Hi. What about the new fabric made with bamboo. It seems like that would burn quickly. If not, I'd to go with silk, or cashmere. Out of curiosity, why is your teacher encouraging you to light your clothes on fire? I would have never been allowed such a project Very interesting indeed.
Since polyester is a petroleum-based product, it most likely burns faster than any other fabric, unless it has fire/flame retardant additives, which have been pretty much the state of polyester since kids started getting burned up while wearing it.