| Use | Applications Polyimides have been used for a long time in the microelectronics industry, mainly as insulating layers and packaging materials, especially in the multi-layer interconnection to form planar layers and multi-module space Isolation. In 1908, the first aromatic form of polyimide was successfully synthesized, and then the bulk material and the spin-coated form of the material were used in a series of applications. Products of the HD MicroSystems(Parlin,NJ) and DuPont(Wilmington,DE) brands can then be purchased and first introduced into MEMS as flexible substrates. Fabrication of sensors and multi-electrode arrays. Applied in the biomedical field. |
Polyimide is a polymer material with high heat resistance and electrical insulation properties, commonly used in the manufacturing of insulation components in electrical and electronic equipment. It has excellent electrical performance, heat resistance, and chemical resistance, and is commonly used in electrical insulation materials, cable insulation sleeves, and other fields in high-temperature environments.
Nature:
1. Polyimide has high heat resistance and can withstand high temperatures up to 250 ° C or above.
2. It has excellent electrical insulation performance and can maintain good insulation performance under high voltage.
3. Strong chemical resistance and good corrosion resistance.
4. Has good mechanical strength and stability.
Usage:
1. Electrical insulation materials: used to manufacture insulation components in electrical and electronic equipment, such as cable insulation sleeves, insulation gaskets, etc.
2. Automotive components: Used to manufacture components inside the engine compartment of a car, such as cooling fan blades.
3. Chemical pipelines: can be used to manufacture chemical pipelines and containers with high corrosion resistance requirements.
Method:
The preparation method of polyimide mainly includes the synthesis of polyimide resin, resin processing into products, and other steps. The preparation process requires certain process conditions and operating techniques, usually produced by professional manufacturers.
Security information:
1. During the processing, attention should be paid to good ventilation to avoid inhaling its volatile components and causing poisoning.
2. Avoid contact with skin and eyes. If touched, rinse immediately with plenty of water and seek medical help.
3. Store away from open flames and heat sources, avoiding high temperatures and direct sunlight.
4. Avoid contact with strong oxidants, strong acids and bases, and other chemical substances to avoid chemical reactions.
overview
polyimide is an aromatic heterocyclic polymer compound with imide-based chain links in its molecular structure. its English name is Polyimide (PI for short). it is one of the most heat-resistant varieties in engineering plastics at present. As a special engineering material, PI has been widely used in aviation, aerospace, microelectronics, nano, liquid crystal, separation membrane, laser and other fields.
Properties of polyimide
1. according to thermogravimetric analysis, the initial decomposition temperature of all aromatic polyimide is generally about 500 ℃. Polyimide synthesized from biphenyldianhydride and p-phenylenediamine has a thermal decomposition temperature of 600 ℃, which is one of the varieties with the highest thermal stability in polymers so far.
2. Polyimide can withstand extremely low temperatures, such as it will not brittle in liquid helium at -269°C.
3. polyimide has excellent mechanical properties. the tensile strength of unfilled plastics is above 100Mpa, the film (Kapton) of phenylene polyimide is above 170Mpa, and the biphenyl polyimide (UpilexS) reaches 400Mpa. As an engineering plastic, the amount of elastic membrane is usually 3-4Gpa, and the fiber can reach 200Gpa. According to theoretical calculations, the fiber synthesized by terephthalic anhydride and p-phenylenediamine can reach 500Gpa, second only to carbon fiber.
4. Some polyimide varieties are insoluble in organic solvents and are stable to dilute acids. General varieties are not very resistant to hydrolysis. This seemingly defective performance makes polyimide different from other high-performance polymers. A big feature is that alkaline hydrolysis can be used to recover raw dianhydride and diamine. For example, for Kapton film, the recovery rate can reach 80%-90%. Changing the structure can also obtain varieties that are quite resistant to hydrolysis, such as withstanding 120 ℃ and boiling for 500 hours.
5. The thermal expansion coefficient of polyimide is 2 × 10-5-3 × 10-5 ℃, Guangcheng thermoplastic polyimide is 3 × 10-5 ℃, biphenyl type can reach 10-6 ℃, and individual varieties can reach 10-7 ℃.
6. Polyimide has high radiation resistance, and its film has a strength retention rate of 90% after 5 × 109rad fast electron irradiation.
7. polyimide has good dielectric properties. the dielectric constant is about 3.4. if fluorine is introduced or air nanometer size is dispersed in polyimide, the dielectric constant can be reduced to about 2.5. Dielectric loss is 10-3, dielectric strength is 100-300KV/mm, Guangcheng thermoplastic polyimide is 300KV/mm, volume resistance is 1017 Ω/cm. These properties can still be maintained at a high level over a wide temperature range and frequency range.
8. polyimide is a self-extinguishing polymer with low smoking rate.
9. polyimide has very little gas under extremely high vacuum.
10. Polyimide is non-toxic and can be used to make tableware and medical utensils, and can withstand thousands of disinfections. Some polyimides also have good biocompatibility. For example, they are non-hemolytic in blood compatibility experiments and non-toxic in vitro cytotoxicity experiments.
material properties
Early polyimide relied on its low Young's modulus and ability as a flexible substrate as a MEMS material application. This substrate has the potential for biocompatibility and biostability in biomedical applications. Preliminary studies have demonstrated its inertness and low cytotoxicity. The biocompatibility of polyimide supports implantation of microelectrodes has been verified. However, some manufacturers have made it clear that their polyimide is prohibited from being used on implantable devices. In addition, compared with other film polymers (such as parylene and PDMS), polyimide is harder and can cause minor nerve tissue damage. Other notable features of polyimides include high glass transition temperature, high thermal and chemical stability, low dielectric constant, high mechanical strength, low water absorption and high solvent resistance. These functional combinations enable polyimide to be used as a substitute for ceramics, a chemical-resistant electroplating film, and a sacrificial layer.