纳米二氧化硅表面接枝氮氧自由基的改性研究

Study on the Modification of Nano-Silica Surface Grafted on Free Radical of Nitrogen Oxide

采用自制的氮氧自由基改性三乙氧基硅烷,与纳米二氧化硅(SiO_2)在无水条件下进行缩合反应制得表面接枝氮氧自由基的SiO_2。采用热重分析研究了不同反应时间、反应温度以及IPTS-TEMPO用量对SiO_2表面接枝率的影响,并利用透射电镜对SiO_2表面接枝结果进行了表征。结果表明,当反应温度110℃,反应时间24 h,IPTS-TEMPO质量分数为50%时,纳米SiO_2的表面接枝率较高。改性后的SiO_2无粒子团聚现象。

The silicon dioxide （SiO2 ） with surface grafted free radical of nitroxide was prepared by con- densation reaction with self-made triethoxysilane modified by free radical of nitroxide （ IPTS - TEMPO ） and nano-silica under the condition of no water. The influence of the reaction time, temperature and the amount of IPTS -TEMPO on the surface grafting rate of SiO2 were studied by thermogravimetric analysis. And the SiO2 surface grafting result was characterized by scanning election microscopy. Result show that the surface graft rate of nano -SiO2 is higher, when the temprature is 110 centigrade, reaction time is 24 h, and the mass fraction of IPTS -TEMPO is 50%. The modified SiO2 is particle agglomeration-free.