Synthesis, characterisation, investigation of flame retardancy properties and thermal stability of two new phosphoramides with cotton fabric

Phosphorus and nitrogen-containing compounds widely are used as flame retardant for cotton fabrics. In this paper, two new phosphoramides with the formula of (C6H5)2P(O)[N-C3H5N2O] (DIO) and (C6H5)2P(O) [N-C3H5N2S] (DIT) were synthesised and characterised using 1H NMR, 13C NMR, 31P NMR, IR, and MASS spectroscopy. Crystal structures of DIO were investigated using X-ray crystallography to confirm the proposed structure. Experimental analyses such as VFT, LOI, SEM-EDS, TGA-DTG and cone caloriometer, indicated these compounds are noteworthy because of their thermal and flame retardancy properties. According to the cone calorimetric results, DIT/ cotton owning THR (18.26) and HRR (183.37) is better flame retardant than DIO/ cotton. After treatment with DIO and DIT, the mechanical properties of cotton decreased and improved slightly, respectively. In order to understand the Structure-Flame retardancy Relationship (SFR) of synthesized compounds, the values of HOMO and LUMO energies, dipole moments, hardness, softness, and electrophilicity index were investigated computationally by density functional theory (DFT) method. These results were in good accordance with those of flame retardancy investigation.

Automated summary

This paper investigates the performance of two new phosphorus and nitrogen-containing compounds as flame retardants for cotton fabrics. Through experimental analysis and computational simulation, it was found that these compounds possess good thermal and flame retardancy properties.