1. FRP definition
FRP is a kind of composite material, which is also called fiber reinforced polymer or fiber reinforced plastic. And FRP consists of the base material and reinforced material. In general, base materials are all kind of thermosetting resin. And the more common base materials are the epoxy resin and polyester resin. The reinforced material is often glass fiber, carbon fiber, or other fibers. According to using the different fiber for the reinforced material, we can divide FRP into glass fiber reinforced plastic, carbon fiber reinforced polymer, etc.
The diameter of the fiber is small, generally within 10 μm, and it is a fragile material. And it is easy to damage, fracture and corrosion. Compared with fibers, the polymer matrix has lower strength and modulus. But it can withstand the big strain and is a kind of tough material. Filling the fiber into the polymer matrix can effectively increase the strength and stiffness of the reinforced polymer.
2. FRP principle
Sometimes, one material can’t meet the needs of using, you need to combine two or more materials. They can form special materials which can satisfy you, and they are composite materials. For example, although the fiberglass material has good mechanical strength, the fibers are loose each other. It can only bear the tension, but unable to withstand bending, shear, and compressive stresses. Also, the glass fiber is hard to be made a fixed geometrical shape, it has a soft body. If you composite these glass fibers with polymer matrix together, you can make them into the final product with complex shapes and high stiffness. As a result, it can not only near the tension, but also bending shear, and compressive stress. This constitutes a fiberglass reinforced polymer matrix composite.
Furthermore, polymer matrix composites (PMCs) can be divided into reinforced plastic and advanced composites. For one thing, The reinforced plastic consists of the polyester resin and lower stiffness glass fibers. FRP manufacturers always use it in marine, automotive industry, pipe and tank, etc. For another, advanced polymer matrix composites consist of resins and fibers with high performance. They are mainly applicable in the aerospace industry. At the beginning of the composite materials development, people mainly use reinforcing glass fibers as the reinforced material. Now, they also adopt the carbon fiber, boron fiber, aramid fiber, alumina fiber, silicon carbide fiber, and so on. DOFRP is a leading FRP manufacturer of glass fibers and carbon fibers reinforced plastic products in China.
3. FRP properties
The reinforced plastic FRP has many advantages and disadvantages. For example, it has a lightweight, high tensile and yield strength, but also low elasticity modulus, poor long-term temperature resistance.
3.1 High strength
The relative density of the reinforced plastic is between 1.5 to 2.0, which is only to of the carbon steel. But it has high mechanical strength, such as the FRP tensile strength is close or even better than the carbon steel. The increase of the mechanical strength benefits from the join of glass fibers. And GFRP specific strength can be comparable to that of high-quality alloy steel. Therefore, FRP manufacturers mainly use it to produce the fiberglass product which needs to reduce its self-weight. For example, it has a pretty good effect on reducing the self-weight of aviation, rocket, spacecraft, heavy duty truck, and so on. If you adopt certain epoxy resin to produce GFRP, its tensile and yield strength can be up to over 400 MPa.
3.2 Corrosion resistance
Fiberglass reinforced plastic is a nice corrosion-resistant composite material. Because the thermosetting resin is involved in the production of FRP. In general, fiberglass products have 3 layers, the inner layer, the structural layer, and the external protection layer. To satisfy different working needs, you can adjust the resin content in fiberglass reinforced plastics. The more resins you use, the better anticorrosion performance FRP will have. What’s more, in order to use it in an acidic, alkaline, or neutral environment, you can choose different resin type.
3.3 Thermal insulation
The glass fiber reinforced plastic has a low thermal conductivity of 1.25-1.67 kJ/(m•h•K), which is only 1/100 to 1/1000 that of the metal. It is an excellent thermal insulated material. And DOFRP uses it to produce the FRP sandwich board of refrigerator van. When there is a super high temperature in an instant, the glass reinforced polymer is an ideal thermal insulated and ablation resistant material. It can protect the spacecraft from the erosion of the high-velocity air stream over 2000℃ high temperature.
3.4 Design flexibility
We can design complex shapes reinforced plastic products according to the customer’s different needs. Also, DOFRP can provide the final product with a full size, such as the auto body kit. What’s more, we can flexibly select the base material and reinforced material to satisfy the different mechanical properties. For example, the different polymer matrix is corrosion resistant to different using environment. And different fibers can provide different strength degree.
3.5 Diverse processes
There are many FRP manufacturing processes for customers to choose from. Firstly, the hand lay-up method is suitable for small-scale production. We can use it to supply large and complex shapes. Secondly, the resin transfer molding process is operated in a closed mold. The molding cycle is short, and the molded product has high precision. Thirdly, the filament winding process is an economic method. It uses the twistless roving and has a better cost effectiveness. Fourthly, the pultrusion process is greatly efficient, suitable for large-scale production and long dimension fiberglass products. Finally, the vacuum bagged method can be used for large dimension products, and they can be smooth for both sides.
3.6 Poor long-term temperature resistance
In general, you can’t use the fiberglass reinforced plastics under the pretty high temperature for a long time. The mechanical strength of GFRP with polyester resin will evidently decrease under the temperature over 50℃. And it is normally used below 100℃. Also, the strength of GFRP with epoxy resin will reduce over 60℃. But you can choose the high-temperature resistant resin, and it’s possible to make the long-term working temperature between 200℃ to 300℃.
3.7 Low shear strength
The shear strength of glass fiber reinforced plastic is realized with the help of resins. You can increase the strength by selecting the proper FRP process and surface treatment. The surface treatment is coating the surface conditioning agent in the fiberglass fabric surface. And the agent includes impregnating compound, a series of coupling agent and addition agent. Coupling agents can help to form a good bonding interface between fibre reinforced material and polymer matrixes. Therefore, it can increase the bonding strength and high performance of reinforced plastics, such as waterproof, wearproof and insulation.
4. FRP applications
The fiber reinforced polymer is a kind of composite material which develop rapidly in recent decades years. Around the world, the 70 percent of glass fibers yield is used to make FRP. The GFRP has a high stiffness but is much lighter than the steel. Some aircraft use it as the raw material of fuel tanks and pipes to reduce the plane weight. And astronauts landed on the moon, they carried miniature oxygen tanks which are also made of fiberglass. The GFRP is easy to process, rust and corrosion resistant. We have been using it to serve for aerospace, automotive, architecture, marine, transportation, etc.
In aerospace, FRP manufacturers provide radomes for aircraft. The rotating radome on aircraft is used for airborne early warning and control. And we install it on the top of the fuselage for 360-degree coverage. Fiberglass radomes can protect rotating antennas from the bird strike, ice, freezing rain, debris and rotational irregularities due to the wind. Therefore, they are good for increasing transmission efficiencies and reducing drag.
DOFRP has been supplying Hino with fiberglass truck bodies since 2006. We help them to reduce the body weight of heavy-duty trucks and increase their service life. Of course, we can also produce fiberglass hoods, fiberglass bumpers, fiberglass fairings, and other car body parts. As for the marine application, we provided marine radomes and military radomes. Many customers also find us to produce other fiberglass products, such as boat hull, for their ship, boat, and the yacht.
In the architecture and transportation industry, we not only manufacture fiberglass panels and pipes, but also parking barriers, highway guardrail, fiberglass signs, and so on. DOFRP also closely follow the step of the trend. With the advent of new energy vehicles, we have provided air conditioning cover and outer body shell for them.