Barrier coats versus inert atmospheres. The elimination of oxygen inhibition in free-radical polymerizations

The polymerization of UV-curable coatings that react by a free-radical mechanism is subject to oxygen inhibition which can be avoided by utilizing an inert atmosphere. We demonstrate that wax barrier coats used to prevent evaporation of volatile reactive monomers are equally effective in preventing oxygen inhibition. No quantitative difference is found between the degree and rate of polymerization in an inert atmosphere or with a wax barrier coating. However, when used above a given ceiling temperature, the wax barrier allows oxygen diffusion which inhibits cure.