Glass fiber reinforced plastic, glass fiber reinforced scientific name plastic, abroad, said: FRP --- Fiberglass-Reinforced Plastics glass fiber reinforced plastic, glass fiber reinforced plastic. FRP is abroad in the early 20th century developed a new type of composite materials, the development of fast, wide application, high-grade technology, has great vitality. In recent years, domestic glass steel, also have made great progress. The main characteristics of FRP are: lightweight, high strength, corrosion resistance, insulation, insulation, noise, long life and so on, its density is 1.5-2.0, 3-4 times lighter than steel, and high strength steel than 1.7 times, so mechanical properties and physical properties, and can replace steel, wood and cement, and some other materials. Glass fiber reinforced plastic products, is currently in the national defense, aviation, shipbuilding, automobiles, tourism, construction and civil and other fields, has been widely adopted, it will be high-quality brands of plastic composite material into the 21st century.
Glass fiber reinforced plastic (FRP) characteristics
(1) light-weight high-strength
Relative density between 1.5 ~ 2.0, only the steel of 1 / 4 to 1 / 5, but the tensile strength is close to, or even more than carbon steel, and the strength can be compared with the High-alloy steel. Therefore, in aviation, rocket, the universe, aircraft, high-pressure containers, as well as the need to reduce weight in other applications of the products are excellent results. Some epoxy FRP tensile, flexural and compressive strength can reach the more than 400Mpa. Part of the material density, intensity and strength shown in Table 1-1.
(2) good corrosion resistance
FRP is a good resistant materials, air, water and general concentration of acid, alkali, salt, and a variety of oils and solvents have better resistance to diseases. Has been applied to all aspects of chemical preservative, is replaced by carbon steel, stainless steel, wood and non-ferrous metals.
(3) good electrical properties
Is an excellent insulation material, used to make insulation. Still well under the protection of high-frequency dielectric properties. Microwave through the good, has been widely used in radar radome.
(4) good thermal performance
FRP low thermal conductivity at room temperature for 1.25 ~ 1.67kJ / (m h K), only metal 1 / 100 ~ 1 / 1000, is an excellent insulation material. Ultra-high temperature in the transient case, is the ideal ablation and thermal protection materials, to protect aircraft in the universe, more than 2000 ℃ washed under high-speed airflow.
(5) can be designed with good
① according to the needs of a variety of flexible design of the structure of products, to meet the application requirements, you can have a good product overall.
② can select materials to meet product performance, such as: can the design of the decay resistance of the instantaneous temperature, the product of a direction of a special high-strength, good dielectric properties, and so on.
(6) process of the fine
① products can be shape, technical requirements, uses and the flexibility to choose the number of molding process.
② process simple and can be a shape, highlight the economic effects, particularly in the shape of complex and difficult forming a small number of products, but also highlight the superiority of its technology.
Second, can not ask a FRP to meet all the requirements, FRP is not a panacea, FRP also has the following shortcomings.
(1) the low elastic modulus
FRP elastic modulus is two times bigger than the timber, but better than steel (E = 2.1 × 106) is 10 times, so often in the product mix is less than rigid, easy to deformation.
Shell structure can be made, mezzanine structures, can also be high modulus fibers to strengthen the tendons or so to make up for the form.
(2) poor long-term temperature
FRP can not generally long-term use under high temperature, general polyester FRP strength in more than 50 ℃ on the apparent decline in general only use the following at 100 ℃; general-purpose epoxy FRP in more than 60 ℃, the intensity has decreased significantly. However, the option of high temperature resistant resin, so that in the long-term operating temperature is 200 ~ 300 ℃ possible.
(3) aging
Aging is a common defect of plastic, FRP is no exception, in the UV, wind rain and snow yarn, chemical medium, under mechanical stress, such as easily lead to performance degradation.
(4) the low interlaminar shear strength
Interlaminar shear strength is borne by the resin, so very low. Through the choice of technology, such as the use of coupling agent to enhance the bond strength between layers, most notably in the product design as far as possible, to avoid inter-layer shear.