Journal of Applied Polymer Science, Vol.65, No.1, 59-65, 1997
Preparation and Properties of Flame-Retardant Polyphosphate Esters - Low-Temperature Solution Polycondensation of 3,3’,5,5’-Tetrabromobisphenol Af and Aryl Phosphorodichloridates
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, C-13 and P-31 nuclear magnetic resonance spectra, elemental analysis, inherent viscosity, thermogravimetric analysis, differential scanning calorimetry, 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 degrees C and had 14-26% residual mass at 700 degrees 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 degrees 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 (theta(w)) of all of the polyphosphates were in the range of 74-87 degrees. 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).