Multi-functional wool fabrics by graft-copolymerisation with polystyrene sulphonate: their enhanced fire retardancy, mechanical properties, and stain-resistance

Multi-functionalisation of textile fibres is quite important to extend their range of applications. In this respect, a single treatment that offers multi-functional properties to textile fibres is highly desirable because it minimises the processing cost by reducing the number of chemicals required and the processing time. In this work, wool fibres were graft copolymerised with poly(styrene sulphonate) or pSS to enhance their fire-retardancy, antibacterial activity, antistatic properties, stain-resistance, and tensile strength. The pSS-grafted-wool fabrics were characterised by Fourier transform infrared spectroscopy, elemental analysis, differential scanning calorimetry, and tensile strength measurements. The fire retardancy and the thermal stability were assessed by measuring the limiting oxygen index (LOI) and by thermogravimetric analysis, respectively. The pSS-grafted wool fabrics showed enhanced fire retardancy, as the LOI value increased from 24.5 for the untreated control fabric to 28.0 for the fabric grafted with 25% pSS. The pSS-grafted fabrics also showed an improved tensile strength and stain-resistance against C.I. Acid Red 40. The pSS-grafted fabric that was further treated with 0.5% AgNO3 not only showed excellent antibacterial activity against Staphylococcus aureus and Klebsiella pneumonia measured according to the AATCC Test method 147-1999 but the antibacterial activity was durable for at least 20 washes and also showed enhanced antistatic properties. Thus, the developed treatment could be used in the textile industry to make wool fabrics multi-functional.