We have a special enzyme in our bodies that catalyzes that reaction and allows it to occur orders of magnitude faster. Richi explained the structure of the polystyrene is not changed. The acetone simply removes a substance that allows the 'puffiness' of the foam. Most of the volume is occupied by air. This trapped air makes a very good insulator, which is one of the largest uses for the material.
Nothing is a better insulator than anything.
If a complete vacuum surrounds a material, there are no atoms or molecules to transport the heat from the hot side to the cold side. After some time, the tube became as cold as the liquid nitrogen and the hissing stopped. When the rubber tube was removed, it was frozen as hard as steel. At this temperature, rubber has very different properties than the rubber commonly known. Struck with a hammer this frozen rubber tube with shatter like glass.