Halogen free phosphorus-based hybrid silica coatings for conferring flame retardancy to cellulosic fabrics

The present study involves the use of hybrid sol-gel coatings based on silica and phosphorous compounds to develop flame retarded cotton fabrics. To this aim, diethylphosphatoethyltriethoxysilane (DPTS) precursor has been used for the synthesis of several sols in combination with different chemical additives. The DPTS sols were reacted with azo-based compounds to investigate the effect of the concurrent presence of Si, P and N and applied in consecutive depositions on textile samples. Flammability tests were performed to evaluate the flame retardancy of treated cellulosic fabrics. The obtained results have shown that phosphorus-silica network is able to promote the formation of char that acts as insulator barrier. An additive P-N effect of the ceramic oxide matrix in terms of increased residue and decreased heat release rate and total burning time has been observed.