Optimization of monoguanidine dihydrogen phosphate and amino propylethoxysilane based flame retardant formulations for cotton

Different formulations based on monoguanidine dihydrogen phosphate (MGHP) and 3-amino propylethoxysilane (APS) were evaluated as flame retardant in padding for cotton. The formulations can be classified into two groups. The first corresponds to the formulations of MGHP and APS, at pH 4 (obtained by the addition of phosphoric acid) and the second group to formulations at pH 9.5. Their thermal stability is then examined using thermal analysis. TG analysis reveals a significant difference in the thermal degradation of these two groups. While the degradation is initiated at lower temperatures for all padded fabrics compared to untreated cotton, the residual amounts of char are higher at 800 °C for formulations with phosphoric acid. Flame behaviour of the treated cotton fabrics was evaluated using the electrical burner test and was studied with cone calorimeter as fire model. The RHR peak was decreased very much for all the formulations, compared to the RHR peak of the virgin cotton. The highest decrease was achieved with the formulations at pH 4. The padded fabrics evolve smallest quantity of CO₂.