(674d) Polyols and Polyurethane Foams From Crude Glycerol Based Liquefaction of Lignocellulosic Biomass: Effects of Crude Glycerol Impurities On Product Properties

Crude glycerol, a major byproduct from the biodiesel production process, can be used as an effective and cost-effective biomass liquefaction solvent for the production of polyols and PU foams. However, crude glycerol consists of not only glycerol but also some impurities compounds such as soap and methanol and its exact composition varies widely with different biodiesel production processes. To achieve polyol and PU production of consistent and controllable properties, it is vital to evaluate the effects of crude glycerol impurities on the properties of polyols and PU foams. In this study, the chemical compositions of five crude glycerol samples from different biodiesel plants were first determined, and then the effects of crude glycerol impurities on polyol and PU properties were studied. Our results showed that the composition of different crude glycerol samples varied widely from each other, but all samples were shown to contain glycerol, soap, methanol, fatty acid methyl esters (FAMEs), water, glycerides, free fatty acids (FFAs), and ash as their main components. To investigate the effects of crude glycerol impurities on polyol and PU properties, crude glycerol impurities were mixed with pure glycerol at different formulations and then the mixtures were used as biomass liquefaction solvents for polyol and PU production. Our results showed that the properties of polyols and PU foams were significantly affected by soap, FFAs, and FAMEs: the hydroxyl number of polyols and the density and compressive strength of PU foams decreased significantly with increasing levels of these compounds in liquefaction solvents.  Other crude glycerol impurities such as methanol and water were shown to have insignificant effects on the properties of polyols and PU foams.