Comparative Study on the Properties of Epoxy Derived from Aromatic and Heteroaromatic Compounds: The Role of Hydrogen Bonding

Epoxy derived from heteroaromatic compounds and its properties are seldom reported. In this work, two model epoxy monomers (EP-B and EP-F) were synthesized from isophthalic acid and 2,5-furandicarboxylic acid. After curing with 4,4-diaminodiphenylmethane (DDM) in a stoichiometric quantity of 2:1, their properties were comparatively investigated, especially the formation and role of hydrogen bonding in them were identified. Results obtained from differential scanning calorimetry (DSC), dynamic thermomechanical analysis (DMA), fluorescence emission spectra, and static contact angle measurements showed that the cured EP-F/DDM system exhibited unexpected performance in higher glass transition temperature (Tg), fluorescence intensity, and hydrophilicity. And temperature-dependent Fourier transform infrared (FT-IR) analysis further confirmed that it was the more hydrogen bonding in the cured EP-F/DDM, involved with the oxygen heteroatoms in the furan ring, which led to its better properties. This work gives us some new insights into the role of electronegative heteroatoms in epoxy resin synthesized from heteroaromatic compounds.