碳酸钙超细研磨用分散剂的制备与应用

Synthesis and Application of Dispersant for Ultrafine Ground Calcium Carbonate Grinding

关键词:  超细研磨  重质碳酸钙  回黏黏度  粒径  分散剂

Key Words:ultrafine grinding  ground calcium carbonate  stick back viscosity  particle size  dispersant

摘要:采用水溶液自由基聚合的方法，以丙烯酸（AA）和2-丙烯酰胺-2-甲基丙磺酸（AMPS）为聚合单体，过硫酸铵为引发剂，次亚磷酸钠为链转移剂，制备研磨碳酸钙（GCC）超细研磨用分散剂二元聚合物P（AA-AMPS）。考察了单体配比、引发剂用量、链转移剂用量、反应时间、反应温度等对P（AA-AMPS）的性能及GCC助磨效果的影响，并用红外光谱（FT-IR）、核磁共振碳谱（13C-NMR）、液相凝胶渗透色谱（GPC）及热重分析（TG-DTG）对P（AA-AMPS）的结构及分子质量进行表征。通过单因素实验优化得出，单体配比m（AMPS）∶m（AA）=0.25，引发剂用量4%（占单体总质量分数），链转移剂用量7%（占单体总质量分数），反应时间5.5 h，反应温度80℃时，聚合物的各项性能最佳。将合成的分散剂用于GCC的超细研磨，通过探讨分散剂用量及添加方式对研磨效果的影响，确定了最佳的研磨条件。与商品助磨剂比较，相同研磨条件下，P（AA-AMPS）研磨GCC浆液<2 μm的含量为97.2%，P（AA-AMPS）对GCC的助磨效果更明显。

Abstract:Using the technology of free radical polymerization, the dispersant used for grinding of ultrafine ground calcium carbonate（GCC）, P(AA-AMPS） were prepared by using acrylic acid （AA） and 2-acrylamido-2-methyl propane sulfonic acid （AMPS） as monomers, ammonium persulfate as initiator, sodium hypophosphite as chain transfer agent, and the effect of P(AA-AMPS） on grinding was investigated. Results showed that P(AA-AMPS） demonstrated excellent performance and had a good grinding effect when it was prepared under the following polymerization conditions: mass ratio of monomers （AA-AMPS）= 4∶1, chain transfer agent dosage 7 wt% （based on the total monomers）, reaction temperature 80℃, reaction time 5.5 h, initiator dosage 4 wt % （based on the total monomers）. The products were characterized by FT-TR,13C-NMR，GPC and TG. When dispersant P(AA-AMPS） was used in the wet grinding process, the dispersant dosage and the adding mode of dispersant were investigated. Under the same grinding conditions, the grinding effect of P(AA-AMPS） was much better than that of the commercial products.