Karen made a very good point about using polyester in a quilt. This should be enough to deter anyone from using polyester, even as a batting.

Not only is the melting factor something to consider but the quality of the quilting may not be as nice, perfect or uniform. Poly is a much stronger fibre than cotton and it may also have a tighter weave. This would make it difficult for tension and cause you to break alot of thread. Many longarmers I know wont accept poly or polycotton fabrics for backing.

Many years ago when I tried machine quilting on my sewing machine and using a John Flynn frame I was using polycotton fabric and had a heck of a time with. I thought it was my machine or even me but the entire time, the culprit was the polycotton.

Im sure you can find some use for it but if it's all you have then go ahead but keep in mind what was said.