Synthesis of flame retarding polyphosphates and polyphosphonates

Abstract

Aromatic polyphosphonates and polyphosphates were synthesized from phnylphosphonic dichloride, p-bromophenylphosphorodichloridate and p-methylphenylphosphorodichloridate with bisphenol A, bisphenol E, bisphenol P-1,3, bisphenol P-1,4 and bisphenol C by low-temperature solution polycondensation. The polymers were characterized by IR, ¹H, ¹³C and ³¹P-NMR spectroscopy. The weight average molecular weight were determined by gel permeation chromatography. The thermal stability of polymer was studied by differential scanning calorimetry and thermogravimetric analysis. Preliminary indicating factor on polymer flammability was investigated by measuring the limiting oxygen index (LOI). Factors affecting weight average molecular weight as well as the relationship between the structure, thermal properties and flammability of polymer were studied. Polyphosphates and polyphosphates with high phosphorus percentage, as well as, polyphosphates containing bromine atoms gave high LOI values.