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.