Synthesis of sulfone-containing polyphosphates: low temperature solution polycondensation of bisphenol S analogues and aryl phosphorodichlorides

Abstract

This paper describes the synthesis of new sulfone-containing polyphosphates from the reaction of various aryl phosphorodichlorides with bisphenol S (BPS) and its analogues in a chlorinated hydrocarbon solvent under low temperature conditions. The polyphosphates obtained were characterized by IR, 13C and 31P NMR spectra, elemental analysis, inherent viscosity, TGA, DSC, X-ray diffraction, solubility, LOI, contact angle and molar mass measurement. All the polyphosphates had high yields and the inherent viscosities were in the range of 0.12–0.44 dl g −1. Almost all the polyphosphates, except that obtained from the bis[4-(β-hydroxyethoxy)-phenyl] sulfone (HEPS) were stable up to 220 °C, exhibited 10% loss of mass at 313–424 °C, and had 39–62% residual mass at 700 °C in nitrogen. The polyphosphates derived from TMBS had glass transition temperatures between 128 and 173 °C which were about 60 °C higher than that of the polyphosphate obtained from BPS. The X-ray diffraction patterns revealed that almost all the polyphosphates were semicrystalline and the polymers containing the flexible ether linkage (polymer Ie, IIe and IIIe) had a relatively large degree of crystallinity. The polyphosphates obtained from BPS had good flame retardancy and showed higher LOI values, as indicated by high limiting oxygen index values in the range of 30–65. The water contact angles of the polyphosphates derived from TMBS were larger than those of other polymers which have a higher oxygen content.