酸碱两步法改性硅灰石的表征及对纸张性能的影响

研究了经酸碱两步法改性处理后的硅灰石形态结构变化及作为填料对纸张性能的影响。结果表明,先用H2SO4使硅灰石部分溶解,然后调节p H值至碱性,以使溶出物质再沉积到颗粒表面,形成疏松多孔包覆层,在保持硅灰石原有针状形态的基础上,实现了硅灰石颗粒表面结构的重建。与未改性硅灰石相比,改性后硅灰石的粒径有所增加,白度提高;其加填纸的白度高、松厚度好、强度降低少。虽然改性硅灰石在纸张中的留着率低于未改性硅灰石,但高于GCC填料。

Characterization of Wollastonite Modified with Acid & Alkaline Two-step Method and the Influences of Its Application on Paper Properties

In order to improve application effect of wollastonite in papermaking industry, the modification of wollastonite with acid & alkaline two-step method was investigated. The modification process included two steps: firstly sulfuric acid was mixed with wollastonite to result in partly dissolution of wollastonite particles, then pH was adjusted to alkalinity by adding alkaline so as to redeposit dissolved substances on the surface of the wollastonite particles. The loose porous covering layer was formed on the surface of wollastonite particle while original acicular morphology was maintained. The modified wollastonite possessed bigger particle size and higher brightness than the unmodified sample. The paper properties filled with modified wollastonite were superior to those filled with unmodified wollastonite: higher brightness, bulkier, less mechanical strength reduction. Although retention rate of modified wollastonite was a little lower than that of the unmodified wollastonite fillers, but higher than that of GCC filler in paper production.