| 醇酯化法改性白炭黑,通常在添加催化剂,一定溶剂体系下进行改性。论文在微负压(1kPa)条件下,无催化剂,无溶剂体系中讨论对纳米白炭黑进行有机表面改性。通过对比,后者的改性效果明显好于前者。论文对新工艺得到的改性白炭黑产品采用红外光谱、扫描电子显微镜、热重分析仪等检测手段进行了表征并探讨了改性工艺条件的优化,同时对反应过程的动力学进行了初步研究。通过四因素(改性温度A,改性时间B,改性剂用量C,搅拌速率D)三水平正交实验,得出白炭黑表面改性的优化条件：改性温度160℃,改性时间3h,改性剂用量70mL,搅拌速率50r／s,在优化条件下改性白炭黑的特性粘度为71.21mPa·s;对改性效果影响的大小为：A>C>B>D.通过选取对改性效果影响较大的三个因素(A,B,C)二次回'正交实验进一步对改性工艺条件进行优化,建立白炭黑表面有机改性的回'方程模型：y=69.52+0.76x1-1.27x2+1.51x1x2+1.62x2x3+x12+1.05x22+0.86x32通过对模型求极值得出最优改性工艺条件：改性剂用量71.76mL改性温度144.13℃、改性时间3.55h。在最优改性工艺条件下,改性白炭黑的特性粘度值为70.71mPa·s,对回'方程进行验证,通过回'方程得出的回'值与实验值的比较得出其平均相对误差为,1.97%,表明通过二次回'正交设计得出的模型是可行的。由于正辛醇改性白炭黑是液-固非催化反应,论文选取收缩未反应芯动力学模型对改性反应过程的动力学进行了研究。通过数据的分析与计算,得出改性反应由内扩散过程控制,动力学方程为：k=4.76exp(-37.57/RT),表面活化能Ea=37.57kJ/mol。 Alcohol esterification that modify silica usually adds catalyst in certain solvent system. The paper discusses the nano-silica organic surface modification in micro-vacuum conditions, without catalyst, solvent-free systems. Through the contrast between the two, the latter modification is obviously better than the former.The paper characterizes modified silica that was produced by new process by infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis, and other means of detection and discussed the optimization of the modified process conditions, meanwhile, study preliminarily the kinetics of the reaction process.Through four factors (temperature modified A, modified time B, the amount of modifier C, stirring rate D) three level orthogonal experiment, the obtained optimum conditions of surface-modified silica:modified temperature160℃, modified time3h, modified dosage70mL, stirring speed50r/s, in optimum conditions, the characteristic viscosity of modified silica degree71.21mPa-s; the effect to the reaction is:A> C> B> D.Selecting the three factors (A, B, C) that are greater impact on modification effect to do the quadratic regression orthogonal experiment to further optimize the modified process conditions, the regression equation was established: y=69.52+0.76x1-1.27x2+1.51x1x2+1.62x2x3+x12+1.05x22+0.86x32Results indicate that the optimum conditions of synthesis:modified dosage71.76mL, modified temperature144.13℃, modified time3.55h. in the optimal modified process conditions, the characteristic viscosity of modified silica is70.71mPa-s, Compared the calculated values with experiment values, the relative error is1.97%, which indicate that the quadratic regression orthogonal design obtained by the model is feasible. |
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