FRP is a kind of composite material with rapid development in recent 50 years. 70% of the output of glass fiber is used to make FRP. FRP has high hardness and is much lighter than steel. Glass fiber reinforced plastic (FRP), also known as GFRP, is a fiber reinforced plastic. It generally refers to the matrix of unsaturated polyester, epoxy resin and phenolic resin reinforced with glass fiber. Reinforced plastics with glass fiber or its products as reinforcing materials are called glass fiber reinforced plastics, or FRP, which is different from tempered glass.
Fiber reinforced composites are composed of reinforcing fibers and matrix. The diameter of fiber (or whisker) is very small, usually 10 μ Below m, there are few and small defects, and the fracture strain is less than 30 thousandths. It is a brittle material, which is easy to damage, fracture and corrosion. Compared with the matrix, the elastic modulus of the fiber is low, but it can withstand a lot of viscoelastic and elastic strength.
Glass has high hardness but fragile, good transparency, high temperature resistance, corrosion resistance of FRP cooling tower, etc; At the same time, steel is hard and not fragile, but also has the characteristics of high temperature resistance. So people began to think that if we can make a material that not only has the hardness, high temperature resistance and corrosion resistance of glass, but also has the characteristics of hard and unbreakable like steel, this material will be of great use.
According to statistics, the characteristics of FRP mainly include the following aspects:
Light weight and high strength
The relative density is between 1.5 ~ 2.0, which is only 1 / 4 ~ 1 / 5 of that of carbon steel, but the tensile strength is close to or even higher than that of 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 vessels and other products that need to reduce self weight. The tensile, bending and compressive strength of some epoxy FRP can reach more than 400MPa.
Corrosion resistance
FRP is a good corrosion-resistant material, which has good resistance to atmosphere, water, general concentration of acid, alkali, salt, as well as 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 performance
It is an excellent insulating material used to make insulators. It can still protect good dielectric at high frequency. With good microwave transmission, it has been widely used in radar radon.
Good thermal performance
FRP has low thermal conductivity, which is 1.25 ~ 1.67kj / (m · h · K) at room temperature, only 1 / 100 ~ 1 / 1000 of metal. It is an excellent thermal insulation material. Under the condition of instantaneous ultra-high temperature, it is an ideal thermal protection and ablation resistant material, which can protect the spacecraft from the scouring of high-speed airflow above 2000 ℃.
Good design-ability
(1) Various structural products can be flexibly designed according to the needs to meet the use requirements, which can make the products have good integrity.
(2) Materials can be fully selected to meet the performance of products, such as corrosion-resistant, instantaneous high temperature resistant, products with special high strength in a certain direction, good dielectric, etc.
shortcoming
Low elastic modulus
The elastic modulus of FRP is twice that of wood, but higher than that of steel (E = 2.1 × 10) It is 10 times smaller, so it often feels insufficient rigidity and easy to deform in the product structure.
It can be made into thin shell structure, sandwich structure, high modulus fiber or stiffener.
Poor long-term temperature resistance
General FRP cannot be used for a long time at high temperature. The strength of general polyester FRP decreases significantly above 50 ℃, and it is generally only used below 100 ℃; The strength of general-purpose epoxy FRP decreased significantly when the temperature was above 60 ℃. However, high temperature resistant resin can be selected, so that it is possible to keep the long-term working temperature at 200 ~ 300 ℃.
Aging phenomenon
Aging is a common defect of plastics, and FRP is no exception. Under the action of ultraviolet light, wind, sand, rain and snow, chemical medium, mechanical stress and so on, it is easy to cause performance degradation.
FRP is a kind of composite material. Because of its unique performance advantages, FRP has been widely used in more than ten related industries, such as aerospace, railway, decorative architecture, home furniture, advertising display, craft gifts, building materials and sanitary ware, yacht berthing, sports materials, environmental sanitation engineering and so on. It has been highly praised and has become the demand pet of merchants in the material industry in the new era. FRP products are also different from traditional material products, which are much better than traditional products in performance, use and service life. With the characteristics of easy modeling, customize and random color allocation, it is deeply favored by merchants and sellers, occupies an increasing market score and has broad prospects!