Linear soluble polybenzyls

Abstract

Linear soluble polybenzyls, although deceptively simple in structure, have been strangely elusive. We report for the first time the synthesis of perfectly linear soluble polybenzyls by the polycondensation of 1,2,4,5-tetrasubstituted benzenes with formaldehyde using CHCl 3 /trifluoroacetic acid (TFA) as the medium, wherein TFA served both as an acidic catalyst as well as a cosolvent. The number-average molecular weights (M n 's) of the polymers, as determined by gel permeation chromatography, varied from about 1000 to 37,000, depending on the nature of the substituent on the benzene ring; M n was highest when all four substituents were alkoxy groups and was lowest when they were all alkyl groups. This correlated well with susceptibility of the aromatic ring toward electrophilic aromatic substitution, which is the underlying polymerization mechanism. Differential scanning calorimetry of the polymers showed that most of the samples were amorphous with glass-transition temperatures ranging from about Ϫ80°to ϩ80°C, whereas a few that were either symmetrically substituted or possessed a long alkyl substituent were partially crystalline. Preliminary studies suggested that the methylene unit linking the phenyl rings in these polybenzyls could be readily oxidized to generate conjugated polymers that may be perceived as carbon analogues of polyaniline-poly(arylmethine)s.

Synthesis of High Molar Mass Poly(phenylene methylene) Catalyzed by Tungsten(II) Compounds

“…Poly(phenylene methylene) (PPM) consists of phenylene rings bridged by a methylene unit (Figure 1a). PPM is completely amorphous [1,2,3,4,5] and possesses an exceptional combination of high thermal stability (onset of the decomposition temperature at 450 °C–470 °C) [1,2,3,6,7], and blue fluorescence in solution as well as in the solid state, with an unusually long photoluminescence lifetime (about 8 ns) and a high photoluminescence quantum efficiency compared to other polymers (41% in solid state) [7,8]. The fluorescence, however, is unexpected since in organic polymers this property is commonly a consequence of extended π–delocalization while the phenylene rings in PPM are electronically separated by methylene units.…”

Poly(Phenylene Methylene): A Multifunctional Material for Thermally Stable, Hydrophobic, Fluorescent, Corrosion-Protective Coatings

“…Further, PPM is structurally similar to phenol resins but possesses higher thermal stability [14]. Accordingly, PPM has been proposed as a valuable material for coatings [15][16][17][18]. In the panorama of protective coatings against corrosion of polymers with similar application methods and protection mechanism of PPM, there are epoxy resins, especially FBE formulations, and epoxy-polyaniline systems.…”

Processing of the Multifunctional Polymer Poly(phenylene methylene) into Fibers, Films, Foams, and Microspheres

“…PPM has been shown to be active in corrosion protection and has been proposed for various applications from fire‐resistant fibers to protective coatings, and from semiconducting devices to packaging …”