Durable Antibacterial Cotton Fabrics Containing Stable Acyclic N-Halamine Groups

Inexpensive and commercially available methylene-bis-acrylamide (MBA) was covalently bonded onto the cotton fabrics by an effective catalytic solid-state reaction in water. The as-prepared MBA grafted cotton fabric (cotton MBA) was characterized by field emission scanning electron microscopy image and Fourier transform infrared spectroscopy spectra. After a facile chlorination in diluted NaOCl solution, the amide functional groups in cotton-MBA were converted to N-halamine ones and durable antibacterial cotton fabric containing stable noncyclic N-halamine groups (cotton MBA Cl) was achieved. Antimicrobial testing showed that the cotton MBA Cl could effectively inactivate 5.78 X 10(7) CFU/mL of S. aureus and 7.58 X 10(8) CFU/mL of E. coli 0157:H7 completely within 1 min of contact time. Washing durability testing indicated that the oxidative chlorine percentage of the cotton-MBA-Cl decreased from 0.43% to 0.06% after 50 washing cycles and was recovered to 0.30% via a simple rechlorination. It means that the N-halamine antimicrobial groups and the covalent bonds between MBA and cotton are very resistant to washing. Storage stability testing showed that the oxidative chlorine percentage of the cotton MBA Cl decreased from 0.43% to 0.32% after 30 day's storage under room temperature, indicating that N-halamine functional groups are stable. Furthermore, it was found that the grafting and chlorination processes did not have any obvious bad effect on the tensile strength of cotton fabrics due to the mild grafting and chlorination conditions.