Preparation of Poly(arylene ether pyrimidine)s by Aromatic Nucleophilic Substitution Reactions

Abstract

As part of a continuing effort to prepare novel thermally stable high-performance polymers, poly(arylene ether pyrimidine)s have been prepared with 4,6-bis(4-(trimethylsiloxy)phenyl)pyrimidine and a series of activated bis(aryl fluoride)s using a catalytic amount of cesium fluoride in diphenyl sulfone. These polymers exhibited good thermal stability in both air and helium atmospheres with 10% weight losses in the range 480−540 °C. Moderate to high inherent viscosities (ηinh: 0.40−0.92 dL/g) were recorded, and clear pale yellow flexible fingernail creasable films were solution cast from these samples. A polymer in this series containing a phenylphosphine oxide linkage exhibited good thin film tensile properties and resistance to oxygen plasma. Model reactions with 4,6-bis(4-fluorophenyl)pyrimidine and p-cresol along with studies of this compound's 19F NMR shift values indicated sufficient capacity of the pyrimidine ring to activate aryl fluorides toward polymerization with bis(phenol)s. The pyrimidine bis(aryl fluoride) monomer was used to prepare a series of polymers with selected bis(phenol)s by potassium carbonate-mediated aromatic nucleophilic substitution reactions. One example containing the fluorene moiety exhibited a high inherent viscosity (ηinh: 0.80 dL/g); however, only brittle films could be cast from polymers prepared by this approach.

Synthesis and characterization of novel pyrimidine-containing poly(arylene ether)s

“…7,19 However, the nucleophilic aromatic substitution reaction of 2,4-dichloropyrimidine with bisphenols occurred at the lower temperature of 110 C in the presence of K 2 CO 3 , because 2-and 4-position chlorines were significantly activated by the pyrimidine group. 5 The polymerization reactions proceeded smoothly to high-molecular-weight (M n > 20,000 g mol À1 ) in good yield. Table 1 shows the molecular weights and polydispersity index.…”

“…Poly(arylene ether)s (PAEs) have been widely used as a class of high-performance engineering thermoplastics with the characteristics of excellent mechanical strength, high thermo-oxidative stability, and chemical resistance. [1][2][3][4][5] The preparation of PAEs are typically achieved via nucleophilic aromatic substitution polycondensation reaction between activated aryl halides and bisphenolate ions. Various strongly electron-withdrawing groups, such as sulfonyl, [6][7][8] carbonyl, 9,10 and phosphoryl, 11 have been employed as activating groups to produce high-molecular-weight PAEs.…”

“…The advantages of these polymers are due to the tendency of the heterocycle rings to improve mechanical and adhesive properties as well as glass transition temperature (T g ) of the PAEs while not deteriorating thermal stability and processability. 5 The pyrimidine ring containing nitrogen atoms to each other is deficient of electrons at the 2, 4, and 6 positions due to the electronegativity of the nitrogen atoms, which offers pyrimidine moiety a potential ability to activate aryl halogen substituents toward aromatic nucleophilic displacement reaction.…”

Aromatic Hyperbranched Polymers: Synthesis and Application

“…Under basic conditions of the polycondensation reaction, this fluorine was not only replaced by the phenolate under formation of ether bonds but probably also by the water that was generated by the deprotonation of the hydroxyl groups, which was not removed fast enough by azeotropic distillation, and this finding was supported by a model reaction. Herbert et al showed that activation of the fluorine by the phosphine oxide group in the para position could further accelerate this reaction [196].…”

Facile Synthesis of New Aromatic Polyamides Based on 1,2-Dihydro-2-(4-carboxylphenyl)-4-[4-(4-carboxylphenoxy)-3-methylphenyl]phthalazin-1-one

“…Incorporation of the aromatic heterocycles into the polymer backbone will generally increase mechanical and adhesive properties as well as transition temperature T g of the polymers, while retain thermal stability and processability. 2 We have prepared the aromatic diamine and polyamides containing phthalazinone moiety. [3][4][5] The unique structural feature of the diamines lies in nonsymmetrical and kink non-coplanar conformation of monomer 1.…”