PVC isn't particularly great for holding screws depending on its thickness. It works well to "cap" another material like wood which is a better substrate for holding screws. Screws through PVC into another substrate work well.
I don't know the particulars of your application. When I use PVC I secure it with an adhesive compatible with the PVC and the substrate I'm securing it too.
Not all PVC is resistant to UV light
. If your application will be exposed to sunlight make sure you use the PVC that is.
Good luck with your project!