Polyphenylene

1. Introduction to polyphenylester
Polyphenyl ester is also known as polyparaben or aromatic polyester, abbreviated as AP in English.
The performance of polyphenyl ester is closest to that of metal, it can be used for a long time at 315 °C, and the short-term use temperature can be as high as 370~425 °C, and the thermal conductivity is the highest among thermoplastics. Among the known plastics, they have the best heat resistance, self-lubrication, hardness, electrical insulation and wear resistance.
2. Structural performance
(1) General performance The water absorption rate is low, only 1/4 of polyimide (PI), almost the same as F4.
(2) Mechanical properties It has high rigidity in a wide range of temperatures, the flexural modulus is twice that of PI, and the strength and modulus decrease with the increase of temperature, and the strength decreases rapidly. Good creep resistance, excellent self-lubricability, friction coefficient with steel is 0.3, good wear resistance, large limit PV value, after adding 20% F4 to AP, the PV value can reach 2.5MPa.m/s, which is larger than the PV value of porous bronze bearing with lubricating oil.
(3) Thermal performance AP does not melt when heated to 538 °C, and only occurs a viscous flow similar to metal at 427 °C, and there is no obvious decomposition phenomenon below 325 °C, and the decomposition is aggravated above 425 °C. The thermal conductivity of AP is very large, which is 3~5 times that of general plastics, and the linear expansion coefficient is low, similar to that of PI, and has excellent solder resistance.
(4) Electrical properties AP has excellent electrical properties, with high dielectric constant and low dielectric loss tangent, high dielectric strength, even more than PI and F4, dielectric loss tangent is less affected by the thermometer frequency, and has stable values in a large range.
(5) Environmental performance: AP can be resistant to aliphatic and aromatic solvents, and is not resistant to concentrated sulfuric acid and sodium hydroxide. The radiation resistance is very good, and the mechanical properties remain unchanged after being irradiated by 106Gy cobalt rays. Weather resistance is good, too.
4. Molding processing
Each series of polyphenyl ester resins have different molding processing properties, which can be processed and molded by molding (sintering or hot pressing) and injection molding methods respectively.
5. Scope of application
AP is often used in high-temperature resistant insulating materials and mechanical structure materials by taking advantage of its high heat resistance, high thermal conductivity, low thermal expansion, low friction and abrasion, self-lubricence and creep resistance.