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 × 107 CFU/mL of S. aureus and 7.58 × 108 CFU/mL of E. coli O157: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.

An effective macroporous cross-linked antimicrobial polymeric resin containing N-halamine and quaternary ammonium salt moieties was synthesized in an eco-friendly and economical way. Commercially available macroporous crosslinked chloromethylated polystyrene (CMPS) resin reacted with the salt of 5,5-dimethylhydantoin (DMH) and trimethylamine (TMA) in water to produce a polymeric resin containing hydantoinyl and quaternary ammonium salt moieties, poly(p-methylstyrene)-3-(5,5-dimethylhydantoin)-co-trimethyl ammonium chloride (PSHTMA). The hydantoinyl groups in PSHTMA were converted to an antimicrobial N-halamine structure by a facile chlorination reaction in dilute NaOCl solution. The as-synthesized antimicrobial polymeric resin (Cl-PSHTMA) was characterized by FT-IR, X-ray photoelectron spectroscopy, and zeta-potential measurement. The antimicrobial tests showed that the as-synthesized antimicrobial polymeric resin was capable of 7-log inactivation of S. aureus and 8-log inactivation of E. coli within 1 minute contact time. Moreover, the N-halamine moieties in Cl-PSHTMA exhibited excellent regenerability.

A novel regenerable antimicrobial silica gel was prepared by a dehydration between silanols of silica gel and hydrolyzed 3-chloropropyltrimethoxysilane, a quaternization between grafted hydrolyzed 3-chloropropyltrimethoxysilane and (5,5-dimethylhydantoinyl-3-ylethyl)-dimethylamine (DHEDA), and a chlorination of amide groups of DHEDA. The as-prepared antimicrobial silica gel was characterized by FT-IR and X-ray photoelectron spectroscopy. Antimicrobial tests showed that the as-prepared antimicrobial silica gel was capable of about a 6-log inactivation of Staphylococcus aureus and Escherichia coli O157:H7 within 10 min of contact. Interestingly, more than 2 × 104 CFU/mL of Escherichia coli O157:H7 could be almost inactivated under flowing water condition. Furthermore, the as-prepared antimicrobial silica gel exhibits good regenerability and storage stability.