Synthesis and characterization of soluble copoly(arylene ether ketone sulfone)s bearing xanthene moiety in the main chain

Abstract

Several new poly(arylene ether ketone sulfone) (PEKS) copolymers containing xanthene moiety in the main chain were prepared by direct solution polycondensation reaction of 1,4-bis(4-fluorobenzoyl)benzene with varying mole ratios of 9,9-bis(4-hydroxyphenyl)xanthene and 4,4′-sulfonyldiphenol using sulfolane as solvent in the presence of anhydrous potassium carbonate. The introduction of xanthene and sulfone groups into the polymer chain resulted in an improvement in solubility of the polymers in common organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethyl acetamide, sulfolane, pyridine, chloroform, and tetrahydrofuran. Thermal analysis revealed that the copolymers exhibited high glass transition temperatures (T_gs) of 208–221°C and excellent thermal stability associated with 5% weight loss temperatures ranging from 490°C to 521°C and 62–66% residual weight at 650°C under nitrogen atmosphere. All copolymers were amorphous and their solubility increased with an increase of sulfone content in the polymer backbone, while the T_gs and overall thermal stability appeared to decrease slightly. This new kind of xanthene-containing PEKS copolymers may be considered a good candidate for using as high-performance structural materials.