Study on structure and pyrolysis behavior of lignin derived from corncob acid hydrolysis residue

The structure and pyrolysis charateristics of lignin isolated from corncob acid hydrolysis residue (CAHL) were studied. Characteritic bands corresponding to guaiacyl and syringyl groups were detected by FTIR, and CAHL particle was polygonal in shape with multiple conchoidal fracture surface. Result of TGA showed that CAHL underwent thermo-degradation at a wide temperature range of 180-850 degrees C, and two mass loss peaks were observed at 237 degrees C and 340 degrees C. Evolution of methanol and phenols were mainly detected at 150-420 degrees C, while CO2, CO and CH4 appeared to be the main gaseous products at temperature above 400 degrees C. Py-GC/MS analysis showed that phenolic compounds, mainly consisting of guaiacol- and syringol-type, were generated from cracking of arylglycerol-beta-ether (beta-O-4) linkage in CAHL. SEM analysis showed that portoins of CAHL char appeared brittle with conchoidal fractures at 550-750 degrees C, and vesicle was observed due to plastic formation above 850 degrees C. (C) 2011 Elsevier B.V. All rights reserved.