PPO material from SIKO
Polyphenylene oxide or polyethylene ether Also known as polyphenylene oxide or polyphenylene ether, is a high temperature resistant thermoplastic resin.
Characteristics and Applications
PPO is a thermoplastic engineering plastic with excellent comprehensive performance, outstanding electrical insulation and water resistance, and good dimensional stability.
1, dielectric properties of engineering plastics first
PPO resin molecular structure without strong polar groups, stable electrical properties, can maintain good electrical properties in a wide range of temperature and frequency.
① Dielectric constant: 2.6-2.8 is the smallest in engineering plastics ② Tangent of dielectric loss Angle: 0.008-0.0042 (almost not affected by temperature, humidity and frequency) ③ Volume resistivity: 1016 is the highest in engineering plastics
2, good mechanical and thermal properties of PPO molecular chain, containing a large number of aromatic ring structure, molecular chain sensitivity is strong, resin mechanical strength is high, excellent creep resistance, temperature change is very small. PPO has high heat resistance, glass transition temperature up to 211℃, melting point 268℃.
3, excellent water resistance PPO is non-crystalline resin, in the usual temperature range, less molecular movement, no large polar groups in the main chain, dipole moment does not occur pole, water resistance is very good, is the lowest water absorption rate of engineering plastics varieties. Its physical properties still have little degradation after soaking in hot water for a long time.
4, The oxygen index of self-extinguishing PPO is 29, which is self-extinguishing material, and the oxygen index of high impact polyethylene is 17, which is inflammable material. The combination of the two is of moderate flammability. When making flame retardant PPO, there is no need to add halogen flame retardant, adding phosphorus-containing flame retardant dose can reach UL94 standard. Reduce pollution to the environment.
5, low shrinkage rate, good dimensional stability; Non-toxic, low density 6, dielectric resistance and light resistance PPO acid, alkali and detergent and other basic corrosion, under the condition of stress, mineral oil and ketone, ester solvents will produce stress cracking; Organic solvents such as aliphatic hydrocarbons, halogenated aliphatic hydrocarbons and aromatic hydrocarbons can melt and dissolve.
PPO weakness is poor light resistance, long time under sunlight or fluorescent lamp use produces discoloration, color yellow, the reason is that ultraviolet light can make the chain of aromatic ether split. How to improve the light resistance of PPO becomes a topic.
The performance of PPO determines the field and scope of application:
①MPPO density is small, easy to process, thermal deformation temperature in 90-175℃, there are different specifications of goods, good dimensional stability, suitable for the manufacture of office equipment, household appliances, computer boxes, chassis and precision parts.
② MPPO dielectric constant and dielectric loss Angle tangent in the five general engineering plastics in the lowest, that is, the best insulation, and good heat resistance, suitable for the electrical industry. Suitable for making electrical insulating parts, such as coil frame, tube holder, control shaft, transformer shield sleeve, relay box, insulating pillar and so on, which are used in wet and loaded conditions.
③ MPPO has good water resistance and heat resistance, which is suitable for making water meters, water pumps and yarn tubes used in textile factories that need durable consumer goods for cooking. The yarn tubes made of MPPO have long service life.
④ The dielectric constant and dielectric loss Angle tangent of MPPO are not affected by temperature and cycle number in engineering plastics, and have good heat resistance and dimensional stability, which are suitable for electronic industry.