Radiation-induced grafting of vinylbenzyltrimethylammonium chloride (VBT) onto cotton fabric and study of its anti-bacterial activities

Mutual radiation grafting technique using 60Co gamma radiation has been used to carry out grafting of vinylbenzyltrimethylammonium chloride (VBT) onto cotton cellulose substrate. Grafting yield increased with radiation dose and decreased with dose rate but was adversely affected by the presence of O2 and salts of Fe2+ and Cu2+. However, the presence of an acid did not affect grafting in the concentration range studied. The effect of organic solvents like methanol, ethanol, n-propanol, iso-propanol, tert-butanol on grafting yield was investigated in the mixed aqueous solvent system. The VBT grafted cotton samples showed significantly higher water uptake and water retention properties and possessed excellent anti-bacterial activity against strains like Escherichia coli and Staphylococcus aureus. Samples with 25% grafting extent showed 6 log cycles reduction in bacterial counts within 6 h of exposure time. The anti-bacterial activity of the grafted cotton samples was retained after several cycles of washing and drying in a commercial detergent powder.