Cotton/alginate blended knitted fabrics: flame retardancy, flame-retardant mechanism, water absorption and mechanical properties

The influence of the weaving method on the flame retardancy of the fabrics prepared cannot be ignored. In this work, the thermal stability, flame retardancy, flame-retardant mechanism, mechanical properties and water absorption of cotton/alginate blended knitted fabrics were investigated. Thermogravimetric analysis results showed that the char residues at 700 degrees C of cotton/alginate blended knitted fabrics increased both in N-2 and air. In the cone calorimetry test, compared with cotton knitted fabrics, the fire growth rate index of cotton5/alginate5 decreased from 2.63 to 1.40 kW m(-2) s. Thermogravimetric analysis coupled with Fourier transform infrared analysis indicated that the cotton/alginate blended knitted fabrics released more non-flammable gases and fewer inflammable products containing carbonyl and ether groups. Analysis of Raman spectra showed that the char residues of cotton5/alginate5 had a higher degree of graphitization. The analysis of X-ray photoelectron spectroscopy spectra proved the existence of CaCO3 and CaO in the char residues. Moreover, the introduction of alginate fibers improved the water absorption and water retention properties of cotton knitted fabrics, but reduced its mechanical properties.