Physical and Chemical Properties of Polyimide Composites

Since the 1960s, high-performance polymers have been widely used in aerospace, defense, military, electronics, and nuclear industries as heat-resistant, high-strength, high-modulus structural materials and high-temperature electrical insulating materials. Small, it occupies a very important position.

Polyimide has excellent electrical and mechanical properties, high thermal stability, thermal oxidative and chemical stability, small thermal expansion coefficient, good solvent resistance, dimensional stability and good processing flow. , Easy-to-mold and high-precision parts with complex shapes and many other excellent properties, its series of products can be used to prepare high-performance plastic products, and has become a promising development in the aerospace, electronics, nuclear power, communications and automotive and other cutting-edge technology areas. The main material.

Thermosetting polyimide resin is an opaque solid, an insoluble, infusible high molecular polymer with a relative density of 1.5. It has no melting point and glass transition point below 500°C. It is stable below 420°C and is insoluble in most organics. Solvents, with outstanding high temperature resistance, can be used continuously at higher temperatures of 260°C, and can maintain good mechanical and electrical properties. Its own good impact resistance, fatigue stability and dimensional stability, no cracking, no cold flow, with excellent resistance to heat radiation and good chemical resistance and abrasion resistance and self-lubrication, its own Good flame retardancy, only scorch and decompose at high temperatures, no ignition.

Thermoplastic polyimide resins have comprehensive physical and mechanical properties and a relative density of 1.38. The glass transition temperature is 275°C. Has good wear resistance, radiation resistance and electrical insulation, but the heat resistance is not as good as thermoset polyimide.

Polyamide imide is one of the modified products of polyimide. Its advantage is that the heat distortion temperature is as high as 276°C, and its new applications are being exploited in terms of processability and the like.

The new insoluble, infusible polyamideimide resin is resistant to high temperatures and radiation and has good electrical insulation. It can be decomposed at 450°C for a long period of time under C. It can be modified by cross-linking with an epoxy resin. It is resistant to ablation and has good electromagnetic properties at high temperatures and high frequencies.

The soluble polyimide resin can be 100% solidified in the solvent to be in a dissolved state. The curing temperature is the boiling point of the solvent or the temperature at which the solvent can fully volatilize. The curing temperature is 150-200° C., and the soluble resin is in the production process. The aromatic resin, such as alkyl, amino or cyclopentane, is introduced into a soluble resin.

The curing temperature of the low-temperature-curing polyimide resin is lower than 200° C., and it has good heat resistance, good electrical insulation, good adhesiveness with the inorganic film, low elasticity, and good encapsulation.

The nano-polyimide composite material refers to a composite material in which the size of the dispersed phase is at least one dimension less than 100 nm. Due to the nano-scale effect, the large specific surface area of ​​the dispersed phase and the stronger interfacial bonding with the matrix, the nano-composite material generally exhibits more excellent physical and chemical properties than the composite material of the same composition.

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