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Poly(p-phenylene oxide) (PPO), poly(p-phenylene ether) (PPE), poly(oxy-2,6-dimethyl-1,4-phenylene), often referred to simply as polyphenylene oxide, is a high-temperature thermoplastic with the general formula (C 8 H 8 O) n. It is rarely used in its pure form due to difficulties in processing.
Physical properties of a particular PPE depend upon the number of aromatic rings, their substitution pattern, and whether it is an ether or a thioether. In the case of products of mixed structures, properties are hard to predict from only the structural features; hence, they must be determined via measurement.
Polyphenylene oxide (PPO), which is obtained from the free-radical, step-growth oxidative coupling polymerization of 2,6-xylenol, has many attractive properties such as high heat distortion and impact strength, chemical stability to mineral and organic acids, and low water absorption. PPO is difficult to process, and hence the commercial resin ...
Poly(2,6-diphenylphenylene oxide) is a low bleeding material with a low level of impurities, and has a high thermal stability (up to 350 °C). Before use poly(2,6-diphenylphenylene oxide) should be thermally conditioned with a high purity gas at elevated temperatures to remove any residual components.
[2] [85] [86] [87] Research is limited on the effect of this inhibition on iron status. [ 88 ] Metabolism of polyphenols can result in flavonoid-drug interactions, such as in grapefruit–drug interactions , which involves inhibition of the liver enzyme , CYP3A4 , likely by grapefruit furanocoumarins , a class of polyphenol.
One exception to the rule of incompatibility is the material Noryl, where polystyrene and polyphenylene oxide or PPO form a continuous blend with one another. Schematic crystalline block copolymer Other TPEs have crystalline domains where one kind of block co-crystallizes with other block in adjacent chains, such as in copolyester rubbers ...
The NORYL family of modified resins consists of amorphous blends of polyphenylene oxides (PPO) or polyphenylene ether (PPE) resins with polystyrene.They combine the inherent benefits of PPE resin (affordable high heat resistance, good electrical insulation properties, excellent hydrolytic stability and the ability to use non-halogen fire retardant packages), with excellent dimensional ...
Polyphenylene sulfide (PPS) is an organic polymer consisting of aromatic rings linked by sulfides. Synthetic fiber and textiles derived from this polymer resist chemical and thermal attack. PPS is used in filter fabric for coal boilers , papermaking felts , electrical insulation , film capacitors , specialty membranes , gaskets , and packings .