A series of water blown polyurethane foams was produced in which polyether polyol content was
progressively reduced by the addition of a designed soybean oil derived polyol (SBOP). A sample from
each foam was tested for a variety of standard properties and a sample from the same foam was also
compression molded into plaques which were tested for elastomer properties. The morphology of the
foams and their underlying elastomers was probed by SEM, AFM, DMA, X-ray, FTIR, tensile properties and
cyclic stress/strain (hysteresis) experiments. The properties of the polyether control and SBOP containing
foams are representative of their underlying polymers. However, foams containing SBOP do not have
well developed hard segment organization relative to that of polyether soft segment control foams.
Similarly, the SBOP foams do not have as good hard segment organization as the elastomers derived by
compression molding the same foams. This suggests that hard segments of SBOP containing foams do not
reach thermodynamic equilibrium prior to vitrification during the foaming process. It is possible that this
is an artifact of the low equivalent weight (ca. 670 gr/eq) of SBOP which promotes gelation ahead of
phase separation. The fact that the elevated temperature modulus is independent of the amount of added
SBOP suggests that tensile properties of the foam are not a function of the soft segment crosslink density,
but rather the hard segment phase separation. Other foam properties such as airflow and tear strength
are shown to be related to the same factors. Improvements in foam properties are achieved by designing
the foam formulation to increase phase separation.