棕榈酸对纳米碳酸钙表面改性的室温工艺研究

Surface modification technique of nano-sized CaCO_3 by palmitic acid at room temperature

为了解决纳米碳酸钙在有机介质中的分散问题和进一步降低反应能耗,在室温条件下对棕榈酸表面改性纳米碳酸钙的工艺进行了研究。探讨了不同的改性剂、改性剂用量和氯仿溶剂的回收再利用等条件对纳米碳酸钙改性的影响并优化了改性工艺条件。最佳的改性工艺条件:以氯仿作为改性溶剂;以棕榈酸作为改性剂,改性剂用量为3.5%(质量分数);改性温度为室温。在此工艺条件下,改性后纳米碳酸钙的活化度为95%,在液体石蜡中的沉降体积为2.72 mL/g,表明改性后产品的疏水性和亲油性均得到明显提高。氯仿作为改性溶剂可以回收并重复利用。红外光谱显示纳米碳酸钙和改性剂棕榈酸已经形成了牢固的化学键。透射电镜结果表明,改性后的纳米碳酸钙在有机溶剂中的分散性被提高。

In order to solve the problem of nano-sized CaCO3 dispersion in organic media and to reduce the reaction energy consumption,process of surface modification of nano-sized CaCO3 by using palmitic acid as modifier at room temperature was studied.Influences of process conditions,such as different modifiers,dosage of modifier,and recycle of chloroform on modification of nano-sized CaCO3,were discussed and process conditions were optimized at same time.Optimal modification conditions were as follows：chloroform as modification solvent,palmitic acid as the modifier,dosage of palmitic acid was 3.5%（mass fraction）;and modification temperature was room temperature.Under those conditions nano-sized CaCO3 with activation degree of 95% could be obtained and its settlement volume in liquid paraffin was 2.72 mL/g,which demonstrated the product′s hydrophobicity and lipophilicity were both improved after modification.In addition,chloroform can be recycled as solvent.FT-IR analysis showed the palmitic acid modifier and nano-sized CaCO3 had formed strong chemical bonds.TEM results indicated the dispersion of modified nano-sized CaCO3 in organic solvents was also improved.