Monday, April 30, 2007

Atomospheric pressure liquefaction of dried distillers grains (DDG) and its application to polyurethane foams

Fei Yu, Roger Ruan, and Paul Chen. Department of Bioproducts and Biosystems Engineering, University of Minnesota, 1390 Eckles Ave, Saint paul, MN 55108

As we know, petroleum resources are naturally limited, and petroleum-based polymers are unfriendly to the environment. The U.S. industry has a goal of achieving 10 percent of all basic chemical building blocks (polymers, enzymes, etc.) from plant-derived renewable sources by the year 2020 which represents at a 5-fold increase in market share from today. Successful research on biomass based products offers potential to improve the durability of these materials, and to reduce the dependence on petroleum resources. This research will demonstrate a reasonable and economical method preparing biodegradable polyurethane foams from crop residues.In this study, two chemical processing steps were illustrated for polyurethane production. First, bio-polyols were obtained from atmospheric pressure liquefaction of DDG in an acidic condition. Ethylene glycol and ethylene carbonate were chosen as liquefaction solvent with the atmospheric pressure liquefaction. DDG was pretreated over a range of conditions, using residence times of 1-3 hours, temperatures of 150-180°C, sulfuric acid concentrations of 1.0-3.0% (w/w), and liquefaction solvent to DDG concentrations of 3:1 – 5:1. Polyurethane foams were then prepared from the liquefied bio-polyols by reacting with diisocyanate. The hydroxyl-rich bio-polyols react with diisocyanate and form cross-linked polyurethane network. The biodegradability of polyurethane foams was also presented. This study strives to broaden the applications of DDG as a feedstock for biopolymer preparation.