脂肪酸类表面活性剂包覆改性硝酸铵防吸湿性能研究

发布时间：2018-04-24 03:27

  本文选题：硝酸铵 + 表面活性剂　； 参考：《南京理工大学》2017年硕士论文

【摘要】：本文以工业品硝酸铵颗粒为原料,A和B混合溶剂为介质,设计的十八酸为包覆剂,采用吸附包覆的方法,得到十八酸吸附包覆硝酸铵颗粒的最佳包覆工艺条件和包覆样品,来达到降低硝铵盐颗粒吸湿性的目的。首先,选择仅含C、H、O、N的4种不同极性基团及其不同脂肪烃链长的表面活性剂作为包覆材料,以吸湿率降幅和包覆层质量分数为指标,考察不同原料样品准备的实验操作和环境条件对硝酸铵吸湿性的影响用于改进包覆工艺条件,进而初步比较不同表面活性剂包覆硝酸铵降低其吸湿性的效果,筛选出防吸湿性效果最好的表面活性剂作为下阶段实验所需的包覆材料。其次,展开全面包覆工艺优化实验,通过初步探索实验,考察所选表面活性剂投加量、溶剂配比、反应温度、反应时间等因素对包覆效果的影响,得到较佳工艺条件范围。进而,对上述各因素进行工艺优化实验和工艺条件因素的影响实验,研究得到以十八酸为包覆剂的最佳工艺条件和各因素对硝酸铵颗粒吸湿率降幅和包覆层质量分数的影响规律。最后,将上述得到的最佳工艺条件进行工艺为20g/批放大实验,对得到的最佳包覆样进行SEM和FTIR表征。结果表明,经溶剂除水和冷却方式工艺方式改进,包覆样吸湿率降幅提高3%-5%。吸附包覆实验研究所得最佳包覆工艺为,以十八酸为包覆材料,以5.0g硝酸铵为原材料,投加量为2.00g,在混合溶剂中搅拌进行表面吸附包覆。其中,A和B溶剂体积配比为15mL:15mL,反应温度55℃,反应时间1.5h,自然冷却6h后出料,减压抽滤所得包覆样品并干燥。取5.0g包覆样品在温度35℃,相对湿度68%条件下吸湿24h,得到吸湿率降幅为34.4%,包覆层质量分数为0.76%。最佳工艺条件按等比例放大到20g/批,经放大工艺所得的20g包覆样品,在温度35℃,相对湿度92%条件下吸湿24h,得到吸湿率降幅29.7%,包覆层质量分数为1.01%。上述两个量级的实验结果,包覆的硝酸铵的吸湿率降幅超过目前同类文献报道的最高值。SEM表征发现改性后的样品表面变得致密光滑,表面孔洞和裂纹减少;FTIR表征可知表面活性剂吸附包覆在颗粒表面。本文在已有文献基础上通过改进包覆工艺方法和条件,使包覆改性后的硝酸铵颗粒防吸湿效果明显提高,可为硝酸铵防吸湿包覆工艺的进一步研究和其它硝铵盐改性研究提供一定的实验基础。
[Abstract]:In this paper, using ammonium nitrate particles as raw materials and octadecanoic acid as coating agent, the optimum coating conditions and coating samples of ammonium nitrate particles adsorbed by octadecanoic acid were obtained. To reduce the hygroscopicity of ammonium nitrate particles. Firstly, four kinds of surfactants with different polarity groups and different fatty hydrocarbon chain lengths were selected as coating materials. The decrease of moisture absorption rate and the mass fraction of coating layer were taken as indexes. The effects of the preparation of different raw materials and the environmental conditions on the moisture absorption of ammonium nitrate were investigated in order to improve the coating conditions, and to compare the effect of different surfactants coated with ammonium nitrate on the hygroscopicity of ammonium nitrate. The best anti-moisture absorbent surfactant was selected as the coating material for the next stage of the experiment. Secondly, the optimization experiment of comprehensive coating process was carried out, and the effects of the dosage of surfactant, the proportion of solvent, reaction temperature and reaction time on the coating effect were investigated, and the better technological conditions were obtained. Furthermore, the process optimization experiments and the effects of technological conditions on the above factors are carried out. The optimum process conditions of octadecanoic acid as coating agent and the influence of various factors on the decrease of moisture absorption rate of ammonium nitrate particles and the mass fraction of coating layer were obtained. Finally, the optimal process conditions were obtained by 20g/ batch amplification experiment, and the optimal coating samples were characterized by SEM and FTIR. The results show that the decrease of moisture absorption rate of the coated sample is increased by 3%-5% through the improvement of solvent dewatering and cooling process. The optimum coating technology was obtained by adsorption coating experiment. The coating was prepared by mixing octadecanoic acid as coating material, ammonium nitrate as raw material and adding amount of 2.00g in mixed solvent. The solvent volume ratio is 15ml: 15mL, the reaction temperature is 55 鈩，

本文编号：1794951