Curing behavior of UV-curable coating in presence of different multi-functional monomers

The curing behavior of a Urethane-Acrylate UV curable Resin which had been diluted by three monomers (HDDA, TMPTA and DIPEPA), has been studied. Two ClearCoat formulations with different monomer compositions were prepared and cured. Coatings were cut into three thin layers by means of Microtomy sectioning. Both FTIR and HPLC analysis were performed and two critical values including degree of double-bond conversion and amount of residual (remaining unreacted) monomers were calculated. Results show, largest monomer (DIPEPA) doesn’t behave like others. It’s entrapped at the early stage of polymerization and doesn’t gain enough mobility to join to the polymer network in higher irradiation induced temporary free volume.

Keywords: Residual Monomer, ClearCoat, HPLC, Microtomy.