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

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。

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

In order to enable the white chromogenic particles used in E-ink to disperse well in the organic medium, the surface modification of TiO_2 was treated by ultrasonic with silane coupling agent(γ-methacrylic acyloxy propyl trimethoxy silane)in the water system. The modified TiO_2 had changed hydrophilicity to lipophilieity. The effects of silane coupling agent dosage, pH and ultrasonic treatment time were investigated on the lipophilic degree of TiO_2 particle. The results showed that the lipophilicdegree of the modified TiO_2,could reach 50.51% in the optimal modifying condition that m(silanecoupling agent):m(TiO_2)=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 TiO_2 particle. Forty percent of the modified TiO_2 had been subsided in ethanol after 24 h and then remained stable. The pristine TiO_2 had been all subsided after 8 h. The Zeta potential of the surface modified TiO_2 particles in ethanol solution Was improved to -36.90 mV. After the soxhlet extraction, the lipophilic degree of the modified TiO_2 could still reach 47%. The binding force between TiO_2 and silane coupling agent Was strong.