Comparative performance of flame retardancy, physiological comfort, and durability of cotton textiles treated with alkaline and acidic casein suspension

The objective of the present study was to investigate the effect of coating of different concentrations and pH of aqueous casein suspension on thermo-oxidative properties, flame retardant behavior as well as physiological comfort of cotton fabrics. The flame retardant behavior was found to increase with increase in concentration of casein suspension in both alkaline and acidic pH conditions. The burning rate of 2.1 mm/s and 2.4 mm/s was measured for the samples of 150 g/L casein suspensions in acidic and alkaline pH, respectively. Moreover, better thermo-oxidative properties were obtained for the samples of casein suspension prepared in acidic pH than alkaline pH. The 150 g/L casein produced 19% and 28% residue, respectively for alkaline and acidic suspensions at 600℃. Furthermore, the phenomenon of intumescence was largely observed in case of samples coated with acidic casein suspension due to easier release of ammonia from protonated casein. These samples further exhibited relatively better durability against water washing and UV ageing as compared to those treated with alkaline casein suspension, however delivered poor physiological comfort properties due to blockage of fabric porosity by higher viscosity of casein in acidic pH.