Polyphenylene oxide
Polyphenylene oxide
Polymer of 2,6-dimethylphenol. Also known as polyphenylene oxide. English abbreviation PPO. structure for the glass transition temperature of about 210 ℃, melting temperature of 257 ℃, density 0.96 ~ 1.06 g / cm 3. Practical polyphenylene ether molecular weight of 2 ~ 50,000, crystallinity of about 50%. The most prominent advantage is highly resistant to water and steam. In the 132 ℃ high-pressure steam container processing 200 times, tensile and impact strength did not change significantly, in addition, it also has good dimensional stability, creep, high insulation and other characteristics of the long-term use of the temperature of -127 ~ 120 ℃, no load intermittent work up to 200 ℃, with the general level of thermosetting plastics.
Polyphenylene ether by 2,6-dimethylphenol in the copper salt (such as cuprous chloride) and amine under the action of bonding catalyst, in the air or pure oxygen oxidation coupling polymerization.
Polyphenylene ether is easy to process molding, extrusion, injection and molding can be. Used in the manufacture of medical equipment instead of stainless steel, can withstand steam sterilization, also used for mechanical and electronic parts, insulation materials. Polyphenylene ether and polystyrene **** mixed modifier in the United States trade name Noryl, and can be added 20% to 30% glass fiber, carbon fiber and other enhancements, is an engineering plastics and insulation materials with excellent performance.
Polyphenylene ether physical and chemical properties and uses:
PPO non-toxic, transparent, low relative density, with excellent mechanical strength, stress relaxation resistance, creep resistance, heat resistance, water resistance, water vapor resistance, dimensional stability. In a wide range of temperatures, frequency range of good electrical properties, non-hydrolysis, molding shrinkage is small, flame retardant with self-extinguishing, inorganic acids, alkalis, aromatic hydrocarbons, halogenated hydrocarbons, oils and other poor performance, easy to dissolve or stress cracking, the main drawback is the poor melt fluidity, processing and molding difficulties, the majority of the actual application of the MPPO (PPO **** mixture or alloy), such as modified PPO with PS, can greatly improve the performance of processing If the PS modified PPO, can greatly improve the processing performance, improve the stress cracking resistance and impact performance, reduce costs, just slightly lower heat resistance and gloss. Modified polymers are PS (including HIPS), PA, PTFE, PBT, PPS and a variety of elastomers, polysiloxanes, PS-modified PPO has a long history of large quantities of products, MPPO is the largest amount of general engineering plastics alloy varieties. The larger MPPO varieties are PPO/PS, PPO/PA/elastomer and PPO/PBT/elastomer alloys.PPO and MPPO can be used in injection molding, extrusion, blow molding, molding, foaming and plating, vacuum coating, printing machine processing and other processing methods, due to the high viscosity of the melt, the processing temperature is higher.PPO and MPPO are mainly used in electrical and electronic appliances, automobiles, household appliances, Office equipment and industrial machinery, etc. Using MPPO heat resistance, impact resistance, dimensional stability, scuffing resistance, peeling resistance, paintability and electrical properties, it is used to make automobile dashboards, radiator grills, speaker grills, consoles, fuse boxes, relay boxes, connectors, wheel covers; it is widely used in the electronic and electrical industry to make connectors, coil winding spools, switch relays, tuning equipment, large-scale Electronic display, variable capacitors, battery accessories, microphones and other parts. Household appliances used in television sets, cameras, videotapes, tape recorders, air conditioners, heaters, rice cookers and other parts. Can be used as copy machines, computer systems, printers, fax machines and other external parts and components. In addition, we can make the shells and parts of cameras, timers, water pumps, blowers, silent gears, pipes, valve bodies, surgical instruments, sterilizers and other medical appliance parts. Large blow molding can be done to make large automotive parts such as flow blocker, bumper, low-foam molding is suitable for the production of high rigidity, dimensional stability, excellent acoustic absorption, the internal structure of complex large-scale products, such as a variety of machine shells, bases, internal brackets, the degree of freedom of design, product lightweight.