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Structure and Thermal Properties of Polyurethane Foams Prepared From Liquefied Corn Stover with PAPI

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  2007 ASAE Annual Meeting  076133.(doi:10.13031/2013.22953)
Authors:   Tipeng Wang, Zhihuai Mao
Keywords:   Liquefaction, polyurethanes, thermal properties, corn stover, PAPI

Corn stover (CS) was liquefied by using ethylene carbonate (EC) as liquefying solvent and sulfur acid as catalyst at 170°C for 90 min. Polyurethane (PU) foams were prepared by one-shot method through co-polymerization of untreated liquefied corn srover (LCS) with polymethylene polyphenylisocyanate (PAPI) in the presence of blowing agent, co-catalyst and surfactant. The effects of [NCO]/[OH] ratio, ranging from 0.4 to 1.0, on the structure and thermal properties were studied by means of Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). FT-IR analysis indicated the formation of urethane linkages and the occurrence of secondary reactions in co-polymerization. Decomposition of all samples mainly occurred in four successive stages, and with an increase of [NCO]/[OH] ratio, the glass transition temperature (Tg) and the initial decomposition temperature increased and the range of Tg expended, which can be attributed to the increase of crosslink density in LCS-PU foams.

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