I have found a cheap source of polyethylene (HDPE as well LDPE) and POLYCARBONATE SHEET. I tried them as an oil painting support and like the feel of oil painted directly on them.

I was wondering how durable this would be? I am mostly looking at 1/8th inch thick material of around 10-12 inches max width or height. I am sure polyethylene (is this same as mylar?) seems impervious to OMS or turpentine but I am unsure if polycarbonate is.. In any case, I do not use any mediums or diluents so I am probably not going to face issues with this.