With the ever-growing public health awareness of disease transmission, crossinfections and malodors, barrier materials are having increasing applications as protective clothing materials for medical and chemical workers, sportswear and underwear. In our previous study, microporous polyurethane (PU) membranes were modified by grafting hydrophilic polymer onto the surfaces and within the pores of the membranes to enhance moisture transport while reducing the pore size to improve the barrier properties. For enhanced performance, antimicrobial properties are desirable for use in health related applications.

Commonly used antimicrobial agents, such as antibiotics, silver ions, quaternary ammonium, the relatively new N-halamines and other biocidal agents, can be applied onto textiles and membrane materials by various chemical and physicochemical finishing techniques to protect the substrates from biological activities. In this study, the effect of N-halamine chemistry on microporous PU membrane was explored by grafting a hydantoin moiety onto PU membrane surface as an N-halamine precursor. A combination of techniques was used to characterize this surface modification. Thermal and mechanical properties of the surface modified PU membranes were evaluated accordingly. Upon exposure to certain concentration of chlorine bleach, the hydantoin structures on the grafted PU membranes were transformed into N-halamines, which provided potent antimicrobial activities against both gram-negative and gram-positive bacteria. A total reduction was observed for the TMIO modified PU membrane after a two hour contact period. Consequently, a microporous membrane that not only possesses good barrier and hygiene protections, but also maintains sufficient comfort properties in terms of water vapor transmission rate (WVTR) was developed.