Department of Materials and Chemistry, Vrije Universiteit Brussel , Pleinlaan 2, 1050 Brussels, Belgium.
ACS Appl Mater Interfaces. 2014 Feb 26;6(4):2734-44. doi: 10.1021/am405278j. Epub 2014 Feb 4.
Modification of calcium carbonate particles with surfactant significantly improves the properties of the calcium carbonate coating on paper. In this study, unmodified and CTAB (hexadecyltetramethylammonium bromide)- and oleate-modified calcium carbonate nanoparticles were prepared using the wet carbonation technique for paper coating. CTAB (cationic surfactant) and sodium oleate (anionic surfactant) were used to modify the size, morphology, and surface properties of the precipitated nanoparticles. The obtained particles were characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, zeta potential measurements, thermal gravimetric analysis (TGA), and transmission electron microscopy (TEM). Coating colors were formulated from the prepared unmodified and modified calcium carbonates and examined by creating a thin coating layer on reference paper. The effect of calcium carbonate particle size and surface modification on paper properties, such as coating thickness, coating weight, surface roughness, air permeability, brightness, whiteness, opacity, and hydrophobicity, were investigated and compared with commercial ground (GCC) calcium carbonate-coated papers. The results show that the obtained calcium carbonate nanoparticles are in the calcite phase. The morphology of the prepared calcium carbonate nanoparticles is rhombohedral, and the average particle diameter is less than 100 nm. Compared to commercial GCC, the use of unmodified and CTAB- and oleate-modified calcium carbonate nanoparticles in paper coating improves the properties of paper. The highest measured paper properties were observed for paper coated with oleate-modifed nanoparticles, where an increase in smoothness (decrease in paper roughness) (+23%), brightness (+1.3%), whiteness (+2.8%), and opacity (+2.3%) and a decrease in air permeability (-26%) was obtained with 25% less coat weight. The water contact angle at a drop age time of 10 min was about 112° for the paper coated with oleate-modified nanoparticles and 42° for paper coated with CTAB-modified nanoparticles compared to 104° for GCC-coated paper.
用表面活性剂对碳酸钙颗粒进行改性，可显著改善碳酸钙在纸张上的涂层性能。本研究采用湿碳化技术制备了未经改性和 CTAB（十六烷基三甲基溴化铵）及油酸钠改性的碳酸钙纳米颗粒，用于纸张涂层。CTAB（阳离子表面活性剂）和油酸钠（阴离子表面活性剂）被用于修饰沉淀纳米颗粒的粒径、形貌和表面性质。采用 X 射线衍射（XRD）、傅里叶变换红外（FT-IR）光谱、Zeta 电位测量、热重分析（TGA）和透射电子显微镜（TEM）对所得颗粒进行了表征。由制备的未改性和改性碳酸钙配制了涂料色浆，并在参考纸上涂覆了一层很薄的涂层来进行检测。考察了碳酸钙粒径和表面改性对纸张性能（如涂层厚度、涂层重量、表面粗糙度、透气性、亮度、白度、不透明度和疏水性）的影响，并与商用研磨碳酸钙（GCC）涂层纸进行了对比。结果表明，所得到的碳酸钙纳米颗粒呈方解石相。制备的碳酸钙纳米颗粒的形态为菱形，平均粒径小于 100nm。与商用 GCC 相比，在纸张涂层中使用未改性和 CTAB 及油酸钠改性的碳酸钙纳米颗粒可改善纸张的性能。用油酸钠改性纳米颗粒涂覆的纸张的性能最高，其中平滑度（粗糙度降低）提高了 23%，亮度提高了 1.3%，白度提高了 2.8%，不透明度提高了 2.3%，而涂层重量减少了 25%，透气性降低了 26%。用油酸改性纳米颗粒涂覆的纸张的水滴接触角在 10 分钟时约为 112°，而用 CTAB 改性纳米颗粒涂覆的纸张的水滴接触角为 42°，相比之下，用 GCC 涂覆的纸张的水滴接触角为 104°。
