Flame retardant phosphorous-containing polymers obtained by chemically modifying poly(vinyl alcohol)

A new set of polymers, which could act as flame retardant additives by blending with “commodity” polymers, was synthesized by chemically modifying poly(vinyl alcohol) (PVA) through reaction with a phosphorous-containing reagent. The phosphorous-based moiety introduced was 1-oxo-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane, which has been reported to be a good flame retardancy promoter structure. For a larger application and better compatibility with thermoplastic polymers, we also introduced in the polymeric additives aliphatic (valeroyl group) or aromatic (benzoyl group) moieties. The structures and properties of the polymers obtained were studied by 1H, 13C and 31P NMR, infrared spectroscopy (FTIR-ATR), inherent viscosity, inductively coupled plasma-atomic emission spectrometry (ICP-AES), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A detailed study of their thermal degradation was performed by thermogravimetry coupled with mass spectrometry (TG-MS) and pyrolysis. Their thermal behavior and high char yield at high temperatures make them promising candidates to act as flame retardant additives through the formation of protective barriers.