Synthesis, characterization, and fire retardancy of ferrocene containing polyphosphate esters

Abstract
Polyphosphate esters containing ferrocene structures were synthesized from 1,1′‐bis (p‐hydroxyphenylamido) ferrocene and 1,1′‐bis (p‐hydroxyphenoxycarbonyl) ferrocene with aryl phosphorodichloridates by interfacial polycondensation using a phase transfer catalyst. The polymers were characterized by infrared, 1H‐, 13C‐, and 31‐NMR spectroscopy. The molecular weights were determined by end group analysis using 31P‐NMR spectral data. The thermal stability and fire retardancy were respectively determined by thermogravimetry and limiting oxygen index (LOI) measurements. The polyamide‐phosphate esters showed better thermal stability and higher LOI values than the polyester‐phosphate esters.