Some of the prettiest quilts I've seen are crazy quilts from the Victorian era. I don't believe that the fabrics in them were 100% cotton. They used what was available to them - upholstery fabrics, velvets, satins, sateens, silks, shirtings, etc. any left over remnants from dressmaking. I try not to mix fabrics in one quilt (unless I am making a crazy quilt), but I have made poly/cotton blend quilts and they have stood up quite well. JMHO...
Anita