Polyoxyxylene was produced by General Electric A.S. Hay in 1956. It uses cuprous chloride as a catalyst to oxidatively couple 2,6-dimethylphenol into polyoxyxylene. , and published in 1964, named PPO.
Polyoxyxylene is one of the cheaper high-temperature plastics, but it is difficult to make and its impact resistance and heat resistance will decrease over time. Mixing polyoxyxylene and polystyrene can improve this shortcoming. In the 1960s, modified polyoxyxylene was introduced under the trade name Noryl. The main ones commonly used on the market are modified polyphenylene ether (Modified Polyphenylene Oxide), referred to as MPPO, or MPPE (Modified Polypheylene ether). 1. It is white particles. It has good overall performance and can be used in 120-degree steam. It has good electrical insulation and low water absorption, but it has a tendency of stress cracking. Modified polyphenylene ether eliminates stress cracking. 2. It has outstanding electrical insulation and water resistance, good wear resistance and electrical properties, and good dimensional stability. Its dielectric properties rank first among plastics. 3. MPPO is a modified material made by mixing PPO and HIPS. All the materials on the market are this kind of material.
4. It has high heat resistance, with a glass transition temperature of 211 degrees and a melting point of 268 degrees. It has a tendency to decompose when heated to 330 degrees. The higher the content of PPO, the better the heat resistance. Thermal distortion temperature Up to 190 degrees. 5. It has good flame retardancy, is self-interesting, and has moderate flammability after being mixed with HIPS. Lightweight, non-toxic and can be used in the food and pharmaceutical industries. It has poor light resistance and will change color if used in the sun for a long time. 6. It can be mixed and modified with ABS, HDPE, PPS, PA, HIPS, glass fiber, etc. Characteristics of PPO plastic raw materials
A. PPO plastic raw materials are non-toxic, transparent, have low relative density, and have excellent mechanical strength, stress relaxation resistance, creep resistance, heat resistance, water resistance, and water vapor resistance. , dimensional stability.
B. Good electrical properties within a wide temperature and frequency range, no hydrolysis, small mold shrinkage, flame retardant, self-extinguishing, resistant to inorganic acids, alkali, aromatic hydrocarbons, and halogenated hydrocarbons , oil, etc. have poor performance and are prone to swelling or stress cracking.
C. It has the advantages of high rigidity, high heat resistance, flame retardancy, high strength and excellent electrical properties. D. Polyphenylene ether also has the advantages of wear resistance, non-toxicity, and pollution resistance.
E. The dielectric constant and dielectric loss of PPO plastic raw materials are one of the smallest among engineering plastics. They are almost not affected by temperature and humidity and can be used in low, medium and high frequency electric fields. .
F. The load deformation temperature of PPO can reach over 190℃, and the embrittlement temperature is -170℃. G. The main disadvantage is poor melt fluidity and difficulty in processing and forming. PPO is non-toxic, transparent, has a low relative density, and has excellent mechanical strength, stress relaxation resistance, creep resistance, heat resistance, water resistance, water vapor resistance, and dimensional stability. It has good electrical properties in a wide temperature and frequency range. The main disadvantages are poor melt fluidity and difficulty in processing and molding. Most practical applications are MPPO (PPO mixture or alloy). If PPO is modified with PS, it can be greatly improved. Processing performance, improved stress crack resistance and impact performance, reduced costs, only slightly reduced heat resistance and gloss. Modified polymers include PS (including HIPS), PA, PTFE, PBT, PPS and various elastomers, polysiloxane, PS modified PPO has a long history and a large number of products. MPPO is the most widely used general engineering plastic alloy variety. . The larger MPPO varieties include PPO/PS, PPO/PA/elastomer and PPO/PBT/elastomer alloy. PPO and MPPO can adopt various processing methods such as injection molding, extrusion, blow molding, molding, foaming and electroplating, vacuum coating, printing machine processing, etc. Due to the high melt viscosity, the processing temperature is high.
PPO and MPPO are mainly used in electronic appliances, automobiles, household appliances, office equipment and industrial machinery, etc., taking advantage of MPPO's heat resistance, impact resistance, dimensional stability, scratch resistance, peeling resistance, Paintability and electrical properties, used to make automobile dashboards, radiator grilles, speaker grilles, consoles, fuse boxes, relay boxes, connectors, wheel covers; widely used in the electronic and electrical industry to manufacture connectors, coil windings Bobbins, switching relays, tuning equipment, large electronic displays, variable capacitors, battery accessories, microphones and other components. Used in household appliances such as televisions, cameras, video tapes, tape recorders, air conditioners, heaters, rice cookers and other parts. It can be used as external parts and components for copiers, computer systems, printers, fax machines, etc. In addition, it can be used as housings and parts of cameras, timers, water pumps, blowers, silent gears, pipes, valve bodies, surgical instruments, sterilizers and other medical equipment parts. Large-scale blow molding can be used to produce large automobile parts such as spoilers and bumpers. Low-foam molding is suitable for producing large-scale products with high rigidity, dimensional stability, excellent sound absorption, and complex internal structures, such as various machine casings, bases, and interiors. The bracket has a large degree of design freedom and the product is lightweight. A method for preparing polyphenylene ether, including: contacting a polyphenylene ether solution obtained by polymerization in the presence of a water-insoluble polymerization solvent and a catalyst with a chelating agent aqueous solution to terminate the polymerization reaction and deactivate the catalyst; Then add a water-soluble solvent of insoluble polyphenylene ether to precipitate the polyphenylene ether, and separate and recover the precipitated polyphenylene ether;
Among them (a) polyphenylene ether solution and chelating agent The aqueous solution is mixed and contacted, and maintained at 50 to 120°C for 10 to 180 minutes;
Among them (b) the mixture after separation and recovery of polyphenylene ether contains a water-insoluble polymerization solvent and a water-soluble poorly soluble polymer Solvent of phenylene ether, add this mixture to water to extract the solvent of water-soluble and poorly soluble polyphenylene ether, so that the solvent of water-soluble and poorly soluble polyphenylene ether is extracted into the water phase and separated from the polymerization solvent;
Wherein (c) the solvent of the water-soluble and poorly soluble polyphenylene ether is separated and removed from the aqueous phase by distillation, and all or part of the remaining water is circulated for contact with the filtrate after the separation of the polyphenylene ether, The remaining aqueous phase contains 1% by weight or less of high boiling point organic matter. It includes two parts: polymerization and post-treatment: first add a certain amount of copper ammonia complex catalyst to the polymerization reactor, bubble oxygen into it, and then gradually add 2,6-dimethylphenol and ethanol solution to perform oxidative coupling polymerization. A polymer is obtained. Post-processing is to centrifuge the polymer, wash it with ethanol solution containing 30% sulfuric acid, then soak it in dilute alkali solution, wash it with water, dry it and granulate it to obtain the granular resin of polyphenylene ether.
2,6-diphenylphenol can also be used as the monomer. The resulting polyphenylene ether has better thermal stability and has been used to manufacture high-temperature resistant films and insulation products.
In order to improve the molding performance and reduce costs, polyphenylene ether can be modified by mixing methods. Modified polyphenylene ether has low cost and can compete with ABS resin in market price, and is widely used. To replace bronze or brass to make various mechanical parts and pipes, etc. R36 is irritating to eyes.
R37 stimulates the respiratory system.
R38 is irritating to the skin.