High-performance engineering plastic polyimide, is widely used in various fields due to its excellent thermal stability, mechanical strength, and electrical properties. With the advancement of technology, the application prospects of polyimide are becoming even broader, particularly in aerospace, electronics, and chemical industries, where it demonstrates unique advantages.
1、Thermal Stability
Polyimide (PI) exhibits exceptional thermal stability, with decomposition temperatures typically ranging from 500°C to 600°C. Compared to many other polymer materials, polyimide maintains excellent structural stability at high temperatures, without melting or decomposing. This makes it ideal for high-temperature applications in aerospace and automotive industries, where it provides long-term thermal protection, preventing performance degradation under extreme temperatures. Additionally, polyimide has good thermal cycling stability, maintaining its physical and mechanical properties even during repeated heating and cooling cycles.
2、Mechanical Properties
Polyimide has outstanding mechanical properties, with a tensile strength typically exceeding 100 MPa, giving it high tensile strength and toughness. In applications requiring high mechanical strength and wear resistance, polyimide can effectively withstand external pressure and stretching forces. It also has excellent impact resistance and fatigue strength, maintaining high strength over long-term use. This makes it particularly suitable for high-speed rotating mechanical components, aerospace parts, and critical automotive engine components.
3、Dielectric Properties
Polyimide also has exceptional electrical properties, particularly its dielectric constant, which is typically around 3.4, much lower than traditional plastic materials. This helps reduce electromagnetic interference. Its dielectric strength ranges from 150 to 300 kV/mm, which means PI polyimide plastic can operate stably under high voltage conditions without electrical breakdown. Due to these excellent electrical properties, polyimide is widely used in the electronics industry for flexible circuit boards, electronic packaging materials, and motor insulation materials, ensuring the long-term stability and safety of these high-precision devices.
4、Cold Resistance
Polyimide is not only stable in high-temperature environments but also exhibits excellent cold resistance. Certain specially designed polyimide materials maintain good toughness and structural integrity in liquid nitrogen environments at -269°C, without becoming brittle. This makes polyimide widely used in deep space exploration, polar research, and low-temperature refrigeration equipment. Polyimide provides excellent performance support in spacecraft external protective materials, space exploration devices, and low-temperature sensors.
5、Chemical Stability
The chemical stability of polyimide is another significant advantage. It has excellent resistance to acids, bases, solvents, and other chemicals, maintaining its structure even in extreme chemical environments. Some polyimides are almost insoluble in any organic solvents and exhibit outstanding hydrolysis resistance. Due to its excellent corrosion resistance, polyimide is widely used in the chemical industry and electronic equipment, especially in applications such as chemical reactor linings, corrosion-resistant pipes, membranes, and packaging materials.
6、Low Coefficient of Thermal Expansion
The coefficient of thermal expansion of standard polyimide is between 40-50 ppm/°C, while biphenyl-based polyimide has an even lower coefficient. This means polyimide undergoes relatively small dimensional changes when subjected to temperature variations, offering excellent dimensional stability. This property makes polyimide widely used in high-precision electronic devices and optical components. For example, polyimide can effectively prevent performance loss due to thermal expansion in the production of precision sensors, lasers, optical communication devices, and electronic components, ensuring long-term stable operation of these devices.
7、Radiation Resistance
Polyimide materials have excellent radiation resistance. Even when exposed to high levels of radiation, its physical properties and strength remain more than 90% intact. This makes polyimide widely used in nuclear energy, aerospace, and high-energy physics research. For example, spacecraft are exposed to cosmic radiation for extended periods, and polyimide ensures that the spacecraft can maintain structural integrity and the long-term stability of equipment in such harsh radiation environments.
8、Self-extinguishing Property
Polyimide, as a self-extinguishing polymer material, can automatically extinguish when exposed to open flames and has a low smoke emission rate. This feature makes polyimide extremely safe in high-risk fire environments, widely used in electrical equipment, building materials, and aerospace applications. For example, polyimide is often used for cables and electronic devices in airplane cabins, as it not only effectively prevents fire spread but also reduces harmful smoke produced during fires, ensuring the safety of personnel.
9、Non-toxicity
Polyimide is a non-toxic material that does not release harmful substances during use. It has been certified for use in food contact materials and is used for plastic tableware, trays, and medical devices. Polyimide’s application in the medical field is also expanding, particularly in biomedical devices such as artificial organs and drug delivery systems, where its non-toxicity makes it an ideal material. Additionally, polyimide is used in high-performance protective equipment and materials in contact with the human body, ensuring safety during use.
The exceptional properties of polyimide make it an ideal choice for many advanced technological applications. With the continuous progress of future technologies, polyimide will continue to provide stable and efficient solutions across industries, driving technological innovation and development.