Styrofoam has not a fixed melt and boiling point, like the basis material Polystyrol.
Styrofoam is a kind of foam, which density is dependent on the production. At this stuff is the density the nominal density. The other physics properties are dependent on the nominal density. You can see that at picture 2.1.-3., if the nominal density raises then the compressive stress, the tensile force and the bending strength rise.
After producing, you can work with the Styrofoam at once, but this is not loadable for 100%. Then direct after the stuff is draw from the machine the loadable behave only 70%. After 24 hours the foam is loadable for 90% and four month later the Styrofoam can using complete. That the loadable increase so fast is explain, that the air pressure in the cells is level out.
The stuff has low heat conductivity. This dependent on the nominal density, temperature and moisture contend in the foam. The load of foam and the nominal density are dependent the heat capacity. Styrofoam resist for a short time temperatures load till 100°C. The terminal expansion coefficient is 0.00007 1/K.
Styrofoam is not hygroscopic but it can absorb moisture. Especially if the steam concentration is different at two sides then the steam diffuses though the foam. This behaviour is intensifying if a temperature difference is available. This behaviour expresses though the diffusion - resistance- number. This number is dependent on the nominal density.
Styrofoam is an electrical non conductor. This material is resistant against animal and vegetable fat as soon as paraffin containing corrosion prophylactic. It is not unhealthy, that mean any toxic vapour or toxic chemicals are escape even after a very along store.
Styrofoam is a very elastic stuff, which has a smooth surface. These properties make them to the ideal packing stuff. The thermal conduct and the heat conductivity give them the property of isolation. This is use in the industry of packing and of building. So you can pack foot and drinks for a good while and this thinks can be cool or hot and buildings are isolated.
Because that's a very simple machinability with the different methods and you can make different forms, this stuff is use in the promotion industry.
Picture II.13: properties of Styrofoam arts for the packing industry