The miscibility and intermolecular-specific interactions in thermosetting blends of epoxy resin (ER) with poly(ethylene oxide) (PEO) cured with various amounts of 1,3,5-tridroxybenzene (THB) were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The glass-transition behavior indicated that all the blends were miscible and had homogeneous amorphous phases; FTIR showed that there were the intermolecular hydrogen-bonding interactions between crosslinked ER and PEO. However, both the glass-transition behavior and infrared spectroscopy also indicated that the intermolecular interactions were significantly reduced by the formation of crosslinked structures, which was shown by comparing the experimental results of poly(hydroxyether of bisphenol A) (PH)/PEO and ER/PEO blends cured with various amounts of the curing agent. In ER/PEO blends the intermolecular hydrogen-bonding interactions were much weaker than the self-association of hydroxyls of ER, which was in marked contrast to the interactions in PH/PEO blends. In ER/PEO blends with various amounts of the curing agent, the intermolecular interactions between epoxy polymers and PEO were reduced with an increasing degree of crosslinking. The results were interpreted in terms of the effect of crosslinking on the intermolecular interactions, such as steric shielding, the screening effect, and chain connectivity resulting from the formation of the three-dimensional crosslinked network, which could reduce the intermolecular hydrogen-bonding interactions among hydroxyls of ER versus ether oxygen atoms of PEO. (C) 2004 Wiley Periodicals, Inc.