[1] FRP scientific name glass fiber reinforced plastic. It is a composite material with glass fiber and its products (glass cloth, tape, felt, yarn, etc.) as the reinforcing material and synthetic resin as the matrix material. The concept of composite material refers to a material can not meet the requirements of use, the need for two or more materials composite together, composed of another material that can meet the requirements of people, that is, composite materials. For example, a single glass fiber, although the strength is very high, but the fibers are loose, can only withstand tension, can not withstand bending, shear and compressive stress, but also not easy to make a fixed geometric shape, is floppy. If they are bonded together with synthetic resin, can be made into a variety of hard products with a fixed shape, can withstand both tensile stress, but also can withstand bending, compression and shear stress. This constitutes a glass fiber reinforced plastic matrix composite material. Because of its strength is equivalent to steel, but also contains glass components, also has the color, shape, corrosion resistance, electrical insulation, heat insulation and other properties like glass, like glass, the history of the formation of this easy to understand the name "FRP", this term is the former Minister of the State Ministry of Building Materials Industry, Comrade Lai Interfa proposed in 1958! This term was proposed by Comrade Lai Jifa, the former Minister of the State Building Materials Industry in 1958, and was expanded to the whole country by the building materials system, and now it is still commonly used. It can be seen that the meaning of FRP is to refer to the glass fiber as reinforcing materials, synthetic resins as binder reinforced plastics, foreign countries called glass fiber reinforced plastics. With the development of China's FRP business, as a plastic-based reinforcing materials, has been expanded from glass fibers to carbon fibers, boron fibers, aramid fibers, alumina fibers and silicon carbide fibers, etc., undoubtedly, these new types of fibers made of reinforced plastics, is a number of high-performance fiber-reinforced composite materials, and then the common name of the glass fiber reinforced plastic can not be summarized. Considering the historical origin and development, usually use FRP composites, so that a name is more comprehensive.
[edit]Physical and chemical properties
Glass has a hard and fragile, with good transparency and high temperature, corrosion resistance and other properties; at the same time, the steel is very hard and not easy to break, but also has the characteristics of high temperature resistance. So people began to think, if you can make a kind of both the hardness of glass, high temperature, corrosion-resistant properties, but also has the characteristics of steel as hard and unbreakable, then this material will be of great use. People after research and testing, finally produced such a composite material. It is able to stand shoulder to shoulder with steel fiberglass. Let's look at a test, to understand its excellent performance or not. In a group of mountains surrounded by trees in the valley, a test is underway. People behind bunkers two hundred meters away have their eyes fixed on an oxygen cylinder placed in the center of the valley. The air compressor rotated rhythmically, filling that oxygen cylinder continuously through an alloy steel pipe. The needle on the pressure gauge tugged at everyone's heart. The reading rose gradually from 100-200-400-500 until it reached 700 kilograms per square centimeter, when there was a loud bang and the cylinder exploded! People around us cheered and jumped up, "It worked!" An oxygen cylinder is a high-pressure resistant container. The working pressure it is subjected to is 150 kg/cm2. In order to be safe to use, it is manufactured to endure three times the working pressure, i.e. 450 kg/cm2. It is qualified only if it does not burst. The oxygen cylinder tested above far exceeded the design requirements. What kind of steel is it made of? Is fiberglass reinforced plastic, more precisely, is made of glass and plastic composite together. Glass is a hard and brittle material, a drop on the broken, which has the name of the glass fiberglass can withstand the fall? So a new test. Another fiberglass oxygen cylinder was inflated to 150 kg/cm2 and rolled down the valley from the top of a mountain. It collided with jagged rocks and rolled all the way to the bottom of the valley still without bursting. The fiberglass oxygen cylinder went through a quality certification test. The tensile strength of normal glass is only one-eighth that of normal steel. The glass is melted, pulled into only one tenth of the diameter of the hair so fine glass fibers, the original hard and fragile glass into a soft and pull-resistant glass fibers, its tensile strength can be increased by more than ten times. As we all know, cement block pressure, steel tensile. With steel as the sinews, cement gravel as muscle, so that they are condensed into one, complement each other's strengths and weaknesses, and become strong - this is reinforced concrete. Similarly, such as we use fiberglass as the sinews, with synthetic resins (phenolic plastics, epoxy resins and polyester resins) as the muscle, so that they are condensed into one, made of materials, its tensile strength can be comparable to steel - therefore named FRP.
[edit]Advantages and disadvantages
Lightweight and high strength
Relative density between 1.5~2.0, only carbon steel 1/4~1/5, but the tensile strength is close to, or even more than, carbon steel, and the specific strength can be compared with that of high-grade alloy steel. Therefore, it has excellent results in aviation, rockets, spacecraft, high-pressure containers, and in other applications where weight reduction is required. Certain epoxy FRPs are capable of tensile, flexural and compressive strengths of over 400 MPa. The density, strength and specific strength of some of the materials are shown in Table 1-1.
Good corrosion resistance
FRP is a good corrosion-resistant material with good resistance to the atmosphere, water, and general concentrations of acids, alkalis, salts, and a variety of oils and solvents. It has been applied to all aspects of chemical anti-corrosion, and is replacing carbon steel, stainless steel, wood, non-ferrous metals and so on.
Good electrical properties
It is an excellent insulating material, used to make insulators. High frequency can still protect the good dielectric properties. Microwave permeability is good, has been widely used in radomes.
Good thermal performance
FRP thermal conductivity is low, room temperature 1.25 ~ 1.67kJ / (m-h-K), only 1/100 ~ 1/1000 of the metal, is an excellent thermal insulation material. In the case of transient ultra-high temperature, it is an ideal thermal protection and ablation-resistant material, which can protect the cosmic vehicle to withstand the high-speed airflow above 2000℃.
Good designability
①All kinds of structural products can be flexibly designed according to the needs to meet the requirements of the use, which can make the products have a good integrity. ② can fully select the material to meet the performance of the product, such as: can be designed to resist corrosion, resistance to transient high temperature, the product has a particular direction of high strength, good dielectric properties, and so on.
Excellent craftsmanship
① can be based on the shape of the product, the technical requirements, the use and the number of flexible choice of molding process. ② process is simple, can be molded in one go, the economic effect is outstanding, especially for complex shapes, not easy to form a small number of products, more prominent in its superiority of the process.
[edit]Insufficient
Low modulus of elasticity
FRP's modulus of elasticity than the wood twice as large, but 10 times smaller than steel (E = 2.1 × 106), so in the structure of the product is often feel the lack of rigidity, easy to deform. Can be made into a thin shell structure, sandwich structure, but also through the high modulus fiber or do reinforcement and other forms to make up.
Long-term temperature resistance is poor
General FRP can not be used at high temperatures for a long time, general-purpose polyester FRP at 50 ℃ above the strength of a significant decline, generally only in the use of the following 100 ℃; general-purpose epoxy FRP at 60 ℃ above the strength of a significant decline. However, you can choose high temperature resistant resin, so that the long-term working temperature of 200 ~ 300 ℃ is possible.
Aging phenomenon
Aging phenomenon is the same defect of plastics ****, FRP is no exception, in the ultraviolet ray, wind, sand, rain and snow, chemical media, mechanical stress and other effects can easily lead to performance degradation.
Low interlayer shear strength
The interlayer shear strength is borne by the resin, so it is very low. Interlayer bonding can be improved by selecting processes, using coupling agents, etc. The main thing is to try to avoid subjecting the interlayer to shear when designing the product.
[edit]FRP production methods
Basically, there are two main categories, namely, wet contact type and dry pressurized molding. Such as by process characteristics, there are hand-layup molding, laminated molding, RTM method, extrusion and pulling method, molding, winding molding and so on. Hand-paste molding also includes hand-paste method, bag pressure method, spraying method, wet paste low-pressure method and moldless hand-paste method. Currently the world's most used molding methods are the following four. ① hand paste method: mainly used in Norway, Japan, Britain, Denmark and other countries. ② Jet method: mainly used in Sweden, the United States, Norway and other countries. ③ Molding method: Germany is the main country. ④ RTM method (resin transfer molding): mainly used in Europe and the United States, Japan. There are also: fiber winding molding method, pultrusion molding method and hot compression molding method, etc. China has more than 90% of FRP products are produced by hand-laying method, the other molding method, winding method, laminating method, etc. (see Chapter XI). In Japan, the hand-lay-up method still accounts for 50%. From the viewpoint of countries around the world, the hand-laying method still accounts for a considerable proportion, indicating that it still has vitality. Hand-pasting method is characterized by wet resin molding, simple equipment, less expensive, and can paste more than 10m of the whole product at a time. The disadvantage is the low degree of mechanization, long production cycle, quality is not stable. In recent years, China has introduced from abroad extrusion, spraying, winding and other process equipment, with the development of the FRP industry, new process methods will continue to appear.
[edit]Usage
FRP is a composite material that has been developed rapidly in the past fifty years. Seventy percent of the production of glass fiber is used to make FRP. FRP is hard and much lighter than steel. Jet airplanes use it for fuel tanks and pipes, can reduce the weight of the aircraft. Astronauts on the moon, they are carrying a miniature oxygen tank, is also made of fiberglass. Fiberglass reinforced plastic is easy to process, not rust, not rotten, do not need paint. Our country has been widely used fiberglass fiber reinforced plastic manufacturing a variety of small motorboats, lifeboats, yachts, as well as automobile manufacturing, etc., saving a lot of steel. Can make fiberglass reinforced plastic tile, also known as transparent tile. Is and steel structure supporting the use of light materials, which is mainly composed of high-performance on the film, reinforced polyester and glass fiber, which on the film to play a very good anti-ultraviolet and anti-static role, anti-ultraviolet is to protect the polyester FRP light panels do not yellowing and aging, premature loss of light transmittance characteristics. Anti-static is to ensure that the surface of the dust is easily washed away by rain or blown away by the wind, to maintain a clean and beautiful surface. Because of its stable quality, durability, popular with customers, the product can be widely used in industrial/commercial/civil construction amount of roof and wall The film industry is used to make props, which is convenient, fast and cost-saving． It can imitate many kinds of material effects. It is welcomed by people. Chemical plants also use phenolic resin FRP instead of stainless steel to do a variety of corrosion-resistant equipment, greatly extending the life of the equipment. Fiberglass reinforced plastic is non-magnetic, does not block the passage of electromagnetic waves. Use it to do the missile radome, as if the missile put on a pair of protective glasses, not only does not block the radar "line of sight", but also play a protective role. Now, many missiles and ground radar station radomes are made of fiberglass. Into the 21st century, according to the good wave-transparent fiberglass, this aspect of the performance, with the widespread popularity of cell phone communications, fiberglass is widely used in the manufacture of 2G and 3G antenna cover, fiberglass with its good formability, the appearance of the beautification can be played a very good role in beautifying the community, the products in this regard are square column line cover, simulation of the stone, field application of the beautification of the tree and so on, fiberglass is also used to improve the water of the sports. The water of sports almost made a great contribution. Since the pole vault this sport, athletes use wooden pole to create the highest record is 3.05 meters. Later, bamboo poles were used. By 1942, the record was raised to 4.77 meters. The advantage of the bamboo pole is light and flexible, shortcomings is the lower end of the thick and thin upper end, and then to improve the record is very difficult, so people use aluminum alloy pole instead of bamboo pole, it is light and solid, but not flexible enough. In this way, from 1942 to 1957, fifteen years, the highest pole vault record only improved 1 cm. But since the emergence of the new fiberglass pole, because it is light and rich in elasticity, the record soared, today's pole vault record has exceeded the 6-meter mark. In today's world, fiberglass reinforced plastic is also used in a large number of people's lives, people affectionately called it "fiberglass", because of some of its special varieties can still retain many of the advantages of glass, such as transparency, so people use it as a window glass, not only to block the ultraviolet rays of the sun, but also to make the living room bright. People also use it to make a variety of durable daily necessities. Such as bath, kitchen utensils, washing utensils.
[Edit Paragraph]Market Application
FRP is a kind of composite material, FRP material because of its unique performance advantages, has been widely used in aerospace, railroad, decorative construction, home furniture, advertising display, handicrafts, building materials, sanitary ware, yacht berths, sports materials, sanitation projects and so on related to more than a dozen of industries, and well received by the praise, to become the material industry in the new era of business demand favorite. It has been widely used in more than ten industries, and has been highly praised, becoming the demanded favorite of the businessmen in the material industry in the new era. Fiberglass reinforced plastic (FRP) products are also different from the traditional material products, in terms of performance, use, life attributes are greatly superior to traditional products. Its easy to shape, can be customized, the characteristics of the color at will deployment, favored by merchants and sellers, occupies an increasingly large market score, a broad prospect! Specifically the following industries: ferrous metallurgy, non-ferrous metallurgy, electric power industry, coal industry, petrochemical industry, chemical industry, electromechanical industry, textile industry, automobile and motorcycle manufacturing, railroad industry, shipbuilding industry, construction industry, light industry, food industry, electronics industry, post and telecommunications, culture, sports and entertainment, agriculture, commerce, medicine and health care, as well as the military and civilian applications and other aspects of the Application fields. The main categories of FRP products involved in the application of these industrial sectors are: mine ventilation equipment, coking and related equipment, rare earth smelting and ferroalloy smelting related equipment, cold rolling and electroplating equipment, power transmission and transformation equipment, wind power generation equipment, thermal power generation with water pipes, cooling water equipment, power management and maintenance of appliances, coal mine phoenix tube, blasting water bags, explosion-proof devices, petroleum mining-related parts and equipment, petrochemical equipment, chemical equipment, chemical building with equipment, chemical equipment, chemical building materials, mine ventilation equipment, motor parts, spare parts, plating equipment, wind turbines and components, textile printing and dyeing equipment, facilities and components, automobile manufacturing materials and components, automotive maintenance materials, motorcycle manufacturing materials and components, railroad rolling stock materials and related facilities, railroad signaling system materials and related components, various types of rivers, lakes, and sea vessels, large steel Boat supporting parts and accessories, construction facilities and materials, bathrooms, kitchens, windows and doors, corrugated tiles, cooling towers, building ventilation and air-conditioning facilities, building templates, etc., light industry, daily-use chemical and paper industry-related facilities, household appliances, liquor, tanning, furniture materials, food storage tanks, electronic industrial equipment, consumer goods materials and electronic equipment accessories, postal and telecommunications equipment and facilities, sporting equipment, amusement equipment and related facilities, sports and recreational equipment, equipment and related facilities. equipment, amusement equipment and related facilities, agricultural sprinkler equipment, greenhouse, agricultural machinery accessories, cold storage, aquaculture, commercial counters, commercial packaging boxes, commercial cold storage, medical industry facilities and health care purposes and so on.