Protect/seal paintless front bumper?

I have a 2007 impreza wagon that I bought used last year. The paint on the front bumper has been steadily peeling away (tried to stop the growth but it looks like a crap paint job was done before it was mine- there are bubbles everywhere). I am thinking of just stripping the paint and leaving the black plastic bumper as is. I live in a city so the life of a pristine bumper is limited already.

What I am wondering if there is any kind of seal or protectant I should put on the plastic? I live at high altitude so the UV is strong and I want to avoid and warping or fading.

thanks!