Polymerization by oxidation coupling. I. A study of the oxidation of 2,6‐diphenylphenol to poly(2,6‐diphenyl‐1,4‐phenylene ether)

Abstract

The synthesis of poly(2,6‐diphenyl‐1,4‐phenylene ether), by the oxidative coupling of 2,6‐diphenylphenol has been studied. Procedures were found which demonstrated that polymers of very high molecular weight \documentclass{article}\pagestyle{empty}\begin{document}$ \left( {\overline M _n > 200{\rm 000; }\left[ \eta \right]_{{\rm CHCl}_{\rm 3} }^{25^\circ {\rm C}} > 1.1{\rm }{{{\rm dl}} \mathord{\left/ {\vphantom {{{\rm dl}} g}} \right. \kern-\nulldelimiterspace} g}} \right) $\end{document} could be made with a copper‐amine catalyst system. A low nitrogen‐to‐copper ratio (1 N atom/Cu atom) was necessary to obtain the very high molecular weights under the conditions of these reactions. A variety of amines formed active catalysts; the effectiveness of mono‐ and bis‐ primary, secondary, and tertiary amines were compared. Effects of the type of copper halide, reaction temperature, desiccants, addition rates of 2,6‐di‐phenylphenol, and solvents were also examined. Samples of polymer were isolated at different times during the polymerization. Measurements of viscosity, osmotic pressure, light scattering, gel permeation, phenolic hydroxyl groups, and nitrogen content were made on various samples over a range of intrinsic viscosities of 0.05–0.59 dl/g. A very narrow molecular weight distribution was found for all samples. Hydroxyl endgroup analyses indicated that the concentration of phenolic endgroups per mole of polymer does not change during the polymerization. The presence of some side reactions is indicated by nitrogen analyses. The relationships between the intrinsic viscosity in chloroform at 25°C and M̄n and M̄w are: log [η] = −3.97 + 0.727 log M̄n and log [n] = −3.56 + 0.624 log M̄w.

Recent Progress in Modification of Polyphenylene Oxide for Application in High-Frequency Communication

“…In addition to DMP, the oxidative coupling reaction was also applied to other 2,6-disubstituted phenols, such as 2,6-diphenylphenol (DPP) and 2-allyl-6-methylphenol (AMP), to obtain PPO with a nonregular chemical structure, as shown in Figure 2 . Hay et al synthesized completely aromatic poly(phenyleneoxide)s (P 3 O) using DPP as raw material and bidentate amines as the ligand for the copper salt through the oxidative coupling reaction [ 22 , 23 ]. Different from PPO, which hardly crystallizes and behaves as an amorphous polymer, P 3 O is easy to crystallize, resulting in a high glass transition temperature ( T g ) of 230 °C and melting point ( T m ) of 480 °C (measured by DSC).…”

Self‐Repairing Polymeric Materials

“…However, their stabilization by a hydrogen donor and the presence of Cu (II) secures reactions with each end of the scission chains to form a complex, thus preventing further oxidation. When two end chains are recombined eliminating two protons from both ends, Cu (II) is reduced to Cu (I), and further reacted with molecular O 2 to oxidize again to Cu (II) [21][22][23][24]. Although very promising, these approaches at this point exhibit limited applicability for self-healing composites because the recovery of the cleaved bonds requires elevated temperatures.…”

Poly(phenylene oxide)s

“…34 The pathways for the progression of the oxidized phenols to polymer are described here. They couple to form a quinol ether (4) which enolizes to produce the dimer (5) as shown in equation (3). With 2,6dimethylphenol as the monomer, 2,6-dimethylphenoxy radicals are generated.…”