Chemical name of polyphenylene ether is poly 2,6-dimethyl 1,4-phenylene ether, PPO (polyphenylene oxide) or PPE (polyoheylene ether) for short, also known as polyphenylene oxide or polyphenylene ether. It is a kind of high temperature resistant thermoplastic resin.
Modified polyphene oxide (modified polyphene oxide), referred to as PPO or MPPE (modified polyphene ether), is mainly used in the market. Due to custom, p-polyphenylene ether and its modified blend polymers are called PPO or PPE.

 

PPO is a thermoplastic engineering plastic with excellent comprehensive properties, outstanding electrical insulation, excellent water resistance, and good dimensional stability.
1. Dielectric performance ranks first among engineering plastics
There are no strong polar groups in molecular structure of PPO resin, and its electrical properties are stable. It can maintain good electrical properties in a wide range of temperature and frequency.① Dielectric constant: 2.6-2.8 is the smallest among engineering plastics ② Dielectric loss tangent: 0.008-0.0042 (hardly affected by temperature, humidity and frequency) ③ Volume resistivity: 1016 is the highest among engineering plastics.
2. Good mechanical and thermal properties: PPO molecular chain contains a large number of aromatic ring structures, molecular chain is more sensitive, resin has higher mechanical strength, excellent creep resistance, and has little effect on temperature changes. PPO has high heat resistance, glass transition temperature is as high as 211℃, and melting point is 268℃.
3. Excellent water resistance PPO is a non-crystalline resin. In usual temperature range, there is little molecular movement, no large polar groups in main chain, no polarization of dipole moment, very good water resistance, and the lowest water absorption rate among engineering plastics. Physical properties of immersion in hot water for a long time still have little degradation.
4. Good flame retardancy and self-extinguishing. Oxygen index of PPO is 29, which is a self-extinguishing material, and oxygen index of high-impact polyethylene is 17 is a flammable material. Combination of the two is moderately flammable. When manufacturing flame retardant grade PPO, there is no need to add halogen flame retardant, amount of phosphorus-containing flame retardant can reach UL94 standard, reducing environmental pollution.
5. Low shrinkage rate, good dimensional stability; non-toxic, low density 6. Medium and light resistance. PPO is basically not corrosive to acids, alkalis and detergents. Under stress, mineral oil, ketones, and ester solvents will cause stress cracking; for organic solvents such as aliphatic hydrocarbons, halogenated aliphatic hydrocarbons and aromatic hydrocarbons, it will melt and dissolve.　　
Weak point of PPO is its poor light resistance, discoloration and yellowish color when used under sunlight or fluorescent light for a long time. Reason is that ultraviolet rays can cause chain combination of aromatic ether to split. How to improve light resistance of PPO has become a problem.　　

① MPPO has low density and is easy to process. Heat distortion temperature is 90-175℃. There are products of different specifications and good dimensional stability. It is suitable for manufacturing office equipment, household appliances, computer cabinets, chassis and precision parts.
② MPPO's dielectric constant and dielectric loss tangent are the lowest among five general engineering plastics, that is, insulation is the best, it has good heat resistance, which is suitable for electrical industry. It is suitable for production of electrical insulating parts used under damp and load conditions, such as coil bobbin, tube socket, control shaft, transformer shielding sleeve, relay box, insulating pillar, etc.
③ MPPO has good water resistance and heat resistance. It is suitable for making water meters, water pumps, and spinning tubes used in textile mills that require durable consumer goods for cooking. Tubes made of MPPO have a long service life.
④ Dielectric constant and dielectric loss tangent of MPPO is not affected by temperature and frequency in engineering plastics, has good heat resistance and dimensional stability, which is suitable for electronics industry.
⑤ Due to development of electronics industry and communications industry, mobile phones, portable computers, high-performance cameras, camcorders, etc. all require lithium-ion batteries. Therefore, lithium-ion battery market has great development prospects. Packaging materials of organic electrolyte for lithium-ion batteries used to be used in the past. ABS or PC, MPPO for batteries has recently been developed abroad, its performance is better than the former two.
⑥ MPPO has a wide range of uses in automotive industry, such as instrument panels, protective bars, etc., PPO and PA alloys, especially high-impact specifications and varieties are used for exterior decoration parts faster.
⑦ Chemically modified polyphenylene ether can be used to make corrosion-resistant equipment. Its resistance to hydrolysis is particularly good, it is also resistant to acids and alkalis, is inexpensive to dissolve in aromatic hydrocarbons and chlorinated hydrocarbons.
⑧ For medical equipment, it can replace stainless steel and other metals in hot water tanks, exhaust fan mixing and packing valves.