The foam poncho shown below is made of 1/8" thick closed cell foam. It is sandwiched between two layers of mosquito netting. The mosquito netting protects the fragile foam from ripping and makes the poncho slide on and off more easily. I've been testing it as I performed moderate work in the yard during the last week. Weather has been perfect for testing. We've had rain, hail and wind with temperatures in the mid 30s F. This is pretty close to the worst that I experience when hiking during the summer.
I've been experimenting with closed foam clothing because, when backpacking, I am always wet from rain and/or sweat and I get cold as my insulating layers lose their effectiveness. The insulating value of closed cell foam is mostly unaffected by rain and/or sweat.
I've tried 1/2 inch foam in the form of float coats filled with ensolite and I've made test garments out of 3/8" blue foam, 1/4" grey foam and Insultex. This latest experiment (with the 1/8" foam poncho in the photos) is the most successful so far. When considering weight, comfort, drapability and multiple use it comes out the clear winner over the alternatives I have tried.
This 1/8" foam weighs about 3 ounces per square yard. It needs some type of covering on both sides to protect it and to reduce its tendency to cling when wet. So add another couple of ounces per yard. I got it in a 3' wide roll at Home Depot several years ago. I believe it was/is used as underlayment for floors. It is white and shiny and cheap looking. You have probably seen it somewhere in your life as it is quite common.
The poncho in the photo is 3' wide and 6' long. I cut an X in the center for my head. When I put a windbreaker and wind pants over the poncho the foam drapes nicely around my body. It covers my shoulders and the upper half of my arms, all of my torso and continues down to below my crotch in the front and back. It makes me look like I have used too many steroids and am wearing a diaper.
So this 10 ounce rough draft of a poncho looks like a winner for my use. It serves as a reliable insulating garment, raincoat and rainskirt and I can use it as a sleeping pad