Modification of medical grade PVC with N-vinylimidazole to obtain bactericidal surface

• Grafting of poly(N-vinylimidazole) onto medical grade poly(vinylchloride) catheters.
• Determination of reaction conditions to carry out the grafting with gamma rays.
• Modified PVC catheters show antimicrobial activity.
• PVC-g-VIm catheters may be suitable for the development of new medical devices.

N-vinylimidazole (VIm) was grafted onto medical-grade poly(vinyl chloride) (PVC) catheters in order to provide a bactericidal surface that make them less susceptible to microbial colonization. The grafting of VIm was carried out by means of gamma rays using the direct method, which demonstrated to be an efficient and fast procedure for obtaining PVC-g-VIm copolymers. These copolymers could be quaternized in a second step using methyl iodide (CH3I). The effects of solvent nature, absorbed dose, and monomer concentration on the grafting yield were investigated. Modified PVC catheters were characterized by means of Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TGA), and swelling studies. PVC-g-VIm copolymers both before and after quaternization showed good hemocompatibility, while quaternization was required to inhibit the growth of Staphylococcus aureus.