Is it possible to treat a stretchered canvas with polyurethane, epoxy resin or some such, to make it waterproof enough to hang over the bathroom shower?

The canvas is unframed, about 20” x 40”, and would just hang on a wire attached to back. Sort of like restaurant tables with artwork and other things imbedded under a protective surface. The painting is really only of value to me, but I wouldn’t mind if it lasted a long, long time.