Study of thermal properties of intumescent additivePentaerythritol phosphate alcohol

Bicyclic compounds containing phosphorus on their skeleton such as 2,4,6-trioxa-1-phosphabicyclo[2,2,2]octane-4-methanol phosphate (PEPA) having three active ingredients required for intumescence have been synthesized. The structural characterization of PEPA was carried out by FT-IR, 1H and 13C NMR. The thermal behaviour of the material was studied using TGA, TGA--MS and pyrolysis GC--MS. Thermogravimetric analysis reveals that PEPA undergoes several stages of degradation with a char of about 12% at 800 ?C. The TGA--MS studies indicate that the material degrades with the liberation of water, formaldehyde, alkene and alcohols as the major degradation products. Pyrolysis GC--MS results reveal that PEPA isomerizes in the acidic medium. PEPA and/or isomers of PEPA react with formaldehyde, one of the degradation products, to form cross-linked structure and cyclic products with the elimination of water molecule. The thermal degradation mechanisms for PEPA are presented and discussed.