Sulfonamide-Derived Polymer Grafting onto Polypropylene Nonwoven Fabrics for Antibacterial Applications

Abstract Polypropylene (PP) nonwoven fabrics are widely used in medical and hygiene applications because of their light weight, mechanical strength, chemical stability, and low cost. Since the global pandemic, the demand for antibacterial materials has increased, emphasizing the need for PP nonwoven fabrics with durable antibacterial properties. However, conventional antibacterial approaches based on the physical incorporation of inorganic nanoparticles often suffer from particle detachment and leaching, leading to a decline in long-term antibacterial performance. To address these limitations, this study proposes a chemical immobilization strategy based on covalent grafting rather than physical mixing. Sulfonamide-based antibacterial monomers were designed according to structure–activity relationship (SAR) principles and chemically grafted onto PP nonwoven fabrics via a Norrish type II photoinitiated grafting reaction under mild UV irradiation. Sulfonamide antibiotics were selected due to their well-established SAR, structural stability, and compatibility with radical polymerization. An acryloyl-functionalized sulfonamide monomer (ASDM) was synthesized and successfully polymerized, as confirmed by 1 H NMR analysis, achieving a monomer conversion of 93%. Antibacterial activity evaluated using ASTM E2149 demonstrated that both the sulfonamide monomer and its polymer achieved a 99.9% reduction of Escherichia coli, indicating that antibacterial activity was retained after polymerization. The antibacterial polymer was subsequently grafted onto PP nonwoven fabrics through a grafting-from approach, forming covalent bonds with the PP surface, as confirmed by FT-IR analysis, water contact angle measurement, and mass increase. The resulting PP nonwoven fabrics exhibited effective antibacterial performance in JIS L 1902 tests, demonstrating a durable and promising strategy for long-term medical and hygiene applications.