I am working on a school project and am trying to make an ice pack that can be put in direct contact with skin without damaging tissue. So I can't use water/ice. I was looking for materials that freeze around 60 degrees F since they won't hurt skin and they would last longer cause the difference in air temperature and pack temperature would be closer. But I am having trouble finding suitable materials. I have been researching for a few weeks now and I am feeling hopeless now. I have found the following:
1)Hexadecane-freezes around 60, but really, really expensive, plus its hazards are questionable.
2)Acetic Acid-also freezes around 60 in the pure state, but way, way to dangerous, didn't even bother finding price or availablity
3)Glycerine-(thought this would be the one) freezes around 60 when it is 99% glycerine 1% water and it is very safe. So I bought some from my local walmart and tried to freeze it. But it won't freeze. I did more research and found out glycerine supercools and is hard to get to freeze.
Does anyone know any other material I can use that is relatively safe and freezes aroun 60F? Or does anyone know how I can get the glycerine to freeze? Or, is there anything I can add to glycerine to stop it from supercooling without lowering its freezing temp?
Any help would be very appreciated since it seems like I have hit a wall.