I found a discarded military tent made in plastic (1 mm thick). I recently cut out some of it and tested sewing in it. It worked quite well but precisely as with leather it ‘sucks’ on to the presser foot. This can to my knowledge be solved in two ways: * install a walking foot (this is unfortunately not available for my machine) * glue a piece of special plastic to the underside of the presser foot to decrease the friction.
Unfortunately I discovered that the plastic smells a lot. This is probably caused by (toxic) softeners added to the plastic during manufacturing. This has caused me to discard the material and focus on nontoxic materials instead.