"And Mdegenhart is right, the cotton will separate from the polyester over time with repeated washing, resulting in pilling. 100% cotton will fade, fray & thin, but you don't get the horrible pilling like a blend. That said, quilt with what you like. 
Cotton makes me happy, so I quilt with all cotton fabric, thread & batting."[/QUOTE]
Hi, Back in the late 50's and 60's, I think much of the fabrics were polyester/cotton as was thread. I noticed that quilts given me for my wedding came apart at the seams after a few years of use. The thread seemed to 'cut' the seams at the seam line rather than the thread breaking. Has anyone else noticed this? Also my husband's poly/cotton handkerchiefs seem to lose the cotton after many washings and all that's left is the thin polyester (which isn't much good as a handkerchief anymore.) I assume that is what will happen with the polyester/cotton fabric in quilts. And your polyester/cotton sheets get really thin after a lot of use. The cotton gets abraded against the stronger polyester threads and falls out. That's my theory. Am I wrong? Eunice