Stoichiometric analysis of hydrogen bonding interactions in a mixture of cross-linking resin monomers
Seungwan Ryu, Xiaohui Liu, Ying Jin, Jirun Sun, Young J. Lee
We investigate multiple hydrogen bonding interactions in a binary mixture of cross-linking resin monomers: urethane dimethacrylate (UDMA) and triethylene glycol-divinylbenzyl ether (TEG-DVBE). We analyze infrared (IR) absorption spectra observed at various mixture compositions to determine the relative equilibrium constants among key hydrogen bonding formations. The amount of free and hydrogen-bonded carbonyl groups determined by semi-analytical peak fitting is consistent with a simplified stoichiometric model containing two UDMA acceptor groups (carbonyl and alkoxy oxygens) and one TEG-DVBE acceptor group (ether oxygen). The stoichiometric model is further supported by the peak fitting of the hydrogen-bonded amine stretching band. These results suggest that inter-association between UDMA and TEG-DVBE is non-negligible compared to UDMA self-association. Quantitative information on monomer interactions can provide insight into the copolymerization reaction mechanism of this resin mixture.