So I started going through my hunting clothes last night and I am completely confused and thee different types of materials. What I've found is the following:

1. Heavy-weight long underwear - The tag says they are made of 100% polyolefin.







2. Light-weight long underwear - The tag says they are made of 100% polypropylene.







3. Middle-weight long underwear - The tag says they are made of 96% polyester.







4. Heavy-weight long underwear. - The tag says they are made of 70% polyester and 30% wool.





5. Camo pants - Tag says they are made of 100% polyester and have Windstopper in them (they would be used as a middle layer).







6. Flannel shirt - 100% cotten - (it would be used as a middle layer)


Can someone please explain the difference between polyolefin, polypropylene, and polyester? If a piece of clothing is made from polyester, but is not fleece, is it still a good insulator? Why is cotton clothing bad as a middle layer? Which of the pieces of clothing listed above should I use this season and which should be replaced?