Preparation and properties of flame-retardant polyphosphate esters: Low-temperature solution polycondensation of 3,3,?5,5?-tetrabromobisphenol AF and aryl phosphorodichloridates

Abstract

This article describes the syntheses of aromatic polyphosphates from the reaction of various aryl phosphorodichloridates with 3,3',5,5'-tetrabromobisphenol AF (TBPAF) in a chlorinated hydrocarbon solvent under low-temperature conditions. The new polyphosphates obtained were characterized by infrared, 13 C and 31 P NMR spectra, elemental analysis, inherent viscosity, TGA, DSC, X-ray diffraction, limiting oxygen index, contact angle, and molar mass measurement. All of the polyphosphates obtained had high yields, and the inherent viscosities were in the range 0.12-0.15 dL g -1 . All of the polymers start degrading between 210 and 267°C and had 14-26% residual mass at 700°C in nitrogen. Polymer E, having a methoxy group in the side chain phenyl ring, showed better thermal stability than the other polymers. The X-ray diffraction patterns revealed that all of the polyphosphates were amorphous. These polyphosphates had glass transition temperatures between 140 and 154°C. Polymers obtained from TBPAF had excellent flame retardency, as indicated by high limiting oxygen index values in the range of 63-68. The water contact angles (θ w ) of all of the polyphosphates were in the range of 74-87°. The contact angles of polymers A and B were larger than those of other polyphosphates that contain more oxygen (polymers C and E) or bromine atoms (polymer D).