Nano-zinc oxide is a new type of highly functional and fine inorganic product facing the 21st century. Its particle size ranges from 1 to 100 nanometers, also known as ultrafine zinc oxide. Due to the finer particle size, the specific surface area increases dramatically, which causes the nano-ZnO to produce surface effects, small size effects, and macro quantum tunneling effects that are not available in bulk bulk materials. Therefore, nano-zinc oxide has special properties and new uses unmatched by general zinc oxide products in magnetic, optical, electrical, chemical, physical, and sensitivity applications, and in rubber, coatings, inks, pigments, fillers, catalysts, and high-end cosmetics. Areas such as medicine show a wide range of applications. This article will introduce in detail the preparation method, performance characterization, surface modification and currently applied fields of nano-zinc oxide produced by our company.
First, the preparation of nano-zinc oxide
Zinc oxide preparation methods are divided into three categories: the direct method (also known as the United States law), indirect method (also known as the French method) and the wet chemical method. At present, many commercially available zinc oxides are mostly direct or indirect products, and the particle size is micron, and the specific surface area is small. These properties greatly restrict their application fields and their performance in products. Our company adopts the wet chemical method (NPP-method) to prepare nanometer-scale ultrafine active zinc oxide. It can use various zinc-containing materials as raw materials, adopting acid leaching and leaching zinc. After many purifications, impurities in raw materials are removed, and then precipitated to obtain basic Zinc carbonate is finally baked to obtain nano zinc oxide. Compared with the previous preparation of nano-scale ultra-fine zinc oxide technology, this new process has the following technical innovations:
1. The principle of reaction kinetics under equilibrium conditions is combined with enhanced heat transfer technology to quickly complete the baking of basic zinc carbonate.
2. By adjusting the process parameters, various types of nano zinc oxide products with different purity, particle size and color can be prepared.
3. The process can use a variety of zinc-containing materials as raw materials, and convert it into high value-added products.
4. Typical green chemical processes are environmentally friendly processes.
Second, the performance of nano-zinc oxide characterization
The outstanding feature of nanoscale zinc oxide is that the product particles are nanometer-sized and have the dual characteristics of nanomaterials and traditional zinc oxide. Compared with traditional zinc oxide products, its large specific surface area, high chemical activity, product fineness, chemical purity and particle shape can be adjusted according to need, and has photochemical effects and better shielding UV performance, its UV shielding rate of up to 98 At the same time, it also has a series of unique properties such as antibacterial, antibacterial and anti-enzyme.
The analysis and test center of Tsinghua University analyzed the products by transmission electron microscopy. Nano-sized ZnO particles were spherical, with uniform particle size distribution, average particle size of 20 to 30 nm, and particle sizes of all particles below 50 nm. The BET specific surface area of ​​the nano zinc oxide powder was above 35m2/g as measured by the ST-A surface and aperture meter. In addition, rod-shaped nano-zinc oxide can also be produced by adjusting the preparation process parameters. The product was identified and tested by the Institute of Microbiology, Chinese Academy of Sciences. The results showed that adding 0.5% to 1% of nano-zinc oxide in a rich bacterial medium can effectively inhibit the growth of E. coli, and the rate of inhibition is more than 99.9%.
Third, the surface modification of nano-zinc oxide
Because nano-zinc oxide has the characteristics of large specific surface area and large specific surface energy, it is easy to agglomerate on the one hand; on the other hand, the surface of nano-zinc oxide has strong polarity and is not easy to disperse uniformly in organic media, which greatly limits its nano-effects. Play. Therefore, the dispersion and surface modification of nano-zinc powders become a necessary treatment method for nanomaterials before they are applied in the matrix.
The so-called nano-dispersion refers to the use of various principles, methods and means in a specific liquid medium (such as water), the various forms of aggregates composed of dry nanoparticles to reduce primary particles and make it stable and evenly distributed in the medium technology. The surface modification of nanopowders is based on the extension and extension of nanodispersion technology. That is, depending on the needs of the application, the surface of the dispersed nanoparticle is coated with a film of a suitable substance or the nanoparticles are dispersed in a certain way. Soluble solid support. The surface-modified nanopowder powders have a variety of surface properties such as adsorption, wetting, and dispersion. They can be automatically or easily dispersed in specific media, and are therefore very convenient to use. In general, there are three methods for modification of nanoparticles: 1. The surface of the particles is uniformly coated with a film of other substances, so that the surface properties of the particles change; 2. The use of charge transfer complexes (such as silane, titanic acid Ester and other coupling agents, as well as stearic acid, silicones, etc., are used as surface modifiers to chemically adsorb or chemically react with the surface of nanoparticles; 3. The use of corona discharge, ultraviolet light, plasma, radiation, and other high energy means on the surface of nanoparticles Modified.
According to the requirements of different application fields, appropriate surface modifiers or surface modification processes are selected to surface-modify the nano-ZnO, improve its surface properties, and increase the compatibility between the nano-particles and the matrix, and thus apply to each Fields, improve product performance and technical indicators.
Fourth, the application of nano-zinc oxide
Since the beginning of the preparation of nano-zinc oxide, the company has attached great importance to the development of its application technology. Through the in-depth research of the company's internal scientific research personnel and technical cooperation with relevant scientific research units, a series of important achievements have been made in the application technology of nano-zinc oxide. The main application areas of the current products are:
1. Rubber Tires Nano zinc oxide is an excellent vulcanizing agent in the rubber industry, especially in the production of transparent rubber products. As nano-zinc oxide can be combined with rubber molecules at the molecular level, it can improve the properties of rubber and improve the properties of finished products. Taking radial tires and other rubber products as an example, the use of nano-zinc oxide can significantly improve the thermal conductivity, wear resistance, tear resistance, and tensile strength of the product, and its use can save 35-50%, greatly reducing The product cost; in the processing technology, can extend the scorch time of the rubber, is extremely beneficial to the processing technology. Nano-zinc oxide is used in rubber products such as rubber shoes, rain boots and rubber gloves. It can greatly extend the service life of products and improve their appearance and color. It is used in transparent or colored rubber products and has traditional activities such as carbon black. The irreplaceable role of agents. Nano-zinc oxide is used in products such as air sealants and gaskets, and it also has a good effect on improving the wear resistance and sealing effect of products. At present, our company's nano zinc oxide has been well applied in many domestic large tire and rubber product companies.
2. Paint Coatings As people's requirements for coating color, coating performance, and environmental protection are improved, the application of nanomaterials in the coating industry has received increasing attention. The nanomaterials currently used in coatings include nano-titanium dioxide, nano-silica, nano-zinc oxide, and nano-calcium carbonate, among which nano-titanium dioxide and nano-silica have limited their application range and quantity due to their expensive price. The performance of nano-calcium carbonate is relatively single, and it plays a minor role in improving the anti-mold and anti-ultraviolet aging properties of the coating. Therefore, nano-zinc oxide occupies a greater advantage in the application of the coating with its excellent cost-effectiveness. Nano-zinc oxide has new properties and new uses unmatched by general zinc oxide. It can shield ultraviolet rays, absorb infrared rays, and sterilize and mold. Therefore, it can be widely used in architectural interior and exterior wall emulsion paints and other coatings. The thickening effect also helps to increase the stability of the pigment dispersion. Our company, through joint development with related research institutes, has successfully applied nano zinc oxide to waterborne coatings to produce nanometer zinc oxide modified coatings. The test shows that this modified coating has stain resistance, artificial aging resistance, and water resistance. The traditional mechanical mechanical properties such as alkali resistance, scrub resistance, hardness and adhesion have been greatly improved. In addition, the antibacterial and anti-mildew properties of nano-zinc oxide modified coatings are further studied.
3. Chemical fiber textiles Nanomaterials are used in chemical fiber textiles in two ways. One method is to directly add nanoparticles to the initial reaction solution of chemical fibers, and use conventional polymerization to synthesize functional fibers so that the nanoparticles are uniformly distributed in the fibers. Internally; another method is to formulate the nanoparticle as a post-finishing agent into the finishing solution of the fabric, adsorb the nanoparticle on the surface of the fiber by padding, or coat the nanoparticle with a certain binder. The fabric surface forms a functional coating that improves the fabric's performance. Jilin Chemical Fiber Group formulated nano zinc oxide modified by our company into the viscose fiber spinning solution to synthesize viscose fiber containing nano zinc oxide particles. The fiber was added into nano zinc oxide after spinning and weaving. Anti-ultraviolet fabrics were compared with plain fabrics without nano-ZnO, and the UPF (ultraviolet shielding coefficient) of the UV-resistant fabrics was twice that of the control fabrics. Our products can significantly improve the anti-ultraviolet and antibacterial functions of viscose fiber and synthetic fiber products, and are used in the production of anti-ultraviolet fabrics, antibacterial fabrics, parasols and other products. The anti-ultraviolet nanocolloids developed by our company have been tested on parasols by Hangzhou Paradise Umbrella Group Co., Ltd., China Institute of Metrology Science tests show that the UPF value (UV shielding coefficient) is 50, and its performance index has reached the Australian standard. Exceed EU standards.
4. Sunscreen cosmetics Due to the destruction of the Earth's ozone layer, the amount of UV radiation to the Earth's biosphere continues to increase, and the harmful effects of excessive UV radiation on human health are increasing. In order to withstand the damage of excessive ultraviolet radiation to human skin, various sunscreens have been developed to protect the skin. Due to the high activity of most organic sunscreens, they cause irritation to the skin and are easily decomposed after exposure to ultraviolet radiation. The effect of sunscreen is not long, and people have developed inorganic sunscreens such as nano-titanium dioxide and nano-zinc oxide. The study found that the protective function of nano-ZnO against UV is stronger than that of conventional nano-TiO2, and it has good protective effect against UV-A and UV-B, so the application of nano-ZnO in the cosmetics field is developing rapidly. Our company uses a special surface treatment technology to produce nano-scale zinc oxide sunscreen, it can absorb solar ultraviolet rays very effectively, especially to protect the body from UV-A and UV-B. Most of the traditional sunscreens work on UV-B, but they do not effectively withstand the longer UV-A wavelengths, and UV-A is increasingly considered to be associated with premature skin aging and skin cancer. Our company's zinc oxide average particle size is less than 50 nanometers, it can resist UV-A and UV-B most effectively, is a broad-spectrum anti-UV agent, non-toxic and harmless, is a real new generation of physical sunscreen.
5. Other areas With the deepening of people's understanding of the performance of nano-zinc oxide, the application of nano-zinc oxide is expanding. For example, the use of nano-zinc oxide in the ceramic industry can greatly reduce the sintering temperature of ceramic products, reduce the production process and reduce energy consumption, and give ceramic products antibacterial deodorant and decomposition of organic materials. The cleaning effect greatly improves the quality of the product. Because of its small size, large specific surface area, different bond state between the surface and the inside of the particle, nano zinc oxide enlarges the reaction contact surface and improves the catalytic efficiency. It is a manufacturing enterprise that prepares desulfurizers. The preferred material for chemical catalysts; nano-zinc oxide is also a good photocatalyst, under the irradiation of ultraviolet light, it can self-decompose the free-moving negative electrons, leaving positively charged holes, and activating the oxygen in the air to become Active oxygen, which reacts with a variety of organic chemicals, kills germs and viruses. In addition, nano-zinc oxide has also shown more and more broad application prospects in sensors, capacitors, fluorescent materials, wave absorbing materials, conductive materials and many other fields.
V. Conclusion
At present, the preparation technology of nano-zinc oxide has made some breakthroughs, and several domestic industrialized manufacturers have been formed in the country. However, the surface modification technology and application technology of nano-zinc oxide have not yet been fully matured, and the development of its application field has been greatly limited, and has constrained the formation and development of the industry. Although we have made great progress in the application of nano-zinc oxide in recent years, there is still much work to be done compared with the application level of developed countries and the potential application prospects of nano-zinc oxide. How to overcome the bottleneck of nano-zinc oxide surface treatment technology and accelerate its wide application in various fields has become an urgent problem for many nano-zinc oxide manufacturers.
Draining Rack,dish draining rack,kitchen dish draining rack,dish drainer rack,Dish Rack sink,etc. The materials used are 304 stainless steel, easy to clean, never rust!
China Kichen Rack,Sink Grid,Stainless Mesh Storage Baskets,Kitchen Wire Storage, we offered that you can trust. Welcome to do business with us.
Kichen Rack is made of high quality 304 stainless steel, This kind of material steel luxury, never rust, resist corruption, easily clean, safe, healthy and durable. Prevent rust or chemicals from contaminating food and damaging health
Fruit Vegetable Washing Draining Basket,Stainless Steel Kitchen Tool,Draining Rack, Draining Basket
Shenzhen Lanejoy Technology Co.,LTD , https://www.szbrassnuts.com