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.
Bibliographical noteFunding Information:
The authors would like to acknowledge Cargill Incorporated and IREE (Initiative for Renewable Energy and the Environment) for financial support. Throughout this work, we had many helpful discussions with Professor Tom Hoye, Professor Marc Hillmyer, Dr. Junghwan Shin and Dr. Harikrishnan G. of the University of Minnesota. We would also like to thank Darius Jaya and Jason Zhang of the University of Minnesota for their help with sample preparation, Professor Michael Tsapatsis for use of the permeability cell and Matthew Caldwell, Cargill Inc. for his assistance with closed cell content measurements.
- Polyurethane foam
- Soybean oil-based polyol
- Thermal conductivity