Synthesis and Characterization of an Alicyclic Acid Anhydride Containing four Stereoisomers and the Derived Polyamideimides using Diisocyanates

Abstract

AbstractAn alicyclic acid anhydride BOTA, containing four stereoisomers, racemic (1S,2R,3R,4R,5R)‐bicyclo[2.2.2]octane‐2,3,5‐tricarboxylic acid‐2,3‐anhydride (7a+7a’) and racemic (1S,2S,3S,4R,5R)‐bicyclo[2.2.2]octane‐2,3,5‐tricarboxylic acid‐2,3‐anhydride (7b+7b’), was synthesized using phthalic anhydride as the starting material. The chemical structures of the products in each step were fully characterized by NMR spectroscopy, GC‐MS, elemental analysis, and single‐crystal X‐ray diffraction. The polycondensation process involving BOTA and several diisocyanates was applied to prepare PAIs. Furthermore, PAI‐Xs were prepared using methylene diphenyl diisocyanate (MDI) and various mole ratios of BOTA and 4,4'‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA). PAI‐Xs exhibited good solubility in organic solvents such as DMSO, NMP, DMAc, GBL, DMF, and m‐cresol at room temperature. They can form flexible films with low coefficients of thermal expansion (CTE) (51‐70 ppm/°C) and high glass transition temperatures (Tg) (222‐272 °C). They also demonstrated high transparency with transmittance at 500 nm (T500nm) ranging from 77.2‐82.5%. BOTA can be a significant building block in PAI synthesis, offering an alternative to trimellitic anhydride (TMA).This article is protected by copyright. All rights reserved