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Commercial phenyl ether polymers belong to two chemical classes: polyphenyl ethers (PPEs) and polyphenylene oxides (PPOs). The phenoxy groups in the former class of polymers do not contain any substituents whereas those in the latter class contain 2 to 4 alkyl groups on the phenyl ring.
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.
An oil diffusion pump is used to achieve higher vacuum (lower pressure) than is possible by use of positive displacement pumps alone. Although its use has been mainly associated within the high-vacuum range, down to 1 × 10 −9 mbar (1 × 10 −7 Pa), diffusion pumps today can produce pressures approaching 1 × 10 −10 mbar (1 × 10 −8 Pa) when properly used with modern fluids and accessories.
Polyphenyl ether oils are suitable for applications needing high temperature stability, very low volatility, inherent lubricity, and/or radiation resistance. Perfluoropolyether oils are their more chemically inert variant. A eutectic mixture of diphenyl ether (73.5%) and biphenyl (26.5%) is used for its wide temperature range and stability to ...
Ester, ether, and biaryl linkages are present, see below. According to Stéphane Quideau, the term "polyphenol" refers to compounds derived from the shikimate/phenylpropanoid and/or the polyketide pathway, featuring more than one phenolic unit and deprived of nitrogen-based functions. [citation needed]
A cyclic ether and high-boiling solvent (b.p. 101.1 °C). Tetrahydrofuran (THF) A cyclic ether, one of the most polar simple ethers that is used as a solvent. Anisole (methoxybenzene) An aryl ether and a major constituent of the essential oil of anise seed. Crown ethers: Cyclic polyethers that are used as phase transfer catalysts. Polyethylene ...
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Ether groups allow a free rotation of the polymer chains. This leads to a significantly reduced melting point and also improves the mechanical properties by an increased impact strength . [ 7 ] The alkyl groups in bisphenol A act also as a flexible element.