Colorless poly(ester imide)s derived from hydrogenated trimellitic anhydride

Tetracarboxylic dianhydrides were synthesized from hydrogenated trimellitic anhydride (HTA) and some diols to obtain novel poly(ester imide)s (PEsIs). The HTA-derived tetracarboxylic dianhydrides showed much higher reactivity with various diamines than conventional cycloaliphatic tetracarboxylic dianhydrides and led to PEsI precursors with high molecular weights (Mw). The results can be explained in terms of a spacer effect. The PEsI films were essentially colorless regardless of diol and diamine components owing to inhibited charge-transfer interactions. The HTA-derived PEsIs also exhibited excellent combined properties: relatively high glass transition temperatures (Tg), relatively low water absorption (WA), and relatively low dielectric constants. The outstanding processability (thermoplasticity and solubility) observed for the HTA-derived PEsIs was discussed on the basis of a non-planar/bent structure at the HTA-based imide units. The use of a fluorene-containing diol component was effective for enhancing Tg’s by restricted internal rotation and for reducing WA by a decreased imide group content. On the other hand, the use of 4,4′-biphenol as another diol gave rise to a prominent toughening effect without sacrificing other target properties. One of the HTA-derived PEsI systems can be a promising candidate as plastic substrates because of its excellent combined properties: a high Tg close to 300 °C, high optical transparency, significant toughness (elongation at break > 100%), and good thermo- and solution-processability.

Graphical abstractNovel colorless poly(ester imide)s (PEsIs) were obtained from diamines and tetracarboxylic dianhydrides which were synthesized from hydrogenated trimellitic anhydride (HTA) and various diols. One of the HTA-derived PEsIs developed in this work displayed excellent combined properties: a high Tg close to 300 °C, high light transparency at 400 nm, significant toughness (elongation at break > 100%), and good thermo- and solution-processability.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► This work proposes new materials applicable as plastic substrates in display devices. ► We designed and synthesized novel monomers from hydrogenated trimellitic anhydrides. ► The tetracarboxylic dianhydride monomers showed excellent reactivity with diamines. ► They led to novel colorless poly(ester imide)s with excellent combined properties. ► High Tg (∼300 °C), significant toughness, and good thermo-/solution-processability.