High performance fiber refers to the chemical fiber with special physical and chemical structure, performance and function, which usually has high tensile strength and Young's modulus, and has excellent properties of high temperature resistance, radiation resistance, acid and alkali resistance, fire resistance, etc. common varieties include carbon fiber, aramid fiber, ultra high molecular weight polyethylene fiber, basalt fiber, polyphenylene sulfide fiber, etc. High performance fiber composite is a kind of composite material processed with high performance fiber as reinforcement material and resin as matrix. It has the characteristics of light weight, high strength, high modulus, fatigue resistance, corrosion resistance, easy processing and forming. It is widely used in aerospace, national defense, rail transit, energy industry and other fields. It plays an important role in both military and civil fields It has a profound impact on national security, social economy, science and technology and human life. Therefore, as a representative and most widely used branch of advanced fiber composite, high-performance fiber composite has become an indispensable key material for the development of high-tech, National Defense advanced weapons and other strategic industries in the world.
At present, the global high-performance fiber and composite companies are mainly concentrated in Japan, the United States and Europe. Japan has three major carbon fiber and composite material suppliers: Toray, Dili and Mitsubishi Chemical, which not only accounts for half of the global carbon fiber production capacity, but also monopolizes the production technology of carbon fiber products in the high-end field. DuPont of the United States occupies a leading position in the aramid market. Compared with other enterprises, both the technical level of high-end products and the price level of low-end products are unique For advantages, Europe plays an important role in the field of UHMWPE fiber. DSM is the supplier of UHMWPE fiber with the highest output and the best quality in the world. China has initially realized the industrial production of a variety of high-performance fibers and composite materials, and has a certain industrial scale, but in high strength, high modulus and high-end There is still a big gap between the developed countries and the high-performance fibers used in the field in terms of key technologies of industrialization and product stability.
High performance fiber is an important basic material for the development of national defense, military industry, aerospace and other high-tech industries. In recent years, with the continuous decline in the price of high-performance fiber and the promotion of national energy conservation and environmental protection policies, the application scope of high-performance fiber in the civil field is expanding day by day, and the demand for high-performance fiber in some emerging industries such as wind power generation, automobile, high-speed rail, etc. is growing day by day, becoming a new economic growth point. Nowadays, the global high-performance fibers and composites are developing in the direction of advanced manufacturing technology, low-cost, high-performance materials, multi-functional and application expansion. In 2019, many countries in the world have made great achievements in cutting-edge technology exploration and application potential development in the field of high-performance fiber and composite materials.
1 the United States
The United States is the first country to carry out research on carbon fiber and aramid fiber, with the world's leading industrial chain of high-performance fiber, composite materials and composite products in various fields. At present, the United States has unique advantages in the application of high-performance fibers in aerospace and military industries, and the market for pressure vessels, wind power and automobiles is also developing rapidly. Carbon fiber occupies the largest market share of high-performance fiber materials in the United States, mainly used in the field of national defense and security. In recent years, UHMWPE fiber has become a new favorite of the US defense research department.
UHMWPE fiber has the lowest density and the highest strength among the developed fibers. It is the best bulletproof fiber at present and plays an irreplaceable role in the field of national defense and military industry. In September 2019, the U.S. Army Research Laboratory said it was preparing a new material for bullet proof clothing by a new technology combining UHMWPE with silica nanoparticles. This new material has higher strength and is an ideal material for absorbing bullet and other shell impact. In November 2019, U.S. officials said that at present, the U.S. special forces are testing a light combat armor, which is one of the achievements of the previous "Talos" (Figure 1). This light armor is a kind of "light polyethylene body protective armor", which is both strong and light, 25% lighter than the current standard protective equipment. This new type of combat armor Compared with the current standard infantry bulletproof clothing (body coverage rate 19%), the body coverage rate of armor is more than 44%, which can effectively protect the shoulder, front side, forearm and span of soldiers.
Figure 1 Tactical Assault light action suit
After nearly 40 years of development in the field of aerospace in the United States, high-performance fiber materials have entered a mature application period. The U.S. has rich experience in design and manufacturing in this field, and has successfully developed all carbon fiber / epoxy composite fuselage and other composite structural parts. The quality of carbon fiber composite in Boeing 747 has reached 50%. In the future, the main development direction of high-performance fiber and composite materials used in aerospace field is the research and development of structured and functional materials, as well as the development and application of low-cost and integrated technology. On March 15, 2019, AFRL, together with the University of Arkansas and the University of Miami, developed a 3D carbon fiber / epoxy composite material and a customized direct ink-jet 3D printing device (Figure 2), which can be used to process short fiber epoxy composite structures in the aerospace field. The development of this material is the next generation of multi-functional UAV The manufacturing of structural parts provides technical support. In addition to the key areas of aerospace and military industry, the United States also attaches great importance to the application of high-performance fibers and composites in other fields.
Figure 2 3D carbon fiber / epoxy composite
On October 29, 2019, oceangate announced that it plans to use carbon fiber and titanium to design and build two new submersibles to meet the growing expedition, research and commercial demand for deep-sea manned submersibles. In the field of automobile, General Motors announced in 2019 that it will start GMC Sierra Denali 1500 (Figure 3) and GMC Sierra at4 Carbon fiber carriage is used in 1500 ", which is jointly developed by general motors and Dili. It is the first time in the world that carbon fiber reinforced thermoplastic is used in mass production of automobile structural parts. Compared with other pickup carriages, the weight of this" carbonpro "is reduced by about 25%, and it has first-class dent resistance, scratch resistance and corrosion resistance.
Figure 3 GMC Sierra Denali 1500
While promoting the market-oriented application of high-performance fiber and composite materials, American researchers have been committed to the research of new structures and new functional materials. In June 2019, Ajayan team of Rice University in the United States developed a kind of laminated composite material with high dielectric, high thermal conductivity and high temperature resistant aromatic polyamide fiber reinforcement. The dielectric constant of the material is up to 6.3, the thermal conductivity is up to 2.4W · M-1 · k-1, the breakdown strength is up to 292mv · m -, and the young's modulus is up to 11gpa, which is expected to be used in high temperature energy storage devices.
As a reinforced material of composite, the mechanical properties of high-performance fiber affect the properties of fiber composite to a great extent. Therefore, Georgia Institute of technology in the United States has conducted in-depth research on the preparation of high-performance carbon fiber. Its research team has developed a new technology, which can improve the strength and modulus of carbon fiber. In January 2019, Kumar team of Georgia Institute of technology successfully prepared nano microcrystalline cellulose (CNC) carbon fiber with mass fraction more than 40% using PAN fiber as raw material. The tensile strength of PAN / CNC based carbon fiber is in the range of 1.8-2.3gpa, and the tensile modulus is in the range of 220-265gpa.
2 Japan
Japan has a strong global competitiveness in the category, production technology, product quality and series development of high-performance fiber and composite industry, and is the country with the most complete category of high-performance fiber products. Especially in the field of carbon fiber, Japan has the most technology patents in the world, covering all aspects of the industrial chain, and occupies more than 70% of the global market share of PAN based carbon fiber, occupying a dominant position in the international market. In order to maintain its leading position in the high-performance fiber and composite industry, Japan has a research layout for key materials in all links of the industrial chain.
Japanese enterprises attach great importance to the research and development of high-performance fiber and composite technology. They have a large number of research and development personnel from the production process to the application of composite materials. On November 18, 2019, through its own polymer technology and fiber technology, Dongli company developed the world's first porous carbon fiber with nano scale continuous pore structure (Figure 4), and can use its own technology to ensure the uniform distribution of pores and customize the fixed size of the porous structure. This fiber material has a tight structure and light weight, excellent chemical stability and permeability Gas property can be used to make the support layer of advanced membrane materials, to achieve more environmentally friendly natural gas and biogas purification, greenhouse gas separation and safe hydrogen production.
Fig. 4 structure diagram of porous carbon fiber with nanometer continuous pore structure
In 2019, Japan's leading carbon fiber supplier made advanced research results in the development of new fiber prepreg. On March 4, 2019, the company announced that it has developed a new type of carbon fiber reinforced BMI prepreg, which has a glass transition temperature of up to 280 ℃, a high compressive strength after impact and a small linear thermal expansion coefficient. It is the first BMI prepreg with high heat resistance and high impact resistance in Japan, which is zero for aerospace engines The production of components provides a new idea.
Dongli company has successfully developed a new air carbon fiber reinforced plastic (CFRP) prepreg and a new prepreg system "Dongli tc346" for high-end automobiles and racing cars. Among them, the new type of CFRP prepreg is suitable for vacuum forming technology. Compared with the traditional prepreg using autoclave forming technology, it can significantly reduce the manufacturing cost. "Toray tc346" has excellent mechanical properties and surface gloss. It is the product with the highest performance at present. It can be made into unidirectional tape or fabric of various weights and fibers, and widely used in racing gearbox, suspension, wing and anti-collision structure.
As the world's first mass production enterprise of carbon fiber for automobile, Japanese Imperial company has been accelerating its research in this field for many years. On March 6, 2019, the company developed a multi material composite door concept, which is made of carbon fiber sheet molding compound (SMC), glass fiber SMC and unidirectional glass fiber reinforced plastic (GFRP), with high strength, low weight, excellent heat resistance and shock absorption, excellent design freedom and energy It can realize deep drawing and other advantages. The company plans to launch commercial door modules in 2025 and strive to become a global supplier of multi-material auto parts.
Figure 5 prototype of side door module of multi material composite vehicle
Japan has also carried out in-depth research on large-scale renovation of existing buildings and materials for roof expansion / renovation. On October 9, 2019, Taisei, Japan, developed a super light carbon fiber composite (CFRP) structural component - t-cfrp beam (Figure 6). The weight of the t-cfrp beam is only 1 / 5 of that of the steel frame, and the rigidity, strength and shape of the member can be designed freely according to the application of the building. The development of this technology will continue