You can make a quilt out of whatever you like - cotton is the favorite because it's easy to work with and affordable.
Other fabrics can be more difficult to work with and create a nightmare for a new sewer...but thirty years ago people regularly used polyester in their quilts and people still today often use satin and velvet in crazy quilts. There are no rules.
I don't know about Rayon being more flammable than any other non-flame retardent fabric, but if that's true then I would take that into consideration. Other than that, do what pleases you.