Plastic
Application Of Plastic Injection Molding in Aerospace Field
On April 29, the Long March 5B Yao-2 carrier rocket carried the "Tianhe Core Module" of the space station and launched at the Wenchang Space Launch Site in Hainan. At present, the "Tianhe Core Module" of the Chinese space station has been launched into orbit. The Tianhe core module is an integral part of the Chinese space station "Tiangong".
As we all know, in the aerospace field, the requirements for materials and technical levels are relatively strict. The plastics used in the "Tianhe Core Cabin" are also high-strength and high-temperature resistant materials. Which plastics will be used in cutting-edge technology?
1. Polycarbonate (PC)
Polycarbonate PC is an advanced aerospace composite resin, and it is also the most advanced plastic on the market, commonly known as bulletproof glue. It has excellent comprehensive properties: high mechanical strength, good toughness, extremely high impact strength, good heat and weather resistance, good transparency, high dimensional accuracy and stability, easy coloring, low water absorption, and can be used for a long time at 120 ~ 130 ℃ Use at working temperature.
Flame Retardant PC Plastic Granules
Different from other plastic materials, PC resin is non-toxic and tasteless, and does not release any harmful substances. Its unique structural characteristics such as flame retardant, wear resistance, and oxidation resistance make it widely used in medical, military, aerospace, protection, etc. and other special fields.
The application of PC in the field of aviation and aerospace technology is also increasing day by day. PC laminates are widely used in aircraft canopies, lighting equipment, industrial safety baffles and bulletproof glass. According to statistics, there are 2,500 polycarbonate parts used in a Boeing aircraft alone, and a single aircraft consumes about 2 tons of PC, while hundreds of PC parts with different configurations and reinforced by glass fiber are used in the spacecraft. and protective equipment for astronauts.
2. Polyamide (PA)
Modified nylon new material is an important material basis for the development of aerospace technology. The birth of a new generation of aerospace products is often based on the successful development of a large number of advanced new materials, and can also drive the rapid start and application of many new material projects.
Modified nylon material is an important supporting material for my country's aerospace industry, mainly including rubber, engineering plastics, adhesives and sealants.
Description of nylon products: outstanding wear resistance, its friction coefficient is usually 0.1-0.3 as phenolic plastic cloth 1/4, 1/3 of Baalloy is an excellent self-lubricating material with good mechanical properties. Nylon products have high hardness, high tensile strength, bending resistance and impact strength and high elongation. Its compressive strength is comparable to that of metals, and its fatigue strength is on the same level as cast iron and aluminum alloys. Stable chemical stability, it is not affected by chemicals whether it is weak bases, alcohols, hydrocarbons, and oils. It has the characteristics of light specific gravity, good toughness, strong wear resistance, oil resistance and shock resistance. Such as turbines, gears, bearings, impellers, blades, screw rods, high pressure washers, sealing rings, nuts, screws, shuttles, sleeves, bushing connectors, etc.
The world's major aerospace companies and aircraft manufacturers are looking for composite materials that are reliable, adaptable, easy to process, and highly resistant to damaging accidents. As the earliest thermoplastic material applied in the aerospace field, modified nylon has now become an indispensable part of aerospace materials.
Modified nylon has strong radiation resistance and can be used as a coating material for special envoy materials such as aircraft and satellites; its excellent mechanical properties can be made into various heat-resistant connectors for aircraft, and weather-resistant and creep-resistant radomes; Carbon fiber and glass fiber reinforced composite materials based on PEKK can be used in aircraft and spacecraft cabins, door handles, joysticks, and helicopter tails. Its excellent flame retardant properties, low smoke generation and toxic gas release during combustion, are often used to manufacture internal parts of aircraft; it can also be used to manufacture rocket battery slots, bolts, nuts and internal parts of rocket engines.
3. Polyetheretherketone (PEEK)
Polyetheretherketone resin was first used in the aerospace field. Used to replace aluminum, titanium and other metal materials to manufacture aircraft interior and exterior parts.
PEEK belongs to low density, good processing performance, and can be directly processed into precision parts. PEEK's good hydrolysis resistance and corrosion resistance are used to make aircraft exterior parts. PEEK itself has excellent flame retardancy and is often used for internal parts of aircraft.
Specific application components of PEEK in aircraft:
(1) Engine
The primary properties of PEEK in most engine applications are high temperature resistance and frictional interaction when in contact with lubricating materials. The PEEK material can be used for a long time at a temperature of 260 degrees and can withstand the local overheating of the engine.
(2) Aircraft exterior parts
The wear resistance of jet aircraft exterior parts depends on the impact of raindrops or microscopic substances on the surface of the material. The test surface PEEK has good rain erosion resistance.
(3) Aircraft interior parts
PEEK's outstanding flame retardant properties, mechanical properties, creep resistance and fatigue resistance are fully demonstrated by the requirements of air transportation applications, two weights and easier processing than ordinary structural materials, suitable for manufacturing: transformer housings, battery racks, and fuel pipe brackets, etc.
(4) Engine fairing
Finishing covers on the wings to streamline airflow around the interwing strut assemblies of the painted engines. Such large parts are usually made of low-density metal, which has been replaced by PEEK. The current Boeing 757-200 family of aircraft uses PEEK fairings with an exemplary service record, suggesting that it may be used on other similar high-performance components.
4. Polyaryletherketone (PEAK)
Polyaryletherketone is a kind of polymer in which phenylene rings are connected by ether bonds and carbonyl groups. Many different polymers can be formed according to the connection order and ratio of ether bonds, ketone groups and benzene rings in the molecular chain.
Due to the rigid benzene ring in the molecular structure, PEAK has good high temperature resistance, excellent chemical corrosion resistance and radiation resistance. The ether bond in the molecular structure makes it flexible, so it can be processed by the processing method of thermoplastic engineering plastics.
As an important special engineering plastic, PEAK is expensive and is mostly used in the aerospace field related to high technology, or some structural components in the automotive industry, electrical and electronic industry and machinery industry with relatively high technical requirements.
5. Liquid Crystal Polymer (LCP)
LCP refers to a polymer material that can form a liquid crystal state under certain conditions, and is one of the fastest-growing new materials in recent years.
The characteristics of LCP are high strength, wear resistance, high temperature resistance, flame retardant, low smoke output, good chemical stability and excellent electrical insulation. In aerospace, aviation, military industry and other fields, it has a wide range of application prospects and can be used for various parts inside the aircraft.
6. Polyimide (PI)
PI is the earliest special engineering plastic with high temperature resistance and high strength, and occupies an extremely important position in heat-resistant engineering plastics. PI has excellent radiation resistance and corona resistance is better than other engineering plastics. At the same time, PI is resistant to high temperature and low temperature, high tensile strength, and wear resistance.
PI can be used in the aerospace field, such as aircraft engine parts, aircraft internal structural parts, etc.
7. ABS plastic
ABS is a terpolymer formed by graft copolymerization of acrylonitrile, butadiene and styrene monomers. It has the common properties of three components, tough, hard and rigid, and belongs to thermoplastics.
The most prominent feature of ABS is its excellent impact resistance, high strength, good wear resistance and chemical corrosion resistance. Due to technological progress, production cost reduction, and wide application, ABS has now been changed from the original engineering plastic to a general-purpose plastic, becoming one of the five general-purpose plastics.
In the aviation industry, the application of ABS plastics on aircraft is gradually increasing, such as for instrument panels, hoods, etc.
8. Polyimide (PI)
Polyimide (PI) is an organic polymer material with obvious comprehensive properties, known as "one of the most promising engineering plastics in the 21st century", and is the most high-temperature resistant polymer material that can be practically applied so far. Polyimide can be subdivided into PI foam, PI film, PI fiber, PI matrix composite material, PSPI and other products, with high insulation strength, solvent resistance, radiation resistance, thermal insulation, non-toxic, sound absorption and noise reduction, Easy to install and maintain.
As an advanced composite material and one of the most high-temperature-resistant structural materials, polyimide has a wide range of application temperatures. It can work in the environment of -200 to 300 °C for a long time, and can withstand high temperatures above 400 °C for a short time. To cope with the temperature difference of up to 356°C between day and night on the lunar surface, it can resist radiation and improve the thermal environment of spacecraft. It is widely used in aerospace, aircraft, rocket parts and astronauts' protective equipment.
9. SiC fiber
Carbon fiber can strengthen the plastic fuselage panel and provide stronger rigidity for the body of the spacecraft; and silicon carbide fiber (SiC fiber) is another new type of high-performance fiber developed after carbon fiber, which is a national strategic emerging material. At present, the application value of ceramic matrix composites made of silicon carbide fibers in the field of aero-engines is very significant. Western developed countries have successfully applied such products to improve many parts of aero-engines and improve the efficiency of aero-engines.
One of the main uses of SiC fibers is to make SiC composite ceramic matrix materials (CMC materials). In the field of aero-engines, the application of CMC materials can further increase the temperature of the turbine intake air, thereby improving engine efficiency. At the same time, the CMC material reduces the structural density, achieves light weight, and improves the thrust-to-weight ratio of the aircraft. Therefore, SiC composite ceramic-based materials are considered to be ideal materials for thermal structural components of near-space vehicles and reusable spacecraft, and their research and development and applications have been highly valued by mainstream institutions and aero-engine manufacturers. At present, manufacturers in western developed countries have applied CMC materials to many hot-end components of aero-engines, mainly including engine tail nozzles, turbine stator blades, nozzle adjustment pieces, combustion chamber flame tubes and other parts.
With the further improvement of the performance of silicon carbide fiber and the gradual optimization of the production process, the material is expected to be applied to more aero-engine components in the future, and is expected to be expanded to other high-value civil fields, with a broad potential market space.
10. Other plastic materials
In addition, there are many plastic materials used in the aerospace field. Polycarbonate (PC) is an advanced aerospace composite resin, widely used in aircraft canopies, lighting equipment, astronauts' protective equipment, etc. Modified nylon has strong radiation resistance and can be used as aircraft, satellites, etc. The coating material of the special envoy material; polyether ether ketone resin (PEEK) is used in the aerospace field to replace aluminum, titanium and other metal materials to manufacture spacecraft engines, internal and external parts; polyaryl ether ketone (PEAK) has good high temperature resistance. ABS type, chemical corrosion resistance and radiation resistance are also very good; ABS has excellent impact resistance, high strength, good wear resistance, chemical corrosion resistance, and its application in the aviation industry is gradually increasing, such as instrument panels, hoods, etc. , can reduce flight weight. As a comprehensive service platform for the plasticization industry chain, Jinsubao covers nearly 180,000 kinds of raw materials and products in the plasticization field such as PVC, PP, PC, PA66, PE, PEEK, etc. Through the Jinsubao platform, you can purchase these products online with one click. plastic raw materials.
Can reduce aircraft weight.
Today, with the rapid development of science and technology, there may be more engineering plastics and modified plastics on the application stage, and we will continue to pay attention.