Not flight related - but subject related, When I was in the RN all of our working uniform and overalls was polycotton, this was 1981 >
Remember the Falklands ? Sir Galahad ? all the crew and Welsh Guards and RE's that came off that ship with horrible burns, and many permanently waterproofed by the polycotton that melted to them.
Not too long after that polycotton gradually was replaced by cotton - especially overalls which became mandatory wear during any emergency situation.
Man made is BAD, Natural fibre is GOOD.