Info

Miscellaneous foams

foam

foams of all types

foams

foams

aTable based on data reported in Table ES-1 and Table 1 in 1998 Report of the Flexible and Rigid Foams Technical Options Committee, United Nations Environmental Program, Nairobi, Kenya, December 1998. ^Conductivity expressed in (mW/m K at 10°C).

aTable based on data reported in Table ES-1 and Table 1 in 1998 Report of the Flexible and Rigid Foams Technical Options Committee, United Nations Environmental Program, Nairobi, Kenya, December 1998. ^Conductivity expressed in (mW/m K at 10°C).

beads are made by polymerization of styrene in the presence of pentane (or by incorporation of pentane into preformed beads under pressure). The fraction of about 6% pentane trapped in the bead is the sole blowing agent. These might be steam expanded and molded into products or sheets. The pentane is a VOC and is also flammable (so is polystyrene), limiting the application of these foams in certain situations.

In extruded boardstock manufacture the polystyrene beads and foaming agents are fed into an extruder where the beads expand, incorporate the blowing agent, and are passed through a die. Freon (HCFC-142b and HCFC 22) is used as the primary blowing agent popularly in polystyrene foam boardstock in most parts of the world. While these are low ozone depleting, they also obtain excellent thermal insulation characteristics. Zero ozone-depleting polymer (ODP) alternatives are, however, available for polystyrene foam boardstock manufacture and include HFCs (HFC 134, HFC 134a, and HFC 152a), blends of HFCs and carbon dioxide, and carbon dioxide.

Was this article helpful?

0 0
Building Your Own Greenhouse

Building Your Own Greenhouse

You Might Just End Up Spending More Time In Planning Your Greenhouse Than Your Home Don’t Blame Us If Your Wife Gets Mad. Don't Be A Conventional Greenhouse Dreamer! Come Out Of The Mould, Build Your Own And Let Your Greenhouse Give A Better Yield Than Any Other In Town! Discover How You Can Start Your Own Greenhouse With Healthier Plants… Anytime Of The Year!

Get My Free Ebook


Post a comment