Synthesis and Chemical, Physical, and Optical Properties of 9,9-Diarylfluorene-Based Poly(ether−ether−ketone)

Abstract

Fluorene-based poly(ether-ether-ketone) (F-PEEK) was designed and synthesized by reacting a 9,9-diarylfluorene-containing biphenol and a naphthalene-containing dihaloarene. High molecular weight F-PEEK (M w > 270 000; M n ∼ 55 000) was obtained in quantitative yields by the two-step polycondensation of 9,9-bis-(4-hydroxy-3-methylphenyl)fluorene and 1,5-bis(4-fluorobenzoyl)-2,6-dimethylnaphthalene in the presence of cesium carbonate in diphenyl sulfone at 165 °C and then 220 °C. The chemical, physical, and optical properties of F-PEEK were evaluated. Good solubility of F-PEEK in ordinary organic solvents such as THF and chloroform was confirmed. F-PEEK exhibited a high refractive index of 1.64 at 589 nm, whereas it showed a much lower birefringence value than a polycarbonate or a polyester. F-PEEK was amorphous and transparent at room temperature. The transmittance of F-PEEK in film state was over 80% in the visible region. These optical properties were probably related to the cardo structure of the fluorene moiety placed on the main chain. No phase transition except for T g was confirmed in the DSC analysis. F-PEEK displayed a high storage modulus (E′ ) 2.93 GPa) and glass transition temperature (280 °C) in comparison with commercially available poly(ether-ether-ketone) (PEEK, E′ ) 1.73 GPa and T g 169 °C). The high modulus of F-PEEK was derived unambiguously from both the fluorene and naphthalene skeletons.

Synthesis of Cardo Based Poly(arylene ether)s for Flexible Plastic Substrates and Their Properties

“…[6][7][8] In this paper, we explore new PAEs with both transparency and improved thermal properties.…”

“…In particular, cardo typed aromatic diols, which contain a bulky group such as fluorene, 6,8 or adamantane [9][10][11] moiety in the center of the monomer structure, have been widely employed to produce corresponding PAEs which show good solubility and high optical transparency without any decrease of thermal stability. It also has been reported that the incorporation of trifluoromethyl, sulfonyl, ketone, and/or ether moieties between benzene rings activates aromatic halide monomers and consequently accelerates a nucleophilic displacement reaction by generating aromatic diphenolate ions from the aromatic diols and results in a high molecular weight polymer during the polycondensation.…”

“…The GPC chromatogram of the new PAEs showed single, relatively, narrow peaks (polydispersity index of 1.37 to 1.52), indicating that no branching reactions occurred during the polymerization. 6,8 This is a noticeable improvement over other kinds of cardo typed PAEs which have wide molecular weight distributions.…”

Poly(vinylspirobifluorene): Synthesis and Properties of a Novel Styrenic Polymer

“…The ''cardo'' polymers have recently generated particular interest due to their characteristic properties such as high refractive index, 1 low birefringence, 1 high solubility, high thermal stability, and fine dispersing ability toward fillers.…”

“…The high thermal stability of 5 seems to come from the presence of SBF moieties in accordance with the previously reported results. 1,2 It should be noted, however, that polymer 5 possesses the SBF groups in a side chain not in the main chain. This is the first example of the side chain type SBF polymer, and thereby we can conclude that the incorporation of the SBF group into polymer contributes to enhancement of its thermal stability independent of whether it is placed on the main chain or side chain, probably owing to the effective intramolecular packing to disturb a random walk.…”