COMPARATIVE STUDY OF CORN STOVER HEMICELLULOSE EXTRACTION METHODS AND EFFECTS ON SUBSEQUENT PULPING

Potassium hydroxide (KOH) and sodium hydroxide (NaOH) were used for the extraction of corn stover hemicellulose. the composition of the hemicellulose polysaccharides in the extract and their corresponding contents were detected by ion chromatography. After extraction, the residues were experienced NaOH-AQ pulping. Results indicated that alkaline extraction had significant effect on the dissolution of corn stover hemicellulose, when extraction temperature was 75 degrees C, extraction time was 2h, extraction liquor was 1.5mol/L KOH, and the extraction yield of hemicellulose reached 99%. 55 degrees C hot water treatment had little effect on hemicellulose dissolving. When extraction temperature was 75 degrees C and extraction time was 2h, yield of hemicellulose from KOH was 20.5% higher than that from NaOH at the same OH(-) concentration. Results of pulping showed that after alkaline extraction, Kappa number decreased and brightness was much higher than the one without extraction, the yield of NaOH-AQ pulp was almost the same when different extraction methods were used, about 10% lower than that of the pulp from material without extraction. Tear index of the pulp from the extracted material increased greatly, while other physical properties such as density, breaking length and burst index decreased.