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Radiation-grafting of N-vinylcaprolactam and 2-hydroxyethyl methacrylate onto polypropylene films to obtain a thermo-responsive drug delivery system

Abstract:

2-Hydroxyethyl methacrylate (HEMA) and N-vinylcaprolactam (NVCL) were grafted onto polypropylene films (PP) by radiation-induced grafting, using gamma-radiation (from a 60Co gamma source) with the aim of improving their surface properties and endow the films with the ability to act as drug-eluting materials. Different γ-radiation doses, reaction temperatures, and monomer concentrations were tested to understand the effect that each variable had on the grafting yield of each compound in separate, and to identify the optimum grafting conditions. The PP films were grafted using the pre-irradiation oxidative method, in a one- and two-step procedure, to obtain binary grafts of various architectures, namely (PP-g-HEMA)-g-NVCL, (PP-g-NVCL)-g-HEMA, and PP-g-(HEMA-co-NVCL). The untreated and modified PP films were characterized by infrared spectroscopy (FTIR-ATR), thermal analyses (DSC and TGA), swelling degree, and contact angle measurements. The temperature responsiveness of the films was evaluated through changes induced at the lower critical solution temperature (LCST), which allowed the material to load and release benzalkonium chloride and ciprofloxacin.