• Why use foam? • PUF for geo-technical applications
Polyurethane foam (PUF) is a two-part chemical system that changes from a liquid to a solid as it expands. PUF is typically a binary, self-contained system, meaning you only have to combine the two parts to make it work, no water is required and it does not react with air.
PUF requires some type of additive to make a gas which causes expansion. There are three broad types of expansion or “blowing" agent, solvent, water or a combination of those two, referred to as “co-blown.” The blowing agent, even if it is water, is already included in the chemicals.
PUF gets stronger and more stable as the density increases. Densities range from less than one pound per cubic foot (pcf) to more than 10 pcf. In general all PUF chemicals weigh around ten pounds per gallon. The final density is a function of the expansion ratio.
PUF is generally inert, especially at higher densities. PUF is generally NOT fire retardant, although it can be made more fire resistant with some additives. PUF will not break down or leach in the ground or in contact with water. PUF will absorb water based on its density and percent of open cells.
Things to look for in PUF are: type of blowing agent, free rise density, closed cell content, compressive strength, gel and rise time and dimensional stability.
-Joel Tigner, Batworks, LLC (full)
4255 S. Eagleson Rd
Boise, ID 83705
Phone: 800.556.9641
Fax: 877.327.1196