SHMP改性硫酸钙晶须纸张加填研究

Dissolution Inhibition of Calcium Sulfate Whisker and Its Application as the Filler in Papermaking

关键词:  硫酸钙晶须  溶解抑制  溶解度  留着率

Key Words:calcium sulfate whisker  water resistance  solubility  retention rate

摘要:采用不同改性剂对硫酸钙晶须进行溶解抑制表面处理,通过对改性前后硫酸钙晶须溶解度、表面性质、化学组成和留着率的表征,研究了改性剂对硫酸钙晶须溶解抑制效果以及改性硫酸钙晶须作为造纸填料对纸张力学性能的影响。研究表明,不同改性体系均对硫酸钙晶须溶解性有一定的抑制作用,其中六偏磷酸钠(SHMP)改性效果最好,由EDX和XPS能谱分析可知，改性硫酸钙晶须表面存在钠和磷元素；电导率测试表明，SHMP改性后,明显抑制了硫酸钙晶须的溶解。当反应温度为70℃,SHMP质量浓度为20 mg/L时,改性硫酸钙晶须溶解度低,分散性较好；改性硫酸钙晶须在纸张中加填后,与未改性硫酸钙晶须相比，填料留着率提高了约2.6~3倍。

Abstract:Due to its slight solubility in water, calcium sulfate whisker (CSW) utilized as a the filler in papermaking usually results in its low retention. Different modifiers were used to improve the water resistance of CSW by surface coating. The dissolution inhibition effect of CSW and mechanical properties of the paper filling with CSW were investigated based on the characterization of the solubility, surface properties, and chemical composition of CSW before and after modification. The results indicated that the dissolution of CSW was inhibited with different modifiers, and sodium hexametaphosphate (SHMP) was the most effective chemical in surface modification of CSW according to conductivity test. The existence of Na and P elements in CSW surface was detected from EDS and XPS spectra. CSW with high water resistance was modified at 70℃ using 20 mg/L SHMP. The effects of the modified CSW on the mechanical properties of the handsheets were studied, and the retention of the modified CSW was 2.6~3 times higher than that of unmodified CSW.