调节pH控制载银纳米TiO2表面包覆的PMMA

Surface Modification of TiO_2 Containing Ag^+ with Poly (Methyl Methacrylate) Encapsulation by Controlling pH

测定了十二烷基磺酸钠(SDS)在载银离子纳米TiO2颗粒表面的等温吸附曲线,在SDS达到临界胶束浓度(CMC)时,研究了pH=2.0(等电点以下)和pH=7.0(等电点以上)时甲基丙烯酸甲酯(MMA)在TiO2粒子表面的乳液聚合。采用改性前后Ti O2的Zeta电位的变化、红外光谱(FT-IR)及差热分析(DTA)等表征方法评价了改性效果。结果表明:PMMA成功包覆到TiO2表面,包覆率达17.8%,载银TiO2的表面由亲水变为亲油;在pH=2.0,cSDS=5.0 mmol/L时,Ag+的脱附量只有8%。

Absorption isotherms of anionic surfactant sodium dodecylsulfate （SDS） on surface of titanium dioxide nanoparticles were measured. The investigation about the emulsion polymerization of methyl methacrylate （MMA） on the surface of TiO2 was carried out at pH values of 2.0 and 7.0, respectively, at the critical micelle concentration （CMC） of SDS. The surface properties of the modified TiO2 were studied by Zeta-potential, FT-IR and DTA, respectively. Experimental results show the TiO2 particles are encapsulated by PMMA successfully with the grafting efficiency of 17. 8%. The surfaces of the particles become hydrophobic. The amount of Ag^＋ loss is only 8% when pH and CSDS are 2.0 and 5.0 mmol/L, respectively.