2,6-dimethyl-l,4-phenylene ether

The substituents in the 2- and 6-positions must not exceed a certain geometrical size. Otherwise, instead of regular -0-C- coupling leading to the po-ly(phenylene ether)s, there is simply a -C-C- coupling of the monomers to form diphenylquinones. This reaction is favored by higher temperatures. The pale-yellow coloration of poly(-2,6-dimethyl-l,4-phenylene ether) may be caused by the presence of quinones. 

A.B. Boscoletto, M. Checchin, L. Milan, P. Pannocchia, M. Tavan, G. Camino, and M.P. Luda, Combustion and fire retardance of poly-(2,6-dimethyl-l,4-phenylene ether)-high-impact polystyrene blends. II. Chemical aspects,/. Appl. Polym. Sci., 67(13) 2231-2244,1998. 

Ruckdaschel H, Rausch J, Sandler JKW, Altstadt V, Schmalz H, Muller AHE (2008) Correlation of the melt rheological properties with the foaming behavior of immiscible blends of poly(2,6-dimethyl-l,4-phenylene ether) and poly (styrene-co-acrylonitrile). Polym Eng Sci 48 2111-2125... 

Auschra C, Stadler R (1993) Polymer alloys based on poly(2,6-dimethyl-l,4-phenylene ether) and poly(styrene-co-acrylonitrile) using poly(styrene-f>-(ethylene-co-butylene)-b-methyl methacrylate) triblock copolymers as compatibilizers. Macromolecules 26 6364-6377... 

Goldel A, Ruckdaschel H, Muller AHE, Potschke P, Altstadt V (2008) Controlling the phase morphology of immiscible poly(2,6-dimethyl-l,4-phenylene ether)/poly(styrene-coacrylonitrile) blends via addition of polystyrene. e-Polymers 151... 

The ability to polymerize readily via selective oxidation utilizing the abundant and cheap oxidant 02 often represents a desirable low-cost method for upgrading the value of a raw material. The most successful example is the oxidative polymerization of 2,6-dimethylphenol to yield poly(2,6-dimethyl-l,4-phenylene ether) with copper-amine catalysts under an 02 atmosphere at room temperature. Thiophenol also has a labile hydrogen but is rapidly oxidized to yield thermodynamically stable diphenyl disulfide. This formation is based on the more facilitated formation of S—S bond through radical coupling [82] in comparison with the formation of C—S—C bond through the coupling with the other molecules in the para position (Eq. 9). 

An Sjuyl-type (S l ) mechanism has been proposed in the synthesis of poly(2,6-dimethyl-l,4-phenylene ether) through the anion-radical polymerization of 4-bromo-2,6-dimethylphenoxide ions (204) under phase-transfer catalysed conditions269. Ions 204 are oxidized to give an oxygen radical 205. The propagation consists of the radical nucleophilic substitution by 205 at the ipso position of the bromine in 204 (equation 144). The anion-radical 206 thus formed eliminates a bromide ion to form a dimer phenoxy radical 207 (equation 145). A polymeric phenoxy radical results by continuation of this radical nucleophilic substitution. 

PB PBI PBMA PBO PBT(H) PBTP PC PCHMA PCTFE PDAP PDMS PE PEHD PELD PEMD PEC PEEK PEG PEI PEK PEN PEO PES PET PF PI PIB PMA PMMA PMI PMP POB POM PP PPE PPP PPPE PPQ PPS PPSU PS PSU PTFE PTMT PU PUR Poly(n.butylene) Poly(benzimidazole) Poly(n.butyl methacrylate) Poly(benzoxazole) Poly(benzthiazole) Poly(butylene glycol terephthalate) Polycarbonate Poly(cyclohexyl methacrylate) Poly(chloro-trifluoro ethylene) Poly(diallyl phthalate) Poly(dimethyl siloxane) Polyethylene High density polyethylene Low density polyethylene Medium density polyethylene Chlorinated polyethylene Poly-ether-ether ketone poly(ethylene glycol) Poly-ether-imide Poly-ether ketone Poly(ethylene-2,6-naphthalene dicarboxylate) Poly(ethylene oxide) Poly-ether sulfone Poly(ethylene terephthalate) Phenol formaldehyde resin Polyimide Polyisobutylene Poly(methyl acrylate) Poly(methyl methacrylate) Poly(methacryl imide) Poly(methylpentene) Poly(hydroxy-benzoate) Polyoxymethylene = polyacetal = polyformaldehyde Polypropylene Poly (2,6-dimethyl-l,4-phenylene ether) = Poly(phenylene oxide) Polyp araphenylene Poly(2,6-diphenyl-l,4-phenylene ether) Poly(phenyl quinoxaline) Polyphenylene sulfide, polysulfide Polyphenylene sulfone Polystyrene Polysulfone Poly(tetrafluoroethylene) Poly(tetramethylene terephthalate) Polyurethane Polyurethane rubber... 

Phenols are oxidized by NaBiO3 to polyphenylene oxides, quinones, or cyclohexa-2,4-dienone derivatives, depending on the substituents and the reaction conditions [263]. For example, 2,6-xylenol is oxidized in AcOH to afford a mixture of cyclohexa-dienone and diphenoquinone derivatives (Scheme 14.123) [264] and is oxidatively polymerized in benzene under reflux to give poly(2,6-dimethyl-l,4-phenylene) ether (Scheme 14.124) [265]. Substituted anilines and a poly(phenylene oxide) are oxidatively depolymerized by NaBiO, to afford the corresponding anils [266]. Nal iO, oxidizes olefins to vicinal hydroxy acetates or diacetates in low to moderate yield [267]. Polycyclic aromatic hydrocarbons bearing a benzylic methylene group are converted to aromatic ketones in AcOH under reflux (Scheme 14.125) [268]. 

Kim HC, Nam KH, Jo WH. The effect of a styrene-methyl methacrylate block copolymer on the morphological, rheological and mechanical properties of poly(2-6-dimethyl-l,4-phenylene ether) (PPE) and poly(hydroxyether of bis-phenol A) (phenoxy) blends. Polymer 1993 34 4043-4051. 

Chalk, Hay, and Hoogenboom (6, 7) using the same complex, reported lithiating poly(2,6-dimethyl-l,4-phenylene) ether and poly(2,6-diphenyl-1,4-phenylene) ether. The lithiation was done both at room temperature over a long time and at reflux for a shorter time. They reported catalyst efficiency of 17% as determined by the lithium content in the polymer. They attributed the low level of lithiation to the attack on THF by the metalating complex. 

Tetramethvlbisphenol A Polycarbonate. A new polycarbonate has been introduced in Europe by Bayer AG (Figure 6). It is based on tetramethyIbisphenol A (TMBPA). The monomer is produced by condensing two molecules of 2,6-dimethylphenol, which is the monomer for General Electric s poly(2,6-dimethyl-l,4-phenylene ether) polymers, with acetone. The polycarbonate from tetramethylbisphenol A resembles the dimethylphenylene ether polymers in their unusually high T 207 C for the polycarbonate and 215 °C for the polyether. 

Oudhuis and ten Brinke [1992] have addressed these points by examining the aging of blends of PS with poly(2,6-dimethyl-l,4-phenylene ether), PPE, where now both components are relatively rigid, although there is still about 100°C difference between the T values. These authors found that... 

Poly(2,6-dimethyl-l,4-phenylene ether) 298 18.1 Polypropylene, syndiotactic 298 17.6... 

PPO , that is, poly-2,6-dimethyl-l,4-phenylene ether or PPE, is a high-performance thermoplastic obtained by polymerization of DMP, which exhibits particular physical properties such as high thermal stability, elevated mechanical strength, and excellent hydrolytic stability (Table 7.1) [14]. 

In order to meet increasing performance demands for electret applications, polymer electret blends are being explored. Lovera et al. have recently reported on tailored polymer electrets based on poly(2,6-dimethyl-l,4-phenylene ether) (PPE) and its blends with polystyrene (PS) [98]. They obtained good electret performance with neat PPE and showed that it could be improved by blending with PS. 

Jain, R. K., Simha R., and Zoller, P., Theoretical equation of state of polymer blends the poly(2,6-dimethyl-l,4-phenylene ether)-polyst5n ene pair, J. Polym. Sci. Polym. Phys. Ed., 20, 1399-1408 (1982). 

FT-Raman spectra were determined for atactic PS, poly(2,6-dimethyl-l,4-phenylene ether) (PPE) and then-blends. Composition-dependent spectral variations of the blends were analysed using generalised 2-D correlation spectroscopy to study the conformational changes and blend interactions. The 2D synchronous correlation analysis was able to discriminate between the bands of PS and those of PPE, and was able to detect bands that were not readily identifiable in ID spectra. The main chain conformation of PS undergoes a drastic change on blending with PPE (57). 

No.19,21st Sept.1999, p.6307-18 TWO-DIMENSIONAL FOURIER TRANSFORM RAMAN CORRELATION SPECTROSCOPY STUDIES OF POLYMER BLENDS CONFORMATIONAL CHANGES AND SPECIFIC INTERACTIONS IN BLENDS OF ATACTIC POLYSTYRENE AND POLY(2,6-DIMETHYL-l,4-PHENYLENE ETHER)... 

Delsman ER, Schoenmakers GJ. High molecular weight poly(2,6-dimethyl-l,4-phenylene ether) and process therefor US Patent 8 507 636, assigned to Sabic Innovative Plastics IP B.V., NL 2013. 

KimNC, Kim YT, Nam SW, Jeon BS, Kim YJ. Synthesis of poly(2,6-dimethyl-l,4-phenylene ether) with controlled molecular weight via suspension polymerization catalyzed by amine-copper (I) complexes under various reaction conditions. Polym Bull 2013 70(l) 23-33. 

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