Liquefaction Of Fermentation Residue From Corn Stover And Preparation Of Polyurethane Foams

The fermentation residue of corn stover was liquefied in polyhydric alcohols asthe liquefying reagent in the present of sulfuric acid as the catalyst at the temperatureof140～180°C. The liquefaction products were used as polyol component for thepreparation of rigid polyurethane foam to replace some parts of conventional (petro-based) polyol components.The liquefaction products and the liquefaction residue were analyzed to investigatethe influences of the feedstock composition and reaction conditions on the liquefactionbehavior and the performances of the liquefaction products.Experimental results indicated that the highest liquefaction yield was64.64%inthe polyethylene-glycolmixture (7︰3, by mass) using sulfuric acid as the catalyst (4%based on the liquefaction reagents by mass) at160°C after2h. The hydroxyl numberand the viscosity of the liquefaction product obtained under such conditions were349mg KOH/g and979mPa·s, respectively. The contents of lignin and ash in theliquefaction residue were16.45%and24.53%, respectively. The liquefaction yield ofbenzene/ethanol extractives from fermentation residue was96.59%under the someliquefaction conditions mentioned above. The liquefaction product, which presented ahydroxyl number of474mg KOH/g and a viscosity of791mPa·s, could also be usedas the polyol component in the preparation of rigid polyurethane foam.The liquefaction products of corn stover fermentation residue were used in thepreparation of rigid polyurethane foam. The performances of the polyurethane foamwere investigated. Experimental results indicated that the increase in the liquefactionproduct content favored the improvement in the strength of the polyurethane foam. Thedensity and the compression strength of polyurethane foam were34.84kg/m~3and137kPa respectively when the liquefaction product replaced40%of petro-based polyol.However, the pores of the polyurethane foam became less regular, andcompression strength was reduced when further increasing the content of theliquefaction product. The TGA data showed that the use of liquefaction product resulted in an increase of initial degradation temperature and a higher carbon residue ofpolyurethane foam. Liquefaction products with various residue contents were used inthe foaming of polyurethane. It was found that a small amount of solid residue in theliquefaction product improved the density and the compression strength ofpolyurethane foam.