白炭黑的表面改性和性能研究

为提高白炭黑对有机高分子的亲和性,利用偶联剂同时拥有亲油基和亲水基的结构特性,对白炭黑颗粒表面进行改性.考察了改性时间、温度、pH和偶联剂与白炭黑的质量比对白炭黑表面改性情况的影响.通过红外光谱、热失重、氮气吸脱附、接触角、活化度及沉降体积测试等手段对改性前后白炭黑结构及改性效果进行表征.结果表明,γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)的改性效果明显优于γ-巯丙基乙氧基双(丙烷基-六乙氧基-硅氧烷)(Si747)和双-(γ-三乙氧基硅基丙基)四硫化物(Si69).以无水乙醇为改性剂,当KH570与白炭黑的质量比为14%、改性温度为50℃、pH为7、改性反应6 h时,活化度达到最大.改性后偶联剂接枝在白炭黑表面,亲水性降低、分散性提高,表面浸润性得到明显改善,拓宽了白炭黑在工业中的应用范围.

Study on surface modification and properties of silica

In order to improve the affinity of silica to organic polymers,the surface of silica particles was modified by coupling agent with the structure characteristics of lipophilic and hydrophilic groups.The effects of modification time,temperature,pH and the mass ratio of coupling agent to silica on the surface modification of silica were investigated.The structure and modification effect of silica before and after modification were characterized by means of infrared spectrum,thermogravimetry,nitrogen adsorption desorption,contact angle,activation degree and sedimentation volume test.The results show that the modification effect of γ-methylpropenylpropyltrimethoxysilane(KH570)is better than that of γ-mercaptopropylethoxybis(propane hexaethoxy siloxane)(Si747)and bis-(γ-triethoxysilypropyl)tetrasulfide(Si69).Taking anhydrous ethanol as modifier,when the mass ratio of KH570 to silica is 14%,the modification temperature is 50℃,the pH is 7,and the modification reaction is 6 hours,the activation degree reaches the maximum.After the modification,the coupling agent is grafted on the surface of silica,the hydrophilicity is reduced,the dispersibility improved,and the surface wettability is obviously improved,which widen the industrial application scope of silica.