Organic modification of titanium dioxide and its effect on ABS engineering plastics
Due to the defects of titanium dioxide itself and the strong polarity on the surface, titanium dioxide without surface treatment is easy to absorb water and agglomerate during production, storage and transportation, which limits its application in organic polymers due to its easy agglomeration. Therefore, effective surface modification of titanium dioxide to improve its dispersibility in organic polymers and compatibility with the application system has become the key to the wide application of titanium dioxide. In order to improve the wetting, dispersion and rheological properties of titanium dioxide in various dispersion media, it is usually necessary to carry out organic modification.
The organic surface modification of titanium dioxide was carried out with different organic modifiers, and the effects of different organic modifiers on the surface hydrophilicity and hydrophobicity, Lab and oil absorption of titanium dioxide powder were studied, as well as the effects of different organic surface treatments on melt index, tensile strength, etc. The influence of material properties such as tensile strength and impact strength. The results showed that:
(1) The use of polysiloxane A, polysiloxane B, and polyol organic modifier to treat titanium dioxide has no significant effect on the Lab value of the powder, and the oil absorption index of the product is reduced;
(2) The titanium dioxide treated with polysiloxane exhibits hydrophobic properties, which enhances its compatibility with plastic resins;
(3) The titanium dioxide modified by polyols is hydrophilic, and it is easy to absorb water, which affects the application performance of plastics;
(4) In the ABS resin system, titanium dioxide treated with polysiloxane A is added, which has the least influence on the mechanical properties of plastic products, and the tensile properties and impact strength of the material are the best.
(5) It is recommended that the titanium dioxide used in the engineering plastics field be modified with polysiloxane modifiers, and organic modifiers containing different groups should be selected according to different application systems to improve the overall performance of the material.
Heavy calcium, light calcium, nano calcium, who is the favorite of PVC?
Calcium carbonate is widely used to fill polyvinyl chloride (PVC), polyethylene (PE) and other resins. Appropriate addition of calcium carbonate helps to improve the performance and processing performance of PVC products, such as improving the dimensional stability of products and improving product quality. Stiffness and hardness, improve the heat resistance of products, improve the printability of products, etc. Because the price of calcium carbonate itself is relatively low, only a comprehensive understanding of the properties of different types of calcium carbonate and the processing technology during use can better improve the cost performance of products.
1. Selection of calcium carbonate types
Heavy calcium is widely used in the foam layer of PVC calendered synthetic leather.
Light calcium is widely used in calendered leather surface layer, calendered hard sheet and calendered film. The light calcium used in calendering molding has a fine particle size and is easy to agglomerate, which is easy to cause white spots on the product, so the surface needs to be activated. The surface organic coating of calcium carbonate can make it hydrophobic, reduce agglomeration, increase the compatibility with PVC polymer, and improve its mechanical properties.
The particle size of nano-calcium carbonate is 1~100nm, which shows better performance than active calcium, and has a certain reinforcing effect.
2. The effect of calcium carbonate addition on the properties of calendered products
Calcium carbonate mainly plays a role in increasing capacity and reducing cost in PVC calendered products. With the increase of calcium carbonate filling ratio, the mechanical properties of calendered products gradually decrease. Among them, nano-calcium carbonate has little effect on the strength of PVC products. In the case of requirements on the mechanical properties of products, nano-calcium carbonate can be preferred.
3. The effect of calcium carbonate surface treatment on product performance
Calcium carbonate, especially light calcium carbonate and nano-calcium carbonate, have small particle size, large surface area, strong hydrophilicity, and easy secondary agglomeration, so their surface needs to be treated to obtain hydrophobic calcium carbonate.
Heavy calcium carbonate mainly has a filling and compatibilizing effect on PVC. It has poor compatibility with PVC and has a great impact on mechanical properties. It is recommended to be used in the foam layer of PVC calendered synthetic leather or in application scenarios where mechanical properties are not required. middle. For application scenarios that require high mechanical properties, it is better to use light calcium carbonate and nano-calcium carbonate. Light calcium carbonate or nano calcium carbonate.
4. The influence of the feeding sequence on the product
The feeding sequence of calcium carbonate is very important in the PVC processing process. Add PVC powder, calcium carbonate and stabilizer in sequence to the high-speed mixer, stir evenly at low speed, then turn to high-speed stirring until the temperature rises to 40~60°C, and add plasticizer and other liquids while stirring at high speed. Continue to stir to 100~120°C, the mixture is preferably in the form of flowable sand, and then put into an internal mixer for kneading and calendering to form a film.
5. Abnormal problems and improvement of calcium carbonate in the application of PVC calendering
The abnormal problems of calcium carbonate in the application of PVC calendering are mainly miscellaneous spots, white spots, drag lines, white folds, and decreased mechanical properties. Miscellaneous spots appear in calendered products, the reason is that calcium carbonate is mixed with impurities during production or transportation. You can observe the sieve residue during incoming inspection to see if there are variegated particles, and replace the qualified batch of calcium carbonate. The main cause of white spots and drag lines is the secondary agglomeration of calcium carbonate. The solution is to replace it with surface-treated calcium carbonate. The outer packaging of calcium carbonate should be protected from moisture to reduce the secondary agglomeration of calcium carbonate caused by moisture. For ultra-thin products with white spots, it is recommended to replace nano-scale calcium carbonate for production.
For the whitening or the decline of mechanical properties caused by the addition of excessive calcium carbonate, it is necessary to reduce the amount of calcium carbonate added, or replace it with light calcium carbonate or nano-scale calcium carbonate to improve the mechanical properties of the product.
Common 3 Types Of Flame Retardant Mineral Materials
Flame retardant mineral materials are flame retardants processed on the basis of natural minerals. According to their flame retardant mechanisms, they can be divided into ordinary minerals (hydroxides, carbonates, sulfates, etc.), clay minerals, and expandable minerals. Graphite etc.
1. Common mineral flame retardants
Metal hydroxides, carbonates, sulfates, etc. as flame retardants generally meet the following conditions: they can endothermic decomposition at a certain temperature (100-300 °C), and can release more than 25% of H2O or CO2 by mass fraction. and good filling performance; rich raw materials, low cost, low solubility and less harmful impurities. Such minerals can absorb the heat released by the combustion of the polymer and the radiant energy in the flame during the decomposition process, and the water vapor or (and) CO2 generated by the decomposition can dilute the concentration of the combustible gas and oxygen generated by the combustion of the polymer, reduce the surface of the material. The temperature can slow down the combustion speed and prevent the combustion from continuing; the metal oxide produced by the decomposition can be used as a covering layer to isolate the air and block the flame to prevent the flame from spreading. Compared with halogen-based and phosphorus-based flame retardants, it does not produce toxic and corrosive gases during the flame retardant process, and has obvious advantages in environmental protection, showing a vigorous development trend.
2. Nanoclay mineral flame retardant
Clay minerals are usually uniformly dispersed in polymers at the nanoscale, and the nanosheets of clay minerals act as a barrier to small molecules, combustible vapors and heat released from polymer combustion in two-dimensional directions, and degrade the polymer condensed phase. Combustion has a significant impact, and the clay platelets in the two-dimensional direction can also hinder the feedback of heat generated by gas-phase combustion to the condensed phase, thereby improving the flame retardant properties of the polymer. The nano-sized dispersed clay platelets have an obvious limiting effect on the mobility of polymer macromolecular chains, so that the macromolecular chains have a higher decomposition temperature than the completely free molecular chains when thermally decomposed.
3. Expandable graphite flame retardant
Expandable graphite (EG) is a special graphite intercalation compound formed by chemical treatment of natural flake graphite. Graphite has a layered structure, and alkali metals, strong oxidizing oxoacids, etc. can be embedded between the layers to form interlayer compounds, which begin to expand through the decomposition, gasification and expansion of the interlayer compounds at about 200 °C, and reach about 900 °C. The maximum value, the expansion range can reach 280 times, the expanded graphite changes from flake-like to low-density "worm" shape, which enhances the stability of the carbonized layer in the form of a cross-linked network, prevents the carbonized layer from falling off, and can be used on the surface of the material. The formation of a high-efficiency thermal insulation and oxygen barrier layer can block the transfer of heat to the surface of the material and the diffusion of small-molecule combustible gases generated by the decomposition of the material to the combustion area on the surface of the material, preventing further degradation of the polymer, thereby blocking the combustion chain. To the effect of efficient fire and flame retardant.
EG exists in a stable crystal form and has excellent weather resistance, corrosion resistance and durability. The carbon layer formed by expansion has good stability and can play a good skeleton role. As a new type of halogen-free physical intumescent flame retardant, EG has a very low heat release rate in fire, very little mass loss, and generates little smoke. It meets the requirements of environmental protection and can be used as a synergist for expansion systems. Synergists and flame retardants are used to prepare new intumescent flame retardant products with halogen-free, low smoke, low toxicity, better physical and chemical properties and fire resistance. EG will be widely used as a flame retardant.
Application fields and characteristics of mullite-based composites
Mullite is a binary solid solution compound composed of alumina and silicon oxide. It is the most stable compound in the Al2O3-SiO2 binary phase diagram. There are very few natural minerals. At present, aluminum-containing and silicon-containing raw materials are mostly synthesized at high temperature.
Mullite has many excellent physical properties, such as high fracture toughness, high temperature resistance, oxidation resistance, thermal shock resistance, creep resistance, low thermal conductivity, strong electrical insulation, and low dielectric coefficient. In addition, mullite also has high chemical stability, and has good corrosion resistance in alkaline fluxes and carbonated fluxes. Therefore, mullite can be used in a variety of composite materials, and has been widely researched and applied in the fields of chemical industry, energy, environment and so on.
1. Coating material
Because of its excellent stability and low thermal expansion coefficient, mullite is often used in coating materials to increase the thermal shock resistance and oxidation resistance of the material. Because mullite has good heat and corrosion resistance, the use of mullite in coatings can also enhance the high temperature corrosion resistance of the material.
2. Polymer materials
Adding mullite to polymer materials can significantly improve the properties of the materials. Feng et al. uniformly distributed acicular mullite whiskers into epoxy resin to prepare mullite whisker epoxy resin composite material, which can increase the flexural strength of epoxy resin from 4.2MPa to 47.6MPa, and the wear rate is also significant reduce. In addition, the addition of mullite can also improve the vulcanization characteristics and resilience of SBR.
3. Thermal storage materials
Phase change materials/ceramic matrix composite energy storage materials have become one of the important research directions of thermal energy storage materials. Mullite-based porous ceramic material is a good heat storage and energy storage matrix material due to its large heat capacity, good thermal shock resistance and high porosity.
Cordierite-mullite composite ceramics are one of the most promising thermal storage materials for next-generation solar thermal power systems. Wu et al. prepared a series of cordierite-mullite composite ceramic materials using different aluminum and silicon raw materials, which can be used as the matrix of thermal storage materials.
4. Wave-transmitting material
Mullite-based wave-transmitting ceramic materials have excellent thermal shock resistance, high-temperature mechanical properties, chemical stability and excellent mid-infrared wave-transmitting properties, and can be used as special high-temperature optical window materials, such as radomes and antenna windows for high-speed aircraft. Wait. Its wave transmittance is mainly affected by its microstructure, such as impurities, grain boundaries, pores, microcracks and surface roughness. The preparation process includes hot isostatic pressing, vacuum sintering, microwave sintering and spark plasma sintering.
Chromium-aluminum phosphate material is also an ideal wave-transmitting material, but its mechanical properties are poor, and its composite with mullite can improve its mechanical properties and thermal shock resistance. Zhou Pingsen et al. used multiphase composite ceramic technology to prepare mullite reinforced chromium aluminum phosphate high temperature wave-transmitting ceramics. The results show that with the increase of mullite content, the thermal shock resistance and mechanical properties of multiphase ceramics are improved. .
5. Thermal insulation materials
Mullite fiber-based porous material has the advantages of low density, low thermal conductivity and certain strength, and is an ideal thermal insulation material. Among them, mullite fiber mainly has two kinds of external introduction method and in situ synthesis method.
6. Ceramic membrane material
As a new type of separation medium, ceramic membrane has the advantages of high temperature and high pressure resistance, corrosion resistance, high separation efficiency, easy cleaning and regeneration, etc. It is widely used in environmental engineering, food, medicine, biotechnology and other separation processes. Due to its unique fibrous structure, mullite is often used to prepare ceramic separation membrane materials.
Electronic grade polysilicon: the "food" of the electronic information industry
With the vigorous development of the photovoltaic industry, the domestic polysilicon industry has reached the world's largest output in just over ten years, and the production cost has also reached the world's advanced level. High-purity polysilicon material is the basic raw material for the information industry and solar photovoltaic power generation industry, and many developed countries in the world regard it as a strategic material.
The purity requirements of electronic grade polysilicon are extremely high, and it is the purest substance that can be obtained by human industrialization.
Electronic grade polysilicon can be divided into electronic grade polysilicon for zone melting and electronic grade Czochralski polysilicon. The quality requirements of polysilicon for electronic grade zone melting are more stringent. The monocrystalline silicon produced by the zone melting method has low oxygen and carbon content, low carrier concentration and high resistivity. It is mainly used in the manufacture of IGBTs, high-voltage rectifiers, thyristors, and high-voltage transistors. and other high-voltage and high-power semiconductor devices. The monocrystalline silicon wafers produced by the Czochralski method are widely used in integrated circuit memories, microprocessors, mobile phone chips, low-voltage transistors, electronic devices and other electronic products. %above.
In addition, my country's electronic-grade polysilicon testing equipment still relies on imports. On the manufacturing side, my country has basically solved the localized substitution of related equipment and materials. However, the core testing equipment for polysilicon products is completely dependent on imports, such as low-temperature Fourier transform infrared spectrometer LT-FTIR, inductively coupled plasma mass spectrometer ICP-MS, etc., and the testing process requires extremely high levels of testing personnel.
Judging from the current international development of electronic-grade polysilicon production technology, the production processes mainly include silane method, gas-liquid deposition method, fluidized bed, and improved Siemens.
The production cost of silane method is high, and the silane used is explosive, flammable, and has poor safety. Even at room temperature, there will be a fire hazard. The gas-liquid deposition method was developed and controlled by Japan. In production, a tubular reactor is mainly used, and the operating temperature condition is controlled at 1500 °C to generate liquid silicon directly in the gas. Currently, it is still in the research and test stage. Not used for mass production. The fluidized bed process method is mainly to carry out comprehensive control of product impurities, so it cannot produce high-quality electronic-grade polysilicon.
Electronic grade polysilicon is the most basic strategic material in the electronic information industry, which is related to my country's national economy, society and national defense security. How to continuously and stably produce high-purity electronic-grade polysilicon to meet the needs of downstream enterprises for electronic-grade silicon materials is an important research topic faced by polysilicon enterprises. It is necessary to strictly control all processes in the whole process of polysilicon production, reduce various factors that may cause pollution to a minimum, and further implement lean and refined operations in the operation process, change bad habits, and improve management. Electronic grade polysilicon has a place in the market.
The formula for surface modification is actually not simple!
1. Why should powder surface modification be carried out?
Surface modification can make inorganic powder change from general filler to functional modifier, and the purpose of modification is to select the necessary premise of modification method:
In order to enhance the compatibility between inorganic powder and organic polymer and the dispersibility in organic matter, to improve the mechanical strength and comprehensive performance of the material, organic surface modification can be selected;
To obtain new mineral intercalation compounds, such as clay or graphite intercalation compounds, intercalation modification can be selected;
In order to replace silica and supplement the deficiencies of silica in some properties, the surface can be coated with silica;
To replace titanium dioxide or reduce the amount of titanium dioxide, the surface can be coated with titanium dioxide;
In order to improve some special properties of rubber products, metal particles can be selected on the surface;
In order to improve the optical efficiency and visual effect of the product, metal oxides such as titanium oxide, chromium oxide and iron oxide can be selected on the surface.
2. How to choose a surface modifier?
The selection of surface modifier is the key to achieve the expected purpose of powder surface modification, and it has strong pertinence.
From the point of view of the interaction between the surface modifier molecules and the surface of the inorganic powder, the surface modifier that can chemically react or chemically adsorb with the surface of the powder particles should be selected as much as possible, because the physical adsorption is strong in the subsequent application process. Easy to desorb under stirring or squeezing, for example:
Inorganic powders (fillers or pigments) used for various plastics, rubbers, adhesives, oil-based or solvent-based coatings require good surface lipophilicity, that is, good affinity or compatibility with organic polymer binders, which It is required to select a surface modifier that can make the surface of inorganic powder hydrophobic and lipophilic;
The surface functional groups and reactive sites of calcined kaolin are mainly Si-O and Al-O bonds, so surface modifiers that are easy to form chemical coordination with Si-O and Al-O bonds should be selected;
For acidic minerals such as quartz powder, clay, wollastonite, and diaspore that contain more silicic acid, it is better to use silane coupling agent.
Titanate and aluminate coupling agents have chemical adsorption with basic minerals such as calcium carbonate under certain conditions and to a certain extent.
3. How to choose the surface modification process?
The surface modification process must meet the application requirements or application conditions of the surface modifier, have good dispersibility of the surface modifier, and can achieve uniform and firm coating of the surface modifier on the surface of the powder; at the same time, it requires a simple process and parameters. Good controllability, stable product quality, low energy consumption and low pollution.
Therefore, when selecting a surface modification process, at least the following factors should be considered:
Characteristics of the surface modifier, such as water solubility, hydrolyzability, boiling point or decomposition temperature;
Whether the front-end pulverization or powder preparation is wet or dry;
Modified process conditions, such as reaction temperature and reaction time.
4. How to choose surface modification equipment?
There are many types of powder surface modification equipment, including dry modification equipment and wet modification equipment. The selection is based on the surface modification method and process. The selection principles are as follows:
Good dispersibility for powders and surface modifiers. Only with good dispersibility can the powder and the surface modifier have a more equal opportunity and effect, and the amount of the surface modifier can be reduced.
The modification temperature and residence time can be adjusted within a certain range.
Low energy consumption and low wear per unit product. In addition to modifiers, the main cost of surface modification is energy consumption. Modification equipment with low energy consumption can reduce production costs and improve product competitiveness; low abrasion can not only avoid the pollution of modified materials, but also improve the operation of equipment. efficiency and lower operating costs.
In short, the purpose, method, process, equipment and other aspects of surface modification affect each other. It is necessary to consider comprehensively, take into account both left and right, and continue to explore in the correct thinking and direction, in order to find the most suitable surface modification technology for oneself.
Influence of talc purity on plastic modification effect
Plastic reinforcement modification is an important application field of talc, especially for polypropylene modification in the automotive and home appliance industries. Talc can increase the heat distortion temperature of products, increase dimensional stability, and reduce molding shrinkage. Ultrafine talc improves the rigidity, creep resistance, and impact strength of products. Therefore, many of the interior parts, exterior parts and structural parts of vehicles use talc-reinforced modified polypropylene materials.
Purity refers to the talc content of the product. The higher the purity of talc, the better its reinforcing effect. The direct measurement of talc purity is more complicated and can be estimated by the loss on ignition at 1050 °C, which is generally expressed by SiO2. The lower the loss on ignition, the higher the SiO2 value and the higher the purity. The SiO2 content of pure talc is 63.47%, and the loss on ignition is 4.75%. The enhancement and modification effect of talc powder with loss on ignition <8.5% is obvious; the enhancement effect of modification with loss on ignition is 8.5% to 16% is weak;
Natural talc contains impurity minerals, which will have various adverse effects on the modification effect. These impurities include: magnesite, dolomite, chlorite, quartz, iron salts, heavy metals, etc.
Studies have shown that the types and contents of talc impurities in different origins are different, and their effects on reinforcement and modification are also different. Magnesite and dolomite have obvious adverse effects on flexural modulus and thermal stability, and chlorite also has The adverse effects are smaller than those of magnesite and dolomite; heavy metals and iron salts have adverse effects on the anti-aging and thermal stability of plastics; the effects of heavy metals need to be treated differently, and the heavy metals in the talc structure are higher than those in carbon. Heavy metals in acid salts and other impurity mineral structures have less effect.
Therefore, when choosing a type of talc, not only should pay attention to its purity, but also understand the source of origin and the type and content of impurities in it.
5G commercial upgrade, CCL functional fillers usher in new opportunities
As the main material for processing and manufacturing printed circuit boards (PCBs), CCL can be used in the production of high-speed transmission equipment such as servers and memories, as well as components such as antennas, power amplifiers, and radars. It is widely used in televisions, radios, computers, computers, Mobile communications and other electronic products.
In 5G base stations, the circuit boards processed and manufactured by CCL are mainly used to produce communication equipment such as communication base station antennas and power amplifiers, which are installed in the communication network. Due to the substantial increase in communication frequency and transmission rate brought about by the upgrade of 5G communication technology, traditional CCL cannot meet the production requirements, and high-frequency and high-speed CCL has become the current main development trend of CCL.
According to the data, functional fillers are the main bearers of mechanical strength in substrate composites, so they are usually regarded as one of the most important research directions in the upgrading of copper clad laminate technology. The rapidly expanding and upgrading market also puts forward higher requirements for the supply of upstream materials in related industries. The domestic high-frequency and high-speed circuit board packing and mobile phone HDI board packing industries are expected to benefit from this industrial upgrading wave and achieve rapid development.
In order to meet the needs of high-frequency and high-speed data transmission, high-performance circuit substrates have become a necessary choice for making high-frequency and high-speed copper clad laminates. At present, with excellent dielectric constant and low dielectric loss performance, silica material is filled in polytetrafluoroethylene (PTFE) substrate as a reinforcing material, which has become the most important technical route for high-frequency and high-speed copper clad laminates. After adding silica functional filler, the dielectric properties and signal transmission quality of high-frequency and high-speed copper clad laminates can be improved to meet the quality requirements of 5G communication. At the same time, the silica functional filler also effectively improves the heat resistance and reliability of the circuit board.
In the current global high-end silica functional filler market, Japanese and American manufacturers still occupy a major position. However, with the further upgrading of my country's 5G market, the copper clad laminate industry will gradually concentrate in China, and my country has also achieved large-scale production of spherical silicon micropowder, gradually forming a domestic alternative.
The high-end electronics industry is developing rapidly, and the market demand for spherical silica powder is large
Spherical silica powder is made of selected angular silica powder as raw material and processed into spherical silica powder material by flame method. It has good fluidity, low stress, small specific surface area and high bulk density. It can be obtained as a filler. Higher filling rate and uniformity are widely used in high-end PCB boards, epoxy molding compounds for large-scale integrated circuits, high-end coatings, special ceramics, etc. The price is 3-5 times that of angular silicon powder.
Silicon micropowder is one of the core basic raw materials of the electronics industry, and the expansion of the advanced packaging market has driven the growth of the demand for spherical powder. According to Yole data, with the upgrading of the electronics industry, the scale of the advanced packaging market has gradually expanded. It is expected to occupy nearly 50% of the packaging market share in 2024, which is expected to further drive the growth of spherical silicon micropowder demand.
With the vigorous development of high-end electronic industries such as 5G intelligence, high-performance copper clad laminates and chip packaging industries are expected to drive the incremental market for silicon micropowder fillers. According to Absolute reports, the global sales of spherical silica for fillers will reach 159,000 tons in 2023, and its market size will reach US$660 million in 2024, with CARG5 reaching 9.2%. The output of spherical silica in the same year is estimated to be 184,900 tons, and the overall production and sales continued to grow. According to the data of the global copper clad laminate and chip packaging industry calculated by Guotai Junan Securities Research Institute, the total global demand for spherical silicon micropowder is expected to increase from 225,800 tons in 2020 to 396,200 tons in 2025, with an average compound growth rate of 11.90 tons from 2020 to 2025. %.
There is a broad prospect for automobile intelligence. The demand for printed circuit boards (PCB) for a single new energy vehicle is more than 5 times that of ordinary vehicles. According to industry chain research and other data, it is estimated that the demand for spherical silicon powder for new energy vehicles will reach 28,231.6 tons, of which the new energy vehicle copper clad laminate and the spherical silicon micro-powder for chip packaging increased to 15,880.3/12,351.3 tons respectively.
The general trend of the Metaverse is driving the development and upgrading of computing power. On the one hand, the growth of servers has expanded the demand for PCBs; on the other hand, high-speed, large-capacity, and high-performance servers will continue to develop, creating a large demand for high-level, high-density, and high-speed PCB products. According to industry chain research and other data, it is estimated that the demand for spherical silicon powder for servers will reach 18,542.1 tons in 2025, of which the filling volume of spherical silicon powder for copper clad laminates and chip packaging will increase to 10,429.9/8,112.2 tons in 2025, respectively.
The demand for high-performance PCB drives the expansion of the spherical microsilica market. The short-wave and high-frequency characteristics of 5G communication technology have higher requirements on the transmission speed, transmission loss, heat dissipation and other performance of the PCB, and the investment in routers, switches, IDCs and other equipment required to carry larger bandwidth traffic has increased accordingly. High-frequency and high-speed copper clad laminates need to use low-dielectric, low-loss fused silicon micropowder and spherical silicon micropowder as key functional fillers, and require low powder impurity content and high filling rate. Therefore, the demand for high-performance spherical silicon micropowder is gradually expanding. According to industry chain research and other data, it is expected that the total filling volume of spherical silicon micropowder for 5G base stations will increase to 1,295.8 tons in 2022.
Main application fields and characteristics of inorganic salt whiskers
Due to their high aspect ratio, high strength and tensile properties, inorganic salt whiskers can often be used as an important reinforcing material to be added to flame retardant materials, building materials, composite materials and friction materials. The action mechanism of whiskers in composites is mainly reflected in four aspects: load transfer, crack bridging, crack deflection and pull-out effect. Due to the high strength and high modulus of inorganic salt whiskers, when added to the composite material, it can play a certain role in strengthening and toughening the composite material.
1. Flame retardant materials
Research on the fire performance of new building materials is an important part of public protection and a necessary condition for large-scale application in construction projects. Due to its excellent high temperature resistance, inorganic salt whiskers are often added to other materials as flame retardant materials to improve the flame retardant properties of composite materials.
2. Building materials
At present, in the material consumption industry, the construction industry is one of the largest material consumption industries, accounting for about 24% of the global material consumption. In building materials, inorganic whiskers are widely used in building materials due to their certain aspect ratio and their excellent physical and chemical properties. Inorganic whiskers have crack resistance and filling effects at the microscale, so doping the whiskers into the composite material can effectively improve the comprehensive performance of the composite material.
3. Composite materials
Inorganic whiskers, as fillers, can enhance the physical and mechanical properties of composites to a certain extent. At the same time, the study pointed out that proper modification of whiskers can improve the comprehensive properties of composites.
4. Friction material
In recent years, whiskers as functional fillers have a certain enhancement effect on the improvement of automobile braking friction performance. RAJ et al. explored the effect of calcium sulfate whiskers as functional fillers on the friction performance of automobile brakes. By changing the content of calcium sulfate whiskers, according to the JASOC406 standard, a tribological study was carried out on an inertial brake dynamometer. The results showed that the mechanical properties of the material with the addition of 10% calcium sulfate whiskers were improved, and the friction was improved at the same time. performance, friction materials containing calcium sulfate whiskers wear less.