改性水凝胶包覆石膏晶须及在造纸过程中的溶出抑制

Modification of Gypsum Whisker by Hydrogel and Its Inhibition of Calcium Sulfate Dissolution in Papermaking Process

关键词:  石膏晶须  水凝胶  包覆  溶解度  留着率

Key Words:gypsum whiskers  hydrogel  modification  solubility  retention rate

摘要:针对石膏晶须用作造纸填料时出现溶解度高、留着率低等问题,本研究采用改性水凝胶（CMC-Al2(SO4)3）对石膏晶须进行包覆处理,分析包覆处理对石膏晶须的钙离子溶出的抑制作用；通过抄纸实验，分析使用改性石膏晶须在白水中的钙离子含量、石膏晶须留着率以及对成纸物理性能的影响。结果表明，用改性水凝胶包覆石膏晶须能有效地抑制硫酸钙溶解,溶解度较未包覆石膏晶须的降低59.2%；显微镜观察发现包覆石膏晶须表面有高分子物质。将包覆石膏晶须用于抄纸时,白水中钙离子的浓度较未包覆石膏晶须降低40.0%~41.6%；包覆石膏晶须的单程留着率达到56.7%～60.7%；纸张强度随包覆石膏晶须用量的提高而下降,纸张白度上升；较适宜的包覆石膏晶须用量为20%。

Abstract:A hydrogel of CMC-Al₂(SO₄)₃ was used to encapsulate the gypsum whiskers in order to solve the trouble such as high solubility, low retention rate when used as filler in papermaking process. The effect of hydrogel treatment of the gypsum whisker on the dissolution inhibition of calcium ion was also investigated. The changes of calcium ion content in the white water and the retention of gypsum whisker as well as the physical properties of the paper were also studied by papermaking experiments. The results showed that the coating CMC-Al₂(SO₄)₃ hydrogel on gypsum whisker was effective in inhibition of the dissolution of calcium ion. The solubility of the treated gypsum whisker was decreased by 59.2% compared with that of unmodified. Microscope observation indicated that the surface of the modified gypsum whisker was coated with a polymer. When it was applied in papermaking, the concentration of Ca²⁺ in the white water decreased by 40.0%～41.6% as compared with that of unmodified while the its retention rate reached 56.7%~60.7%. The physical strength decreased with the increase of dosage of modified gypsum whisker. However, the whiteness of the paper was enhanced with the increase of dosage．