电子墨水用TiO_2显色颗粒的表面改性及其分散性能的研究

Surface Modification of Titanium Dioxide Chromogenic Particles Used in E-ink Surface and Study of Its Dispersancy

为使电子墨水用TiO2显色颗粒能较好地悬浮在有机介质中,利用超声波处理方法,采用硅烷偶联剂(γ-甲基丙烯酰氧基丙基三甲氧基硅烷)在水体系中对TiO2进行表面改性,得到亲油性的TiO2颗粒。研究了硅烷偶联剂用量、pH、超声波处理时间对TiO2亲油化度的影响。实验结果表明,当m(硅烷偶联剂)∶m(TiO2)=3∶10,pH=6,超声波处理时间为30 min时,改性TiO2的亲油化度达到50.51%。傅立叶变换红外光谱(FTIR)图表明硅烷偶联剂已接枝到TiO2颗粒表面。改性TiO2在乙醇中静置24 h只有40%发生沉降,之后基本保持稳定,而未经改性的TiO2仅8 h就几乎完全沉降。经表面改性后TiO2颗粒在乙醇溶剂中的Zeta电位提高到-36.90mV。索氏抽提后,改性TiO2的亲油化度仍能达到47%,TiO2和硅烷偶联剂之间结合力较强。

In order to enable the white chromogenic particles used in E-ink to disperse well in the organic medium,the surface modification of TiO2 was treated by ultrasonic with silane coupling agent（γ-methacrylic acyloxy propyl trimethoxy silane） in the water system.The modified TiO2 had changed hydrophilicity to lipophilicity.The effects of silane coupling agent dosage,pH and ultrasonic treatment time were investigated on the lipophilic degree of TiO2 particle.The results showed that the lipophilic degree of the modified TiO2 could reach 50.51% in the optimal modifying condition that m（silane coupling agent）∶m（TiO2）=3∶10,pH was 6 and the modification time was 0.5 h.FTIR showed that the silane coupling agent was chemically bonded to the TiO2 particle.Forty percent of the modified TiO2 had been subsided in ethanol after 24 h and then remained stable.The pristine TiO2 had been all subsided after 8 h.The Zeta potential of the surface modified TiO2 particles in ethanol solution was improved to-36.90 mV.After the soxhlet extraction,the lipophilic degree of the modified TiO2 could still reach 47%.The binding force between TiO2 and silane coupling agent was strong.