A rapid, eco- and environmental friendly alternative to oil oxidation for the preparation of fatty coatings using photoinitiated thiol-ene chemistry

In the quest for green and friendly processes in polymer chemistry, we report herein a new process for bio-based coatings as an attractive alternative to the common drying of oils. This process involves the photoinitiated thiol-ene chemistry under air for the preparation of linseed oil-based biocoatings. Several parameters were investigated to determine the optimal formulation composition and irradiation conditions. Native or stand linseed oil triglycerides were then crosslinked in the presence of 0.5 equivalent of various thiols (SH/ene) under 20 min UV exposure, without photoinitiator nor solvent. 10-20 μm thick coatings constituted of about 80 wt% of linseed oil were obtained. They exhibited at least equal physico-chemical properties compared to coatings dried by simple oxidation. It was found that oxidation of fatty moieties occurred during and after irradiation and has a beneficial effect on the properties of the final coatings.