Advantages of FRP:
FRP is light and high strength; the relative density is between 1.5~2.0, only 1/4~1/5 of carbon steel, but the tensile strength is close to or even exceeds that of carbon steel, and the specific strength can be compared with high-grade alloy steel. Therefore, it has excellent results in aviation, rockets, spacecraft, high-pressure vessels and other applications that require weight reduction. The tensile, flexural and compressive strength of some epoxy FRP can reach more than 400Mpa.
Corrosion resistance; FRP is a good corrosion-resistant material, and has good resistance to the atmosphere, water and general concentrations of acids, alkalis, salts, and various 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, etc.
Good electrical properties are excellent insulating materials used to make insulators. It still protects good dielectric properties at high frequencies. It has good microwave permeability and has been widely used in radomes.
Good thermal performance; FRP has low thermal conductivity, 1.25~1.67kJ/(m·h·K) at room temperature, which is only 1/100~1/1000 of metal. It is an excellent thermal insulation material. In the case of instantaneous ultra-high temperature, it is an ideal thermal protection and ablation resistant material, which can protect the spacecraft from the erosion of high-speed airflow above 2000 °C.
Good designability;
(1) Various structural products can be flexibly designed according to needs to meet the requirements of use, which can make the product have a good integrity.
(2) The material can be fully selected to meet the performance of the product, such as: corrosion resistance, instantaneous high temperature resistance, special high strength in a certain direction of the product, good dielectric properties, etc. can be designed.
Excellent workmanship;
(1) The molding process can be flexibly selected according to the shape, technical requirements, use and quantity of the product.
(2) The process is simple, it can be formed at one time, and the economic effect is outstanding, especially for products with complex shapes and a small number of products that are not easy to form, its technological superiority is more prominent.
Disadvantages of FRP:
The elastic modulus of FRP is low; the elastic modulus of FRP is twice larger than that of wood, but 10 times smaller than that of steel (E=2.1×105), so it often feels insufficient rigidity in the product structure and is easy to deform.
It can be made into a thin shell structure, a sandwich structure, and can also be compensated by high-modulus fibers or reinforcing ribs.
Poor long-term temperature resistance; general FRP cannot be used for a long time at high temperature, and the strength of general-purpose polyester FRP decreases significantly when it is above 50 °C, and is generally only used below 100 °C; general-purpose epoxy FRP is above 60 °C, the strength is significantly reduced. However, high temperature resistant resin can be selected, so that the long-term working temperature is possible at 200~300℃.
Aging phenomenon: Aging phenomenon is a common defect of plastics, and FRP is no exception. It is easy to cause performance degradation under the action of ultraviolet rays, wind, sand, rain and snow, chemical media, and mechanical stress.
The shear strength is low; the interlaminar shear strength is borne by the resin, so it is very low. The interlayer adhesion can be improved by selecting a process and using a coupling agent. The most important thing is to avoid shearing between the layers as much as possible during product design.