Synthesis and characterization of a phosphorous/nitrogen based sol-gel coating as a novel halogen- and formaldehyde-free flame retardant finishing for cotton fabric

[object Object]A novel formaldehyde- and halogen-free coating, containing phosphorus, nitrogen and silicon, wassynthesized with a promising approach to enhance flame retardancy of cotton fabric. To this aim, a newsol-gel precursor, comprising in the same molecule P, N and Si, namely (3-Glycidyloxypropyl triethoxysilane modified N-(phosphonomethyl) iminodiacetic acid (PGPTES), was co-hydrolysed and cocondensated with tetraethylorthosilicate (TEOS), as silane linker, and used for producing a selfextinguishing cotton fabric coating. The structure of PGPTES was characterized by 1H/13C/31P nuclearmagnetic resonance and the obtained coating was investigated by FT-Infrared Spectroscopy and ScanningElectron Microscopy. The thermal properties of the treated fabric were studied by ThermogravimetricAnalyses and Cone Calorimetry Tests. The obtained results show that the synthetized coating is able tocatalyse the dehydration and char formation of cellulose based polymer at a lower temperature, thanksto the thermal decomposition of phosphate giving rise to acidic intermediates, able to further react withcellulose-based fabric, hence improving the flame retardant properties of the latter.