| In modern society, with changes of people’s living concept and improvement of environmental awareness, more and more people are paying great attention to beautiful living condition and environmental protection and pursuiting elegant living environment. As a result, most of the buildings have been adopted CaiQi coating to replace exterior wall tiles, and most indoor walls are also decorated by interior wall coating. However, with the extension of time, exterior CaiQi will be attached to a layer of dust on the surface coating, which leads to the appearance of dirty and color dim. Further more, some indoor interior wall coating may breed bacteria and other microorganisms due to high humidity, which causes a great threat to human health. In this paper, a kind of hydrophobic antibacterial material was produced to solve this problem by using its self cleaning and antibacterial ability. The hydrophobic antibacterial material was synthesized by ultraviolet catalytic method, using silica (SiO2) and titanium dioxide silver (Ag/TiO2) as raw materials, vinyltrimethoxysilane (VTMO) as the hydrophobic modification agent, and diphenyl(2,4,6-trimethylbenzo-yl)-phosphine oxid (TPO) as ultraviolet light catalyst. The main research contents include the preparation of SiO2 hydrophobic powders, Ag/TiO2 hydrophobic powders and hydrophobic antibacterial SiO2/Ag/TiO2 composite powders, and their structure and properties characterization, such as crystal composition, hydrophobici-ty, antibacterial properties and so on. The research results and conclusions are as follows:(1) Prepration and characterization of hydrophobic SiO2 powders. Hydrophobic SiO2 powders were prerared by in-situ surface modification, using SiO2 powders as raw materials, VTMO as surface modification agent. Factors affecting hydrophobic property of modified SiO2 powders were investigated, the parameters related to preparation of modified SiO2 powders were determined, and the structure and hydrophobic property of modified SiO2 powders were also characterized. The results showed that a kind of super hydrophobic SiO2 powders, with a static contact angle of 162.9°, could be prepared with VTMO/SiO2 ratio of 10:1, reaction time of 2.5h, the drying time of 10h, and the drying temperature of 150℃. The hydrophobic SiO2 powders have double micro structure, uniform size and good thermostability.(2) Prepration and characterization of hydrophobic Ag/TiO2 powders. Super hydrophobic Ag/TiO2 powders were prepared by in-situ surface modification, using Ag/TiO2 powders as raw materials, VTMO as surface modification agent. The factors affecting modification of Ag/TiO2 powders were investigated, and the ideal preparation conditions were determined. And the structure and properties of modified Ag/TiO2 powders were also characterized. The results showed that a kind of super hydrophobic Ag/TiO2 powders,with the static contact angle of 168.5°, could be prepared with VTMO/(Ag/TiO2) ratio of 18:1, reaction time of 4h, reaction temperature of 40 ℃, and drying temperature of 150℃. Under conditions mentioned above, the obtained hydrophobic Ag/TiO2 powders have double micro structure, uniform size and an ideal graft rate.(3) Prepration and characterization of hydrophobic SiO2/Ag/TiO2. Firstly, modified SiO2 and Ag/TiO2 powders were synthesized by in-situ surface modification under the optimal conditions mentioned above respectively. Then, the hydrophobic SiO2/Ag/TiO2 powders were synthesized by ultraviolet catalytic method, the alcohol solution of two super hydrophobic powders were polyreacted under ultraviolet irradiation and in the presence of TPO. Factors affecting synthesis of hydrophobic SiO2/Ag/TiO2 powders were investigated. And the structure and properties of obtained hydrophobic SiO2/Ag/TiO2 powders were characterized. The results showed that a kind of super hydrophobic SiO2/Ag/TiO2 composite powders, with a static contact angle of 157.7°, could be prepared under ultraviolet irradiation and in the presence of TPO, at temperature of 35℃ for 1.0h, with drying temperature of 130℃. And it is also founded that the powder particle size increased generally with development of polymerization.(4) Antibacterial test. Escherichia coli and Staphylococcus aureus were used as subjects to test the antibacterial properties of modified SiO2 powers, Ag/TiO2 powers and SiO2/Ag/TiO2 powders by the minimum bacteriostasis concentration (MIC) and the bacteriostatic circle methods. The results of MIC test showed that the modified SiO2 powders do not have antibacterial properties, the modified Ag/TiO2 powders and SiO2/Ag/TiO2 composite powders have antibacterial properties. The MIC of hydrophobic SiO2/Ag/TiO2 powders against Escherichia coli and staphylococcus aureus were both 120μg/mL and that of hydrophobic Ag/TiO2 powders were 100μg/mL. The inhibition zone test showed that the antibacterial properties of hydrophobic SiO2/Ag/TiO2 powders were weaker than that of hydrophobic Ag/TiO2 powders, the same as the conclusion of MIC test. |
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