载银纳米二氧化钛粉在口腔用聚氨酯中的抗菌性研究

目的:探讨载银纳米二氧化钛粉在口腔用聚氨酯中的抗菌效果及对材料物理性能的影响。方法:取热塑性聚氨酯(TPU),分别加入质量分数为1%、2%、3%的载银纳米二氧化钛粉,制成长条和圆片形样本,观察样本硬度、强度、拉伸强度等物理性能。取TPU粉末,分别加入质量分数为1%、2%、3%的载银纳米二氧化钛抗菌剂,制成抗菌材料样本,滴入菌液,以薄膜密贴法进行抗菌性能实验,观察抗菌效果及样品色泽。结果:1%、2%、3%样本的强度、硬度和拉伸强度均无明显变化,与空白对照组比较无统计学差异(P>0.05)。3%样本白色念珠菌抗菌率(95.4%)高于1%、2%样本,血链球菌抗菌率(33.0%),低于50%。结论:聚氨酯中加入载银纳米二氧化钛对材料物理性能影响不大,3%质量分数的载银纳米二氧化钛对白色念珠菌具有较强的抗菌作用且不会影响血链球菌,有助于维持口腔微生态平衡,值得推广使用。

La_2O_3/Al_2O_3/TiO_2纳米复合粉体的制备及其耐温性能的研究

以TiCl_4、La_2O_3、Al片为原料,采用液相共沉淀法制备了La_2O_3/Al_2O_3/TiO_2纳米复合粉体,采用DSC-TG、XRD、TEM技术对该纳米复合粉体进行了表征。结果表明:纳米TiO_2粉体经La_2O_3掺杂和Al_2O_3复合后,其耐温性能得到显著提高,该复合粉体经900℃煅烧后,粒径在32nm左右,锐铁矿含量约为77.2％(mol％)

Effect of Dispersity and Porous Structure of TiO2 Nanopowders on Photocatalytic Destruction of Azodyes in Aqueous Solutions

Photocatalytic activity of TiO2 nanopowders of anatase modification with various particle sizes and specific surface areas has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue and direct blue 2C azodyes. By means of scanning electron microscopy and low-temperature N2 adsorption method, it was found that TiO2 nanopowders have the particles size of 5-120 nm with the specific surface area of 15-120 m2·g^-1. The used TiO2 samples are characterized by mesoporous structures with average pore size of 4.3-14.9 nm. The photocatalytic activity of TiO2 was evaluated via decolorization of azodyes solutions. It was shown that the efficiency of decolorization symbatically changes with the dye adsorption value on TiO2 surface and the degree of decolorization rises when the surface area of TiO2 nanopowders increases. It was found that TiO2 photocatalytic activity essentially depends on adsorption interactions between the dye molecules and catalytic active centers on TiO2 surface, and these interactions, in turn, are greatly affected by pH of the solution.