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本文研究了OCC二次纤维微观结构在不同施胶和干燥条件下的变化情况。研究表明:干燥时间和干燥温度对二次纤维微观结构的影响很大。当干燥温度分别从80℃上升到100℃和从100℃上升到120℃时,纤维中孔的平均孔容分别降低了3.22×10-5cm3/g和5.42×10-5cm3/g;当干燥时间从10 min增加到15 min时,孔径在15~80之间的孔隙的平均孔容下降到4.15×10-5cm3/g。随着干燥时间和干燥温度的增加,纤维中孔隙发生的不可逆关闭现象导致纤维保水值下降,纤维素的结晶度上升。同时,随着烷基烯酮二聚体(AKD)用量的增加,纤维保水值略微下降,而纤维素的结晶度则呈逐渐上升趋势。当AKD的用量达到0.3%时,和未施胶的纤维相比,纤维的保水值下降了11.2%,结晶指数上升了10.0%。然而施胶过程中纤维孔隙的变化很小,表明改变AKD用量对二次纤维孔隙的影响较小。
In this paper, the changes of OCC secondary fiber microstructure under different sizing and drying conditions were studied. The results show that drying time and drying temperature have a great influence on the secondary fiber microstructure. When the drying temperature increased from 80 ℃ to 100 ℃ and from 100 ℃ to 120 ℃, the average pore volume of the mesopores decreased by 3.22 × 10-5cm3 / g and 5.42 × 10-5cm3 / g, respectively. When the drying time From 10 min to 15 min, the average pore volume of pores with pore sizes between 15 and 80 decreased to 4.15 × 10 -5 cm 3 / g. With the increase of drying time and drying temperature, the irreversible closure of the pores in the fiber leads to the decrease of water retention and the increase of the crystallinity of cellulose. Meanwhile, with the increase of the amount of alkyl ketene dimer (AKD), the fiber water retention decreased slightly, while the crystallinity of cellulose showed a gradual upward trend. When the amount of AKD reached 0.3%, the water retention of fibers decreased by 11.2% and the crystallinity index increased by 10.0% compared with unsized fibers. However, the change in fiber porosity during sizing was small, indicating that changing the amount of AKD had less effect on the secondary fiber porosity.