Synthesis and properties of transparent poly(ester‐amide‐imide)s from tert‐butylhydroquinone bis(trimellitate anhydride) and p‐phthaloyl chloride

Abstract Two series of poly(ester‐amide‐imide)s (PEsAIs) with simultaneously bulky side groups, ester and amide bonds were synthesized by copolymerization of tert ‐butylhydroquinone bis(trimellitate anhydride), p ‐phthaloyl chloride and other monomers. These PEsAIs had glass transition temperatures ( T g s) in the range of 231–301 °C, coefficients of thermal expansion (CTEs) of 17–59 ppm K −1 and displayed good mechanical properties with tensile modulus of 2.6–4.5 GPa, tensile strengths of 63–143 MPa and elongations at break of 3.0%–11.7%. All films had good transparency with transmittances at 400 nm ( T 400nm ) of 43%–80%. The introduction of p ‐phthaloyl chloride successfully improved the properties of the polymer with higher transmittance, higher T g and lower CTE. In particular, PEsAI‐b‐60 presented the best comprehensive performance with a moderate T g of 301 °C, low CTE of 17 ppm K −1 and high transmittance ( T 400nm ) of 75%. © 2023 Society of Industrial Chemistry.