Preparation of silicone containing 2,2,6,6-tetramethyl-4-piperidinol-based N-chloramine for antibacterial polyethylene via interpenetration in supercritical carbon dioxide

Functionalization of polyethylene (PE) with powerful biocides through a friendly and efficient procedure is necessary to obtain extended applications. A novel CO2-philic 2,2,6,6-tetramethyl-4-piperidinol (TMP)-based N-chloramine silicone was synthesized via Pt-catalyzed silane alcoholysis between the Si-H of poly(methylhydrosiloxane) and O-H of TMP and followed by chlorination of amine N-H originating from TMP to N-Cl. The TMP-based N-chloramine silicone was interpenetrated into PE using supercritical carbon dioxide (scCO(2)) as working solvent. It was shown that the thickness of the TMP-based N-chloramine silicone layer on PE can be easily controlled by the interpenetration pressure, reaching a maximum value of 70 nm at 28 mp. The synthetic procedures and the interpenetration results were characterized by Fourier transform infrared, scanning electron microscopy, and X-ray photoelectron spectroscopy. In contrast with pristine PE that did not show biocidal ability, the TMP-based N-chloramine silicone modified PE imparted powerful antibacterial abilities, exerting total kills of both Staphylococcus aureus and Escherichia coli of similar to 10(7) cfu mL(-1) in 30 min. The biocidal functionality was durable toward washings, storage, and ultraviolet exposure and the recoverability of lost chlorines was good. The interpenetration in scCO(2) tactic provides an environmentally friendly and universal approach to functionalize inert substrates due to no needs of harmful solvent and chemical linkages with biocides. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47614.