竹浆粕加工中的漂白工艺

Bleaching process of bamboo pulps processing

利用竹子制备适用于生产醋酸纤维和Lyocell纤维的浆粕,研究加工过程中的漂白工艺。结果显示:酶质量分数为0.04%时,木聚糖酶预处理的效果达到最佳;DMD能够有选择地氧化木质素,提高H2O2的漂白能力,当丙酮与过硫酸氢钾质量比为3∶4时,DMD具有最佳的脱木质素和辅助漂白效果。在这2种预处理阶段,卡伯值的降低量占整个漂白过程降低量的37.9%,特性黏度的降低量仅占整个漂白过程降低量的13.7%。X射线衍射分析间接证明了DMD的脱木素作用,在漂白过程中,DMD处理会降低竹浆粕的结晶度和晶粒尺寸,但其他阶段竹浆粕的结晶度和晶粒尺寸是增加的。

A dissolving pulp suited for production of acetate and Lyocell fibers was prepared with bamboo, and the bleaching process was studied. The results showed that the optimal effect can be obtained when the dosage of xylanase is 0.04% in the enzymatic pretreatment. Dimethyloxirane （DMD） can oxidize lignin selectively and enhance H2O2 bleaching. The optimal delignifieation and assistant bleaching effect of DMD are found when the mass ratio of acetone and hydrogen potassium persulfate is 3：4. In these two pretreatment stages, the decrease of Kappa number accounted for 37.9 % of the total decrease in the entire bleaching process, while the decrease of intrinsic viscosity only made up 13.7%. X-ray diffraction proved the delignification of DMD for bamboo pulp. DMD treatment resulted in the decrease of erystallinity and erystallite size of bamboo pulp during bleaching. However, its crystallinity and crystallite size increased in other stages of bleaching.