What materials are life rafts made of?

I was surprised to see that nobody had posted an answer for this question, and even though I found it looking for the answer myself, I still do know that inflatable rafts such as the ones used for white water rafting, life boats, police boats, etc. are made of a special kind of rumber that is thick, durable, and flexable enough for its many boat related jobs. However, that is all I know, as I mentioned earlier(I just though that this info would be better than nothing). So if you can get more spacific than that, please enter your own answer on to this site and help fill in the gaps that I just don't know how to give answers for. P.S. To whoever finds the answers, CONGRATZ , you helped finish somthing I tried to do and couldn't at the time. GOOD LUCK