Oh, and if I were making quilted pot holders, I would use one or two layers of 100% cotton low-loft. I would never use anything with polyester or mylar in it. (insulbrite)
Polymer materials give off toxic gases when they catch fire.
An all-cotton potholder will catch fire and burn, but the material isn't going to melt and smoke and off-gas stuff to irritate your eyes and throat and lungs. :)