Nano Au for Biomedical Applications

The biomedical field is a brand-new research field formed by integrating the methods and theories of medicine, biology and other related disciplines. Its research contents include bio-medicine, clinical applied chemistry, cytology and immunology, etc. With the rapid development of technology, many cutting-edge research and inventions in hot areas have played an important role in the field of bio-medicine, such as digital holography, virtual reality, and nanotechnology. It can be said that bio-medicine is an important area related to human beings. Studies have shown that surface-modified nano-gold particles can play a very important role in cell imaging, drug carriers, and many other aspects, its performance is closely related to the structure of nano-gold composition, morphology, size and size. More attention is paid to the appearance of gold nano structures such as rods and spheres.

 

Nanomaterials are materials in which at least one dimension in the three-dimensional space is in the nanoscale range or consists of them as basic units. Nano gold is a kind of nano material and is a gold nano particle with a diameter of 1-100nm. Nano-gold particles play an important role in molecular detection, photo-thermal therapy, tumor diagnosis, and green catalysis. In the following, I will give a detailed review of the field of bio-medicine.

 

  1. Application in bio-moleculardetection and identification

The emergence of nano gold immunolabeling technology in 1971 made it possible to see the great potential of nano gold as an immunological marker. After decades of continuous development, the immunolabeling technology using nanogold as a marker has basically matured. Has become one of the four major immunolabeling technologies. With the advancement of science and technology, people have a deeper understanding of the physicochemical properties of Gold nanoparticles dispersion , thus further expanding the biometric detection technology using nano gold as a marker. At present, nanogold is mainly used in biological detection to detect nucleic acids and proteins. Based on its unique surface plasmon resonance effect, catalytic properties, and high-density properties and other physicochemical properties, nano gold has unparalleled advantages in other areas of biological detection, and it has great potential for early diagnosis of tumors.

 

  1. Application in cell imaging and photothermotherapy

The strong scattering of nano gold particles was first used by researchers in the field of nano gold cell imaging and is still the most commonly used nano gold cell imaging method. As long as the diameter of the nano gold particles is greater than 20nm, it can be easily observed in a dark field scattering microscope. Compared with common fluorescent groups, nano gold particles can stably scatter light for a long time without being bleached. At the same time, due to the surface plasmon resonance effect of the nano-gold particles, the molecular electromagnetic field signal will be enhanced if it is within the nano gold surface or within 10 nm from the nano gold surface. Through the extraction of these enhanced electromagnetic field signals, Can be applied to bio-imaging technology. Because nano gold’s two-photon luminescence imaging technology has a much higher signal-to-noise ratio than dark-field microscopy, it has a very high potential for intracellular imaging. In addition, nano-gold particles can produce high thermal behavior by absorbing near-infrared light, a feature that makes it play a significant role in photothermal therapy in medicine.

 

  1. Application in drug delivery and controlled release

The specific surface area of ​​nano gold is relatively large, and its surface is easily modified. The drug can easily bind to the nano gold surface after chemical bonds and non-chemical bonds, thereby forming a nano gold drug-loading system. The drug-loading system formed by nano gold has the characteristics of increasing drug solubility, increasing cytotoxicity, and increasing drug stability. Currently, nano gold has been widely used in various fields of bio-medicine as a carrier for various types of drugs. The use of nano gold as a drug carrier can both protect the drug, increase the activity of the drug, reduce the amount of the drug used, and reduce the medical cost.

Related Tags: Nano gold colloid  Nano Gold dispersion

Carbon nanotubes are used in batteries

Lithium iron phosphate power cell is the most potential lithium-ion power battery for electric vehicles in the market, which has the advantages of good safety, long cycle life, and high energy density. However, lithium iron phosphate has poor electrical conductivity and conductive agent must be added to improve its conductivity. Most commonly used conductive agents are carbon black and graphite, which is cheap. However, in the process of multiple charging and discharging, the expansion and contraction of graphite materials reduces the contact between graphite particles, increases the gap, and even separates from the collector fluid and no longer participates in the electrode reaction. Therefore, the choice of conductive agent has an important role in improving battery performance.
At present, carbon nanotubes(CNTs) have gained wide attention in the application of conductive agents due to their excellent physical and chemical properties. The conductive mechanism of carbon nanotubes is that because they belong to one-dimensional nanomaterials, the length-diameter ratio is relatively large, which is good for the formation of conductive networks, and can improve the bonding between active materials and their collective flow, also it play the role as a physical adhesive. At the same time, it has excellent mechanical properties and chemical inertia, and it also has good thermal conductivity. It can improve the specific capacity and cycle life of the battery and improve the high temperature performance. It is an ideal new type of conductive material for lithium ion batteries.
In the experiment, multi-wall carbon nanotubes were applied to the positive and negative poles of lithium iron phosphate batteries respectively, and different tired batteries were prepared. The conventional performance and doubling rate were tested, and they were compared with the cores prepared by ordinary conductive carbon black. The test results show that, The electric core of high-conductive multi-wall carbon nanotubes added to the carburetor nanotubes has better conventional performance and double discharge performance than the conventional core, and the double discharge effect of both positive and negative poles is the best, followed by the addition of negative poles. The addition of MWCNTs to the negative electrode also shows the same situation. After the negative electrode capacity increases, it can embed more lithium ions when charging, which is conducive to the increase of discharge capacity, and because multi-walled carbon nanotubes have better electronic transport capabilities. In addition, more continuous conductive networks are formed in the click, which reduces the number of active substance particles encouraged. Also, the positive pole is added. The carbon nanotube, in high purity, is easy to disperse, has a low resistivity and can reach a resistivity of 650 μΩ. M, which is very suitable for battery use.
Multi-wall carbon nanotubes for lithium iron phosphate batteries
The addition of carbon nanotubes also has an important influence on the electrochemical performance of lead acid battery negative plates. After adding CNT, it can increase the amount of liquid absorption of the electrode, improve the transmission performance of the electrolyte in holes, and also improve the negative electrode conductivity, enhance the charging and discharging ability, improve the morphology and utilization rate of the active material, and slow down the salt of the negative electrode. In partial charge state, the rapid discharge cycle life of the plate can be extended. The negative electrode is added to the CNT battery prepared by 0.5 % CNT. When the SBAS0101 is rapidly charged and discharged under 50 % charge state, the battery discharge termination voltage is increased and the cycle life is extended.

Related Tags:Transparent Silver Colloid  Colloidal Gold

Conductive and antistatic nanomaterials commonly used in the textile and chemical fiber industry

The development of nanotechnology and nanomaterials provides new ways and ideas for the development of anti-static products. The special conductivity, electromagnetic properties, super-absorb ability and wide band of nanomaterials have created new conditions for the research and development of conductive absorbing fabrics. Due to the electrostatic effect, chemical fiber clothing and chemical fiber carpets have a discharge effect when rubbed, and at the same time, it is easy to adsorb dust, which brings a lot of inconvenience to the user; some operating platforms, cabin welding and other first-line work sites are prone to sparks due to static electricity, causing an explosion. . From the perspective of safety, it is an important task to improve the quality of chemical fiber products and solve the problem of static electricity.

If connected to the resin with nano-powders with semiconducting properties ( such as nano-TIO2, nano-ZNO and nano-FE2O3) , the resin will have electrostatic shielding performance, which greatly reduces the electrostatic effect and greatly improves the safety factor.

The anti-static master batch prepared by dispersing the multi-walled carbon nanotubes in the self-made anti-static carrier PR-86 can produce an anti-static PP fiber with excellent performance. The presence of multi-walled carbon nanotubes enhances the degree of polarization of the microfiber phase and the antistatic effect of the antistatic master batch. The antistatic properties of polypropylene fibers and the antistatic fibers made from polypropylene blends can also be improved by using carbon nanotubes.

The use of nanotechnology to develop conductive adhesives and conductive coatings, surface treatment of the fabric, or the addition of nano-metal powder during the spinning process to make the fibers conductive. For example, in the antistatic agent for polyester–Nano-doped tin dioxide (ATO) finishing agent, a reasonable stable dispersing agent is selected to make the particles mono-disperse, and the anti-static finishing agent is used to treat the polyester fabric, and the surface resistance of the fabric is The unprocessed >1012 Ω level is reduced to the order of <1010 Ω, washing 50 times, the antistatic effect is basically unchanged.

The conductive fibers with good performance include black conductive fibers with carbon black as conductive material and white conductive fibers with white powder materials such as nano SNO2, nano ZNO and nano TIO2 as conductive materials. The white-tone conductive fiber is mainly used for making protective clothing, overalls and decorative conductive materials. Its color is better than that of black conductive fibers, and its application range is wider.

Related Tags:Nano silver colloid  Silver nanoparticles dispersion

purple tungsten anode material

WO2.72’s purple finely divided crystalline powder, which is a purple tungsten oxide that can be used in negative electrode materials, which can help lithium-ion batteries achieve ultra-fast charging, so that high-power density battery devices can be constructed to achieve smaller and lighter Device.

Purple tungsten oxide has a very high chemical activity and enhances electron conductivity. The material has a small internal resistance and excellent Li ion diffusibility. In particular, it has excellent discharge characteristics in a low-temperature environment, and has a rate characteristic equal to or higher than that of a double-layer capacitor (EDLC) discharge even at -40 °C. Previously, the rate characteristics of Li ion secondary batteries and Li ion capacitors at low temperatures have been an unsolved problem.

A battery with a new material is characterized by a power density and an energy density that can be increased to two to three times that of a double layer capacitor. Energy density is also improved compared to lithium ion capacitors designed to increase the energy density of EDLC. In the field of capacitors, Li-ion secondary batteries are not suitable for high-output applications due to insufficient output power and development difficulties, and the development of such batteries will make it possible to use batteries in high-output power applications.

It is said that the new battery materials are very likely to be officially put into commercial use, which may further expand the demand for tungsten oxide. The application advantages of lithium batteries using new materials are quite obvious, ranging from automobiles, micro/mild hybrid trains, elevators, uninterruptible power supply UPS to high-current power supplies.

Related Tags:Colloidal Silver  Antibacterial nano silver dispersion

ATO nanopowder applied for anti-static fiber

Nano-inorganic powder modified fiber materials are gradually becoming an important development direction of fiber material modification. Compared with other types of anti-static fibers, nanoscale metal oxide anti-static fibers have many unique excellent properties, such as being unaffected by climate and use environment, and good stability; nanoscale metal oxides are not easy to get from fibers. Shedding, the distribution is relatively uniform; the fiber preparation process is simple; the fiber is used in a wide range, and it can be used in any occasion where anti-static is required. The new nano-scale transparent conductive powder is prepared for the transparency and excellent electrical conductivity of the product. It is favored by people. There are three main ways to use nano-ATO for anti-static treatment of chemical fiber:

 

1) Adding nano ATO powder directly during fiber spinning, the key is the compatibility of inorganic nano ATO with fiber material, and special dispersing aid needs to be added;

 

2) Adding nano ATO or its aqueous suspension during the dyeing process of raw materials (such as tops and polyester filaments) to complete the dyeing and functionalization in one step;

 

3) Adding a nano-sized ATO aqueous suspension to the dyeing or finishing process of the grey fabric.

 

Wang Dong and others of the State Key Laboratory of Fiber Modification of Donghua University used nano powder ATO powder as anti-static agent and polyethyleneimine (PEl) as dispersant to stably and uniformly disperse nano-ATO in deionized water. For the first time, the suspension was used as a preheating bath for the spinning process of polyacrylonitrile fibers to improve the anti-static property of PAN fibers. Due to the difference in concentration of nano-inorganic particles inside and outside the fiber and the presence of a large number of micropores inside the primary PAN fiber, the nano-ATO particles can diffuse, migrate into the fiber or adsorb to the surface layer of the fiber. When the PAN fiber is stretched, dried, and densified, The nano ATO can remain in the fiber and form a conductive channel for the partial contact of the nano ATO, imparting anti-static properties to the PAN fiber. The experimental results show that the volume resistivity of nano-ATO modified PAN fiber decreases by three orders of magnitude, has good anti-static properties, and basically maintains the original mechanical properties of the fiber. In addition, the National Ultrafine Powder Engineering Research Center is also conducting research on the application of nano-ATO in the preparation of anti-static fibers and other fields.

 

At present, the most important method to improve the electrostatic properties of polyester fabrics is to use an organic anti-static agent for anti-static finishing through a simple fabric finishing technique. However, since organic anti-static agents have a large dependence on environmental humidity and poor durability of anti-static effects, an anti-static agent having excellent and durable anti-static properties has been sought as a research and development hot spot. Wu Yue et al. Emi used nano ATO powder for anti-static treatment of polyester fabrics. The experimental results show that the surface resistance of polyester fabric treated with nano-ATO anti-static finishing agent is reduced from untreated >1012 Ω to <1010 Ω, washing 50 times. The anti-static effect is basically unchanged. Chen Xuexue et al. “The anti-static function of nano-scale ATO anti-static agent on polyester fabric was coated by coating method. The experimental results show that only when ATO particles are exposed on the surface of the film, it can exert anti-static performance; when ATO When the particles are partially immersed in the film and partially exposed in the form of the film surface, the anti-static property of the film is long. Ding Zhongfu et al. used nano-ATO powders with different cerium doping amount for the anti-static treatment of polyester knitted fabrics. Studies have shown that the doping amount of powder is one of the main factors affecting anti-static properties, and is doped at 4%-8% antimony. Within the range of the test, the more the doping amount, the better its anti-static property, but the color of the powder will also deepen, which will affect its use on light textiles.

 

Fiber functionalization is an important development trend of synthetic fibers. China is a large country in the production and consumption of chemical fiber. anti-static treatment of chemical fiber will be one of the important application markets for nano ATO powder.

Related Tags:Colloidal Silver  Antibacterial nano silver dispersion

Application of Nano Titanium Nitride in Electrochemistry

Nano titanium nitride can be dispersed in other materials to form a conductive network due to its small particle size and large specific surface area, which greatly improves the electrical conductivity of the composite. Therefore, nano titanium nitride is a material with broad application prospects. Among them, the application of nano titanium nitride TIN in electrochemistry is as follows:

1) Application in fuel cells

1 nano TiN as electrode catalyst carrier material

As a carrier material for the electrode of a fuel cell, nano titanium nitride TiN not only improves the electrooxidation ability of the anode to organic fuel such as methanol, but also improves the electroreduction catalytic performance of the cathode for oxygen, and synergistic effect with the platinum Pt. The corrosion resistance and long-term stability of the electrode are greatly enhanced, and the performance of the fuel cell is greatly improved.

Application of nano TiN in bipolar plate materials

The metal materials generally used as the plates include Ti, Al, and stainless steel, and the disadvantage of using the metal plates is that the corrosion resistance is relatively poor, which cannot meet the long-term stability of the fuel cell. TiN has high electrical conductivity, corrosion resistance, oxidation resistance and excellent mechanical properties. It is suitable for composite modification of metals such as Ti, Al and stainless steel to improve the corrosion resistance and electrical conductivity of bipolar plates.

2) Application in super-capacitors

Various nano structured TiN with excellent electronic conductivity and high specific surface area, such as nanotube arrays, nanowires, nanorods, and core-shell structures, can improve the capacitance performance and cycle stability of super-capacitors.

3) Application in lithium ion battery

As a carrier material for lithium-ion batteries, TiN not only improves the conductivity of the electrode, but also greatly increases the diffusion coefficient of lithium ions, thereby improving the capacity, rate and stability of the battery. It is widely displayed in lithium-ion batteries. Application prospects.

Silver nanowire “ink” makes paper-based printing electronic products possible

By suspending tiny metal nanoparticles in liquids, Duke scientists are developing conductive inks for inkjet printers that can print inexpensive, customizable circuit patterns on any surface virtually .

Printed electronics have been widely used on a number of devices, such as anti-theft radio frequency identification (RFID) tags that are usually found behind new DVDs. It currently has a major drawback: in order for the circuit to work, it must first be heated to fuse all of the nanoparticles into a single conductive filament, which makes it impossible to print circuits on cheap plastic or paper.

A new study by Duke University researchers shows that adjusting the shape of the nanoparticles in ink eliminates the need for heating.

By comparing the conductivity of thin films made from different shapes of silver nanostructures, the researchers found that electrons made of silver nanowires are much easier to fabricate than films made of other shapes such as nanospheres or microdisks. In fact, the flow of electrons through a film made of nanowires is so easy that they can be used in printed circuits without melting them together.

Benjamin Wiley, an assistant professor of chemistry at Duke University, said: “the conductivity of nanowires is 4000 times higher than that of commonly used silver nanoparticles that can be found on printed RFID tags. So if you use nanowires, then you don’t need to heat the printed circui to such a high temperature that you can use cheaper plastic or paper.”

Wiley added: “in addition to these silver nanowires, I really don’t think there is anything else that can be simply printed out like this. Without any post-processing, it can be directly conductive.”

Applications of these types of printed electronics may go far beyond smart packaging. Researchers envision using this technology to make solar cells, printed displays, LEDs, touch screens, amplifiers, batteries, and even some implanted bioelectronic devices.

Wiley said that silver has become a raw material for the manufacture of printed electronic materials, and many recent studies have shown the measurement of the electrical conductivity of silver nanostructure films of different shapes. However, experimental errors make it difficult to make direct comparisons between different shapes, and there are few reports that relate the conductivity of the film to the total mass of silver used, which is an important factor when using expensive materials.

“We want to eliminate any extra materials from ink, just focus on the silver content in the film and the link between the nanostructures as the only source of variation,” said Stewart, another graduate student.

Stewart uses known recipes to make silver nanostructures with different shapes, including nanoparticles, microchips, and short and long nanowires. These nanostructures are then mixed with distilled water to make a simple “ink.” He then invented a quick and easy way to make films using glass slides and double-sided adhesive tapes that can be easily found in any laboratory.

Stewart said: “We used punches to punch wells out of double-sided tape and stick it to the glass.” By adding a precise amount of ink to each well of the tape, the well was then heated to a temperature of The relatively low temperature at which the water evaporates or the relatively high temperature at which the structure begins to melt, he has obtained a variety of films for testing.

The research team said that they are not surprised that the long nanowire film has the highest conductivity. Electrons usually pass easily through a single nanostructure, but they tend to get stuck when they have to jump from one structure to the next, Wiley explained, while long nanowires greatly reduce the number of electronic “jumps.”

However, they were surprised by the intensity of this change. “The resistivity of long silver nanowire films is orders of magnitude lower than that of silver nanoparticles, and only ten times larger than pure silver,” Stewart said.

The team is now experimenting with aerosol inkjet printers to print silver nanowire inks in available circuits. Wiley said that they also want to explore whether silver-plated copper nanowires can produce the same effect, which is much cheaper than pure silver nanowires.

“King of whiskers” silicon carbide (SiC whisker) and its related toughened composites

With the rapid development of modern science and technology, the fields of aerospace, energy and other fields put forward higher requirements for the performance of structural materials. The development of new composite materials with high toughness, wear resistance, corrosion resistance and good thermal/chemical stability has become one of the hotspots in material research. Among them, whisker toughened composite materials have attracted much attention due to their excellent properties.

SiC whisker has the reputation of “king of whiskers” and has the advantages of high strength and high modulus of elasticity. The addition of silicon carbide whiskers has significantly improved the fracture toughness and flexural strength of composites. As an excellent reinforcing and toughening agent, SiC whisker toughened metal-based, ceramic-based and polymer-based composite materials have been widely used in machinery, chemical, defense, energy, environmental protection and other fields.

First, the nature of silicon carbide whiskers

SiC whisker (SiC whisker) is a highly oriented single crystal fiber with a diameter ranging from nanometer to micrometer. Its crystal structure is similar to that of diamond. There are few chemical impurities in the crystal, no grain boundaries, and few crystal structure defects. The phase composition is uniform. It has high melting point, low density, high strength, high modulus of elasticity, low thermal expansion rate, and wear resistance, corrosion resistance, and high temperature oxidation resistance. It is mainly used in toughening applications where high temperature and high strength applications are required.

The relevant indicators are shown in the following table:
Melting point: >2700 °C
Density: 3.21g/cm3
Tensile strength: 2100kg/cm2
Modulus of elasticity: 4.9×10^4kg/cm2

SiC whisker has two crystal forms of α type (hexagonal and rhombohedral structure) and β type (face-centered cubic structure), and the β type is superior to α type in all aspects. At present, only β-SiC whisker has achieved industrial scale production, so the research and use is mainly β-SiC whisker.

Second, the research and application of silicon carbide whiskers

At present, SiC whisker has been widely used to toughen metal-based, ceramic-based and polymer-based composite materials. The following is a brief introduction to the application of various fields.

1. SiC whisker toughened metal matrix composite
Under the premise of ensuring good wettability without serious interface damage and damage to whiskers, the current preparation process is more mature SiC whisker toughened aluminum matrix composites. Almost all commercial aluminum alloys can be successfully compounded with SiC whisker by die casting or powder metallurgy and have been put into practical use.

The main manufacturers of SiC whisker toughened metal matrix composite products are ACMC, Mitsubishi Electric, and US Naval Weapons Center. The products have the advantages of light weight, high strength, heat resistance, low thermal expansion coefficient and good degassing. It is used in aerospace and military fields, such as aircraft skins, airfoils, vertical tails, missiles, ultra-light space telescopes, etc. It can also be used in automobiles, machinery and other components and sports equipment.

2. SiC whisker toughened ceramic matrix composite
SiC whisker toughened ceramic materials are mainly Al2O3, ZrO2, mullite ceramics and the like. As the composite technology continues to mature, SiC whisker toughened composite materials such as Si3N4, ZrB2 and glass ceramics have emerged.

a. Al2O3 ceramic matrix composite
Alumina ceramics have the advantages of high melting point, high hardness, wear resistance and structural stability, but their strength is low. After toughening and strengthening by SiC whisker, the toughness can reach above 9MPa·m1/2, and the strength can reach 600-900Mpa.

The use of silicon carbide whiskers for further broaden the use of alumina has been applied to wear parts, cutting tools and certain components of internal combustion engines.
Among them, SiC whisker toughened ceramic cutting tool materials have excellent performance in difficulty of cutting alloys such as high-temperature alloys due to their good fracture toughness and thermal shock resistance, prolonging the service life of the tool, and the cutting efficiency is much higher than ordinary tools and have great application potential.

b. ZrO2 ceramic matrix composite
Zirconium oxide ceramics are widely used as refractories, fast ion conductors, high temperature heating elements, etc. due to their high chemical stability, high melting point, and good high temperature conductance. Due to the failure of the phase transformation toughening mechanism at high temperatures, its high temperature mechanical properties are seriously deteriorated. The addition of SiC whisker can increase its modulus of elasticity, hardness, high temperature strength and toughness, thereby expanding its application range.

At present, SiC whisker toughened ZrO2 ceramics can be applied to gas turbine rotors, turbine stator blades, various ceramic engine components, ceramic tools, wire drawing dies, bearings, etc. used above 1350 °C.

c. mullite ceramic matrix composite
Mullite ceramic has the advantages of uniform expansion, good thermal shock resistance, high hardness and low temperature creep value. It is a high-quality refractory material, but its toughness is relatively low, thus affecting its practical application.

Huang Zhengren from the Shanghai Institute of Ceramics of the Chinese Academy of Sciences used 30 vol% β-SiC whiskers to reinforce mullite. Under SPS sintering conditions, the material strength is about 10% higher than the hot pressure, 570 MPa, and the fracture toughness is 4.5 Mpam 1/2. Mullite increases by more than 100%

d. ZrB2 ceramic matrix composite
ZrB2 ceramics have the advantages of high melting point, high hardness, excellent wear resistance and chemical stability. They are typical ultra-high temperature ceramics and can be used in metallurgical industry, casting of electronic equipment and refractory metals. Due to the low toughness, it limits the further expansion of its application range. The addition of SiC whisker to the ZrB2 matrix improves the toughness of the material.

Studies have shown that when silicon carbide whiskers are added in a volume fraction of 30%, the toughness of the material can reach 6.33 MPa·m 1/2, which is 71% higher than that of pure ZrB2 ceramics, and 33% higher than that of SiC particles toughened ZrB2 ceramics. %. SiC whisker toughened ZrB2 ceramics can be used in thermal protection equipment, front compartments of supersonic aerospace vehicles, and heat-resistant components such as rocket nozzles.

e. SiC whisker toughened silicon nitride ceramics
SiC whisker toughening Si3N4 ceramics is one of the main ways to improve its fracture toughness and stability. Previous studies have shown that whisker toughening effect depends not only on the degree of whisker dispersion, whisker size and volume fraction, but also on the spatial position and orientation of whiskers.

Researchers have studied the whisker orientation in silicon nitride-based composites of SiC whiskers. When the whiskers are in the same direction and the whiskers are weakly connected to the substrate interface, the fracture toughness in this direction has a maximum value. The strength and fracture toughness were 1038 MPa and 10.7 MPa m 1/2, respectively.

A series of excellent physical and mechanical properties and chemical properties of silicon nitride ceramics have great market and application potential in high temperature structural materials, tool ceramic materials, wear resistant ceramic materials and wear resistant ceramic materials. With the deepening of whisker toughening research, the application of silicon nitride ceramics in tools, bearings, engines, insulation materials, etc. will be more perfect.

f. glass ceramic matrix composite
The addition of SiC whisker to the glass ceramic not only preserves the advantages of easy glass forming, but also increases the strength and toughness of the material by more than two times.

For example, SiC whisker toughened and reinforced bioactive glass-ceramic composites have a toughness of 4.3 MPa·m 1/2, a strength of up to 460 MPa, and a Weibull coefficient of up to 24.7, due to the non-toxicity of SiC whisker and the bioactivity of bioglass ceramics. The material has a life expectancy of more than 50 years under the stress equivalent to the flexural strength of the human body, and is the bio-ceramic material with the longest life expectancy. It can be used to prepare artificial teeth and bone repair materials and bones such as bones and joints. Tissue engineering scaffolding material.

3. SiC whisker toughened polymer composite
As a toughening and reinforcing agent for polymer materials, SiC whisker does not increase the melt viscosity, but also significantly improves the toughness and elongation of the material. It can be used to prepare parts with complex shapes, high precision and high surface finish.

Studies have shown that the addition of SiC whisker with a mass fraction of 5% in PVC can increase the toughness of the material by 50% and the elongation by more than four times. Therefore, SiC whisker is compounded with polymers such as PVC to produce composite materials with excellent properties, such as: jet engine oil tank blades, helicopter propellers, aircraft and automotive components.

Nano-tungsten oxide & titanium dioxide — new advanced nano transparent heat-insulating coating

Breif introduction:
Nano transparent thermal insulation coating is a ceramic thermal insulation water-based coating. It adopts the latest composite ceramic nano-tungsten oxide insulation material and is designed to absorb infrared infrared light. Nano transparent thermal insulation coatings are unique environmentally friendly ingredients – nano tungsten oxide liquid, titanium dioxide can remove odors in the surrounding environment, and degrade formaldehyde and other harmful substances. Nano-transparent thermal insulation coating is a new type of coating that meets the requirements and characteristics of environmentally friendly coatings.

Principle of heat insulation

The principle of thermal insulation of nano transparent thermal insulation coatings is as follows:
1 Nano transparent heat-insulating coating uses advanced production technology to make nano-tungsten oxide and TiO2 into nano-coating materials suitable for surface coating on glass, ceramic tile, metal, cement, PE, PET, PC, PP, PVC, etc. Transparent nano-tungsten oxide, which absorbs near-infrared rays and blocks ultraviolet rays;
2 Nano-tungsten oxide has stable chemical properties and small physical changes caused by external environment such as heat and humidity, so it can maintain permanent semiconductor materials, effectively block infrared radiation and ultraviolet radiation, block infrared effect by 95%, block UV The effect is up to 99%, the coating material has excellent compatibility with the substrate, the spreading and leveling performance is good, the adhesion is strong, and the long-lasting does not fall off;
3 Ceramic powder can effectively block ultraviolet light up to 99%, and can reflect more than 90% of visible light, can block infrared rays up to 92.5%, ceramic molecules can prevent excessive water vapor from entering, and allow normal amount of water molecules to pass, This greatly increases the sunscreen insulation capacity of the entire building surface;
4 Nano transparent heat-insulating coatings are safe and environmentally friendly. All components are nano-inorganic, which is a new type of environmentally friendly coating.

Characteristics:

The characteristics of nano-transparent thermal insulation coatings are as follows:

1 Thermal insulation
The nano transparent heat-insulating coating effectively blocks the infrared rays and ultraviolet rays in the sunlight from entering the room, shielding more than 99% of the ultraviolet rays, blocking the infrared rays of more than 75%, and lowering the indoor temperature by 3-5℃, so that the exposed objects can be dried. The temperature is lowered by 6-10℃.

2 transparent
After the nano transparent heat-insulating coating is applied, a micro-film layer of about 8-10 microns is formed on the surface layer of the substrate, and the visible light transmittance is as high as 70% or more, which does not affect the visual field.

3 energy saving
The effect of heat insulation and heat preservation of nano-transparent heat-insulating coatings extends the indoor and temperature-equal temperature rise and fall, reduces the number of air-conditioning cold or heat machines, and saves air-conditioning energy consumption by 25-35%.

4 Environmental protection
Nano-transparent heat-insulating coatings are water-based coatings that do not contain harmful substances such as TVOC, free formaldehyde, lead, chromium, cadmium, and mercury. They are environmentally friendly and meet the national environmental quality standards. They are a new type of environmentally friendly coating.

5 health
Nano-transparent heat-insulating coatings prevent UV rays from fading and aging of furniture, fabrics, carpets, curtains, murals, etc., and prevent UV-induced skin cancer, cataracts and other diseases.

Application range
1 The glass surface is insulated and resistant to ultraviolet rays;
2 External wall latex paint is insulated and antistatic;
3 PE, PET, PC, PP, PVC insulation, anti-static;
4 lamp cup, lampshade insulation, antistatic, etc.

Nano SiO2 is widely used in many aspects, and here are some applications of silica nanopowder in coatings.

1. Application of nano-silica SIO2 in architectural coatings
Adding nano-silica to architectural coatings can improve coating adhesion, scrub resistance, weather resistance, strength hardness, toughness, elasticity, anti-aging, anti-bacterial, anti-ultraviolet and other characteristics, significantly improve coatings’ property of self-cleaning, waterproofing, anti-seepage, anti-wear, anti-corrosion, color retention and other properties, so it has a good effect on modified exterior wall coatings.

2. Application of nano-silica in metal protective coatings
The addition of nano-SIO2 and TIO2 can increase the strength of the carbonaceous layer after the expansion of the fire retardant coating and prolong the fire resistance of the steel structure. When adding 1.5% by mass of nano-SIO2, the fire endurance of 110 min can be achieved.

3. Application of nano-silica in plastic coatings
The modified nano silica is beneficial to improve the thermal stability of the composite, delay the thermal oxidative degradation of the polyethylene, and significantly improve the flame retardant performance of the halogen-free flame retardant polyethylene. A material with better mechanical properties and flame retardancy.

4. Application of nano-silica in UV-curable coatings
Nano-silica has extremely strong UV absorption and infrared reflection properties. The spectrophotometer test shows that the absorption rate of ultraviolet light within a wavelength of 400 nm is as high as 70% or more, and the reflectance of infrared light within a wavelength of 400 nm is also more than 70%. It is added to the coating to form a shielding effect on the coating to achieve anti-UV aging and heat aging, and at the same time increase the thermal insulation of the coating.

5. Application of nano-silica in color inkjet paper coating
There are a large number of micropores and cracks on the surface of high gloss color inkjet paper. Primer can significantly improve sheet properties, and nanoscale silica provides high smoothness, absorbency, color density, and image quality.

6. Application of nano-silica in wood coatings
In the waterborne wood coating, the addition of the nano silica gel can improve the hardness of the coating film, improve the water resistance and aging resistance of the coating film, and at the same time improve the blocking resistance of the coating film. In the closed primer, the nano-silica gel has a small particle size and can be easily inserted into fine pores of wood or fiberboard. The pores are filled and sealed, and can be bonded to the substrate after drying and forming. Insoluble in water coating, which has a good sealing effect. A suitable nano-silica sol can be properly blended in the aqueous primer to accelerate the release of moisture in the primer.
It can improve the drying speed, increase the hardness of the coating film, and reduce the cost of the primer. Adding a certain nano-silica sol to the water-based topcoat has obvious improvement in water resistance, anti-blocking and hardness properties.