Environment-friendly UV-curable alkyd-based non-isocyanate urethanes
During a new study, two non-isocyanate polyurethanes (NIPUs) were used as reactive diluents for an alkyd to obtain eco-friendly new UV-curable alkyd-polyurethane coatings.
A linseed-based alkyd resin was prepared and formulated with the reactive diluents (NIPUs) and free radical photoinitiator, and then UV-cured. NMRs were used to characterize the alkyd and NIPUs and glass transition temperature (Tg) of cured alkyd-polyurethanes were evaluated by using DSC. Further, spectroscopy and thermal stability of the coatings were evaluated by using ATR-IR spectroscopy and thermogravimetric analysis (TGA), respectively. Moreover, coating properties such as pencil hardness, cross-cut adhesion, pull-off adhesion, impact resistance, and reverse impact resistance were also evaluated.
Significant improvements
It was found that crosslink density, pencil hardness, adhesion, and Tg were dependent and proportional to the amount of the NIPUs (reactive diluents) showing significant improvement in mechanical and thermal properties compared to the linseed-based alkyd resin.
The study has been published in Journal of Coatings Technology and Research, Volume 19, September 2022.
