Polyurethane (PU) rigid foams were synthesized by substituting a polypropylene-based polyol with
soybean oil-based polyol (SBOP). All the soy-based foams maintained a regular cell structure and had
even smaller average cell size than the control foams. The density of soy-based foams was within 5% of
the controls, except that the density of foams from 100% SBOP was 17% higher. Soy-based foams also had
comparable initial thermal conductivity (k value) and closed cell content, higher Tg and compressive
strength. However, while foams from 50% SBOP showed similar increase in k value to the 0% SBOP foams,
under accelerated aging conditions, the 100% SBOP foams aged faster. Gas permeation tests performed on
PU thin films showed higher N2 permeation for PU thin films made from SBOP which is believed to be the
cause of accelerated thermal aging.