and a hydrogen permeation coefficient of 9.32 × 10 −11 cm 3 ·cm·(cm 2 ·s·cmHg) −1 . Both modifications result in polymers with excellent melt processability, with the BPAF‐modified system exhibiting lower viscosity for easier processing and molding. This work elucidates the mechanisms through which phenolphthalein and BPAF monomers modulate the comprehensive properties of PAR, thus enriching the modification strategies for the development of high‐performance PAR materials.