What is glass reinforced plastic?
Glass fiber reinforced plastics, is a variety of different performance, a wide range of USES of composite materials.
It is a new functional material made of synthetic resin and glass fiber by composite process.
Characteristics of glass fiber reinforced plastics:
(1) good corrosion resistance: FRP is a good corrosion resistant material for the atmosphere;
Water and generally concentrated acids and bases;
Salt and a variety of oils and solvents have good resistance, has been widely used in various aspects of chemical anti-corrosion.
Replacing carbon steel;
Nonferrous metals and other materials.
(2) light and high strength: the relative density of FRP is between 1.5~2.0, only 1/4~1/5 of carbon steel, but the tensile strength is close to or even more than carbon steel, and the strength can be compared with high-grade alloy steel, is widely used in aerospace;
High pressure vessels and other products that need to reduce self weight.
(3) good electrical performance: FRP is an excellent insulating material, which is used in the manufacture of insulators and can be kept in good condition at high frequency.
(4) good thermal performance: FRP conductivity is low, at room temperature 1.25~1.67KJ, only 1/100~1/1000 of metal is a good insulation material.
It is an ideal material for thermal protection and ablative resistance under transient ultra-high heat.
(5) excellent process performance: the molding process can be selected according to the shape of the product and the process is simple and can be formed at one time.
(6) good designability: materials can be fully selected to meet the requirements of product performance and structure.
(7) low modulus of elasticity: the modulus of elasticity of FRP is 2 times larger than that of wood but 10 times smaller than that of steel. Therefore, it is often found that rigidity is insufficient and deformation is easy in the product structure.
The solution can be made into a thin shell structure;
Sandwich structures can also be made up in the form of high-modulus fibers or stiffeners.
(8) poor long-term temperature resistance: general FRP cannot be used for a long time under high temperature. The strength of universal polyester resin FRP will decrease obviously when it is over 50 ° c.
(9) aging phenomenon: in the ultraviolet;
Wind, rain and snow;
Mechanical stress is easy to lead to performance degradation.
(10) low interlaminar shear strength: interlaminar shear strength is assumed by resin, so it is relatively low.
The interlayer adhesion can be improved by selecting process and using coupling agent, and the interlayer shear can be avoided as far as possible in product design.
Advantages of glass fiber reinforced plastics:
Glass fiber reinforced plastics, especially nylon plastics, can withstand much higher temperatures than glass fiber
Glass fiber reinforced plastics have low shrinkage and high rigidity.
Glass fiber reinforced plastics will not stress crack, at the same time, glass fiber reinforced plastics impact resistance is much improved
Glass fiber reinforced plastics have high strength, such as tensile strength, compression strength, bending strength.
Because of the addition of other auxiliaries, the combustion performance of glass fiber reinforced plastics decreases a lot.
Disadvantages of glass fiber reinforced plastics:
The addition of glass fiber reinforced plastics makes the plastic opaque, as it was before the glass fiber was added.
Plastic-glass fiber reinforced plastics have lower toughness and higher brittleness than glass fiber reinforced plastics.
Plastic glass fiber reinforced plastics due to the addition of glass fiber, the melt viscosity of all materials increased, liquidity became poor, injection pressure than no glass fiber to increase a lot, in order to normal injection, the injection temperature of all reinforced plastics than no glass fiber before increased 10℃-30℃.
Because of the join of glass fiber and auxiliary agent, the hygroscopic property of glass fiber reinforced plastic is strengthened greatly, what original pure plastic does not absorb water also can become bibulous, accordingly, should enter when injection molding dry.
During injection molding, glass fiber reinforced plastics can enter the surface of plastic products, making the surface become very rough and dotted.
In order to obtain a higher surface quality, it is best to use the mold heating machine when injection molding, so that the plastic polymer into the surface of the product, but can not achieve the appearance of pure plastic quality.
After the enhancement of glass fiber, glass fiber is a material with high hardness, and the high temperature volatilization of auxiliary agent is a corrosive gas, which has a great wear and corrosion on the screw and injection mold of the injection molding machine. Therefore, when producing the mold and injection molding machine with this kind of material, it is necessary to pay attention to the anti-corrosion treatment and surface hardness treatment of the equipment