First Structural Analysis of a Naphthalene-Based Poly(ether ketone): Crystal and Molecular Simulation from X-ray Powder Data and Diffraction Modeling

Polycondensation of 2,6-dihydroxynaphthalene with 4,4‘-bis(4‘ ‘-fluorobenzoyl)biphenyl affords a novel, semicrystalline poly(ether ketone) with a melting point of 406 °C and glass transition temperature (onset) of 168 °C. Molecular modeling and diffraction-simulation studies of this polymer, coupled with data from the single-crystal structure of an oligomer model, have enabled the crystal and molecular structure of the polymer to be determined from X-ray powder data. This structure the first for any naphthalene-containing poly(ether ketone) is fully ordered, in monoclinic space group P 2 1 / b, with two chains per unit cell. Rietveld refinement against the experimental powder data gave a final agreement factor ( R wp ) of 6.7%.