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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.
Polymerization of ethylene oxide is an exothermic process. Overheating or contaminating ethylene oxide with catalysts, such as alkalis or metal oxides, can lead to runaway polymerization, which can end in an explosion after a few hours. Polyethylene oxide, or high-molecular-weight polyethylene glycol, is synthesized by suspension polymerization.
The structure of the repeating unit of PPP Space-filling model of a short section of PPP. Poly(p-phenylene) (PPP) is made of repeating p-phenylene units, which act as the precursor to a conducting polymer of the rigid-rod polymer family.
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.
Polyphenols are also found in animals. In arthropods, such as insects, [36] and crustaceans [37] polyphenols play a role in epicuticle hardening (sclerotization). The hardening of the cuticle is due to the presence of a polyphenol oxidase. [38] In crustaceans, there is a second oxidase activity leading to cuticle pigmentation. [39]
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 .
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 ...