Abstract: Bamboo dissolving pulp was prepared by alkaline extraction method with bleached bamboo pulp as raw material. The cellulose crystalline structure and the fiber surface morphology from the samples treated before and after the extraction were observed by X-ray diffraction and field emission scanning electron microscope (FE-SEM). The changes of molecular weight distribution (MWD) of carbohydrate were studied by the technology of gel permeation chromatography (GPC). The bamboo dissolving pulp was obtained by hydrochloric acid treatment after alkaline extraction. The results showed that the removal rate of hemicellulose was up to 66.71% after treated by 10% of pulp concentration and 10% of sodium hydroxide concentration at 30℃ for 60 min. The FE-SEM results showed that the phenomenon of surface-fibrillated fiber resuced, the fiber lateral width widened and the softness of fiber increased with the removal of hemicellulose. The GPC showed that the polydispersity with the removal of hemicellulose reduced, decreased polydispersity index(PDI) from 7.71 to 4.43, molecular weight of cellulose samples increased. Thus, the uniformity of the molecular weight distribution was improved. And the pulp after optimal alkaline extraction was subjected to subsequent acid treatment which led to 7.02% of hemicellulose, the α-cellulose of bamboo dissolving pulp was 94.25%.

Key words: bleached bamboo pulp, alkaline extraction, crystalline structure, molecular weight