Preparation of biocidal 4‐ethyl‐4‐(hydroxymethyl)oxazolidin‐2‐one‐basedN‐halamine polysiloxane for impregnation of polypropylene in supercritical CO₂

Abstract

A cyclic N‐halamine precursor, 4‐ethyl‐4‐(hydroxymethyl)oxazolidin‐2‐one (EHMO), was synthesized and attached to poly(methylhydrosiloxane) (PMHS) through silane alcoholysis between the OH of EHMO and SiH of PMHS. The alcoholysis product was chlorinated with tert‐butyl hypochlorite to transfer the NH to NCl and obtain an EHMO‐based N‐halamine polysiloxane. The N‐halamine polysiloxane was impregnated into inert polypropylene (PP) fibers and formed a 72 nm coating layer using supercritical carbon dioxide (scCO2) as solvent and swelling reagent at 28 MPa and 50 °C for biocidal application. The overall synthetic procedure and the impregnation process were characterized by FTIR, XPS, and SEM, respectively. The N‐halamine polysiloxane layer on PP imparted potent antibacterial abilities against both Staphylococcus aureus and Escherichia coli while pristine ones did not exhibit noticeable killing activities. Stability tests showed that the N‐halamine polysiloxane layer was resistant to washing cycles, storage, and UV irradiation and the rechlorination of lost chlorines was good. The strategy of using CO2‐philic PMHS as carrier polymer and scCO2 as working solvent for impregnation presents a general and friendly procedure to functionalize inert substrates without the need of chemical linkage and organic solvent. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46624.

Synthesis of Multi‐Functionalized N–Cl Hydantoin Polyurethane for Chemical Warfare Agent Decomposition with High N–Cl Stability

“…However, after several trials, we have concluded that the N‐Cl is very unstable, especially in high active N‐Cl amount (above 1.0 wt%). It is noteworthy that most of the previous researches reporting N‐Cl stability have utilized N‐Cl object with low level of N‐Cl concentration . In addition, the surface area of those antibiotic films will be much lower than our catalytic NIPS membrane or electrospun web.…”

“…It is noteworthy that most of the previous researches reporting N-Cl stability have utilized N-Cl object with low level of N-Cl concentration. [15] In addition, the surface area of those antibiotic films will be much lower than our catalytic NIPS membrane or electrospun web. Although there are few numbers of papers describing high stability of N-Cl at high concentration, we cannot obtain enough stability at high concentration with large surface area.…”

“…[37,38] Several researches have also paid their attention on the stability of N-Cl as described in Supporting Information 1. [14][15][16][29][30][31][32][33][34][39][40][41][42][43][44][45] Based on the previous literature, the N-Cl groups seem to be quite stable and have long enough shelter time before usage. However, it has been worthwhile to check that the active N-Cl concentration was around 0.5-1 wt% in most of them, which might be good enough in biocidal applications.…”

“…Broad range of researches has been reported considering their synthetic procedures and applications. [12][13][14][15][16][17] great potential in developing stable N-Cl functionalized polymer platform, which can be used in antimicrobial and detoxification agents against harmful chemical. 3,3,4,4,5,5,6,6,7,7,8,8,8-…”

Long‐term‐durable anti‐icing superhydrophobic composite coatings

“…Common issues for fabricating MWCNT–CNF composites are nanostructural flaws, agglomeration, and poor adsorption between the two materials; this almost leads during the MWCNT–CNF processing . The most used techniques for fabricating such carbon composites are solution processing, in situ polymerization, the supercritical carbon dioxide method, and melt blending, all of which happen in the fluid phase . Conversion from the fluid to the solid phase takes quite a while and commonly happens in various unstable manners; this almost promotes agglomeration .…”