Dual action bactericides: Quaternary ammonium/N‐halamine‐functionalized cellulose fiber

Bi‐functional antibacterial material was prepared by co‐grafting N‐halamine and quaternary ammonium salt monomers from cellulose fiber. The grafted fiber was characterized by Fourier transform infrared spectra, and X‐ray photoelectron spectra. The N‐halamine derived from the precursor 4‐[(acryloxy)methyl]‐4‐ethyl‐2‐oxazolidinone via chlorination treatment and the oxidative chlorine (Cl⁺) leaching behavior were investigated. The antibacterial activities of singly (only QAs‐functionalized or only Cl⁺‐releasing) and dual (QAs‐functionalized and Cl⁺‐releasing) functional cellulose fibers were tested against Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus. Compared to singly functionalized formulations, the bi‐functional cellulose fiber exhibited excellent and rapid bactericidal performance against both E. coli and S. aureus. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40070.     

Preparation of antibacterial cellulose with s‐triazine‐based quaternarized N‐halamine

To reduce the neutral salt used in the textile finishing with s‐triazine derivatives, a novel s‐triazine‐based quaternarized N‐halamine precursor was synthesized by two simple steps and characterized by H‐NMR and FT‐IR. This compound can be effectively coated onto cellulose by nucleophilic substitution process without neutral salt. The treated cellulose was rendered with powerful biocidal efficacy after transferring to an N‐halamine structure by exposing to dilute sodium hypochlorite solution through the synergistic antimicrobial effect quaternary ammonium salt and N‐halamine. The chlorinated samples could inactivate 6‐logs of Staphylococcus aureus and Escherichia coli O157:H7 within 1 min and 5 min, respectively. In addition, about 50% of oxidant chlorine remained after 50 washing cycles and 30 days storage, and all of the lost active chlorines in the N‐halamine molecules recovered after exposing to bleach solution. With these advantages, the as‐prepared antimicrobial fabrics will have potential application, especially in the medical and healthcare textiles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44998.     

Durable and regenerable antimicrobial textiles: Synthesis and applications of 3‐methylol‐2,2,5,5‐tetramethyl‐imidazolidin‐4‐one (MTMIO)

A new precursor of halamine compounds, 3‐methylol‐2,2,5,5‐tetramethylimidazolidin‐4‐one (MTMIO), was synthesized by methylolation of 2,2,5,5‐tetramethylimidazolidin‐4‐one (TMIO) and characterized by ¹H‐NMR and FTIR. By chemically reacting MTMIO with cellulose, TMIO rings were successfully grafted onto cellulose‐containing fabrics. After a subsequent chlorination, the treated fabrics were converted to halamine structures, which then demonstrated effective antibacterial efficacy. As expected, the halamine structure generated from TMIO is much more stable, and therefore, the biocidal functions of the finished materials are more durable. The results indicated that this halamine structure could survive repeated home laundering and would require less frequent chlorine recharging to maintain the biocidal properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2418–2425, 2003     

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

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.     

Novel regenerable N‐halamine polymeric biocides. II. Grafting hydantoin‐containing monomers onto cotton cellulose

A novel cyclic‐amine monomer, 3‐allyl‐5,5‐dimethylhydantoin (ADMH) was synthesized with good yield by the reaction of allyl bromide with 5,5‐dimethylhydantoin (DMH), and was characterized by FTIR and ¹H‐NMR spectra. ADMH alone cannot be grafted onto other polymers. However, the presence of acrylonitrile markedly enhanced the ADMH graft yield onto cotton cellulose. The influence of reaction conditions on the graft copolymerization was investigated. After chlorine bleach treatment, hydantoin units in the grafted copolymers were easily transformed into N‐halamine structures. Grafted samples exhibited potent antibacterial activity against Escherichia coli, and the functional properties were shown to be durable and regenerable. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 617–624, 2001     

Synthesis of polysiloxane with 5,5‐dimethylhydantoin‐based N‐halamine pendants for biocidal functionalization of polyethylene by supercritical impregnation

An N‐halamine precursor 3‐(3‐hydroxypropyl)‐5,5‐dimethylhydantoin (HPDMH) has been synthesized. The N‐halamine precursor was reacted with poly(methylhydrosiloxane) (PMHS) to produce a biocidal polysiloxane with 5,5‐dimethylhydantoin‐based N‐halamine pendants through silane alcoholysis and subsequent chlorination of hydantoin ring with tert‐butyl hypochlorite. The N‐halamine polysiloxane was impregnated into inert polyethylene (PE) fibers and formed a 68‐nm coating layer in supercritical carbon dioxide (scCO₂) for antibacterial application. The PE fibers before and after impregnation were characterized by XPS and SEM. The N‐halamine polysiloxane impregnated PE samples provided effective biocidal activities against both Staphylococcus aureus and Escherichia coli compared with unmodified ones that did not display obvious antibacterial activities. The coating layer on PE substrate was stable toward washing cycles, storage, and UV irradiation and the rechargeability of lost active chlorines was good. The scCO₂ impregnation approach uses environmentally friendly CO₂ as solvent and can be applied to both reactive and nonreactive substrates since it does not require covalent bonds to tether biocidal moieties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44721.     

Synthesis of chitosan derivative with dual‐antibacterial functional groups and its antibacterial activity

The O‐fumaryl ester (OFTMCS) of N,N,N‐trimethyl chitosan (TMCS) has been synthesized as a water‐soluble chitosan (CS) derivative bearing dual‐functional groups, with the aim of discovering novel CS derivatives with good water solubility and enhanced the antibacterial activity compared with unmodified CS. OFTMCS was characterized by FT‐IR, ¹³C NMR, XPS, XRD and Zeta potential analyses. The XPS results indicated that the degree of substitution (DS) on the C₂‐NH₂ group of the CS was 0.78, and that the DS on its C₆‐OH group was 0.31. The TGA results showed that the thermal stability of OFTMCS was lower than that of unmodified CS. The antibacterial activities of OFTMCS were investigated by assessing the mortality rates of the representative Gram‐positive and Gram‐negative bacteria Staphylococcus aureus and Escherichia coli, respectively. The results indicated that OFTMCS exhibited superior antibacterial activity to CS at a lower dosage. The synthesis of CS derivatives bearing dual‐functional groups could therefore be used as a promising strategy to enhance the antibacterial activity of CS. The antimicrobial mechanism of action of OFTMCS was discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42663.     

One pot blending of biopolymer‐TiO2 composite membranes with enhanced mechanical strength

A biopolymer‐TiO₂ composite membrane was prepared by blending of N‐[(2‐hydroxy‐3‐trimethylammonium) propyl] chloride chitosan and cellulose acetate with nano‐TiO₂ particles as the introduced inorganic components. It was verified that the amino groups (? NH₂) of chitosan (CTS) were partly grafted by stronger hydrophilic group ? according to the ¹H‐nuclear magnetic resonance spectra of N‐[(2‐hydroxy‐3‐trimethylammonium) propyl] chloride chitosan and attenuated total reflectance Fourier transform infrared spectroscopy. The structure, microcosmic morphology, water flux, swelling properties, and thermal stability of the composite membranes were characterized. With the mass ratio of cellulose acetate to CTS being 50 wt %, the mole ratio of CTS to glycidyl trimethylammonium chloride being 1 : 1, and drying temperature being 60°C in 70% acetic acid, the formed biopolymer‐TiO₂ composite membranes exhibited enhanced mechanical strength (84.29 MPa), lower swelling degree (101.36%), and improved antibacterial activity against Gram‐negative Escherichia coli (Rosetta and DH5α) and Gram‐positive Bacillus subtilis. The existence of nano‐TiO₂ particles and the introduction of stronger cationic group synergistically improved the antibacterial properties of the biopolymer‐TiO₂ composite membranes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42732.     

N‐halamine‐modified polyglycolide (PGA) multifilament as a potential bactericidal surgical suture: In vitro study

In this study, new cationic homopolymer and anionic copolymer were synthesized, and deposited onto polyglycolide sutures using a layer‐by‐layer assembly technique. The coated sutures were rendered antibacterial by chlorinating with dilute solution of household bleach solution at pH 7. The chlorination treatment transformed the N? H groups of anionic copolymer into N‐halamine structures. The N‐halamine‐modified sutures were challenged with Staphylococcus aureus and Escherichia coli O157:H7 bacteria at different contact times. The suture with chlorine loading of 0.22% completely inactivated both bacterial strains in 30 min contact time. Fourier transform infrared spectroscopy, scanning electron microscopy, and analytical titration confirmed the successful deposition of the N‐halamine multilayers. The effect of layer‐by‐layer coatings of polyelectrolytes on the chlorine loading and antibacterial efficacy of sutures was evaluated. The straight‐pull and knot‐pull strength tests performed on the sutures reported slight decline in tensile properties after chlorination treatment. The in vitro hemolysis and cytocompatibility tests revealed that the N‐halamines‐based antibacterial sutures were biocompatible. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42483.     

Novel regenerable N‐halamine polymeric biocides. I. Synthesis,characterization, and antibacterial activity of hydantoin‐containing polymers

Two novel cyclic‐amine monomers, i.e., 3‐allyl‐5,5‐dimethylhydantoin (ADMH) and 7,8‐benzo‐3 allyl‐1,3‐diazasprio[4.5]decane‐2,4‐dione (BADDD) were synthesized with good yields by reacting allyl bromide with 5,5‐dimethylhydantoin (DMH) and 7,8‐benzo‐1,3‐diazasprio[4.5]decane‐2,4‐dione (BDDD), respectively. The synthesized monomers were characterized by FTIR and ¹H‐NMR spectra, and copolymerized with acrylonitrile (AN), vinyl acetate (VAC), and methyl methacrylate (MMA) in a small monomer ratio of ADMH and BDDD, respectively. The copolymers were characterized by FTIR, ¹H‐NMR, and DSC studies. The N‐halamine derivatives of the corresponding copolymers were found to exhibit high antibacterial activities against Escherichia coli, and the antibacterial properties were durable and regenerable. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2460–2467, 2001     

Preparation of grafted cationic polymer/silver chloride modified cellulose fibers and their antibacterial properties

In this article, we present a simple method for synthesizing antibacterial cellulose fibers that were modified with a cationic polymer and immobilized silver chloride (AgCl) particles. Relatively simple techniques of graft polymerization and onsite precipitation were used to fabricate the composites. Scanning electron microscopy images, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, and energy‐dispersive X‐ray spectroscopy confirmed the immobilization of the AgCl particles. The observed inhibition zone of the immobilized AgCl particle composites indicated that the biocidal silver ions were released from the composites in aqueous solution. Compared with cationic‐polymer‐grafted cellulose fibers or AgCl alone, the cationic polymer/AgCl composites showed excellent antibacterial activity against Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42092.     

Antibacterial functionalization of cotton fabrics by electric‐beam irradiation

An N‐halamine precursor monomer, 2,2,6,6‐tetramethylpiperidinyl acrylate (TMPA), was synthesized and successfully grafted onto cotton fibers via an impregnation process (IP) and electron‐beam irradiation (EB). The grafted cotton fibers could provide antibacterial efficacy after chlorination through a dilute sodium hypochlorite solution. The antibacterial efficacy was challenged against Staphylococcus aureus and Escherichia coli. The cotton fibers grafted with TMPA and acrylic acid by EB inactivated all of the bacteria within 30 min of contact, whereas the samples grafted with TMPA via an IP could not completely kill the bacteria with 60 min. The breaking strength and UVA light stability also improved significantly. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42023.     

New antimicrobial polyurea: Synthesis,characterization, and antibacterial activities of polyurea‐containing thiosemicarbazide–metal complexes

A novel class of polymer–metal complexes was prepared by the condensation of a polymeric ligand with transition‐metal ions. The polymeric ligand was prepared by the addition polymerization of thiosemicarbazides with toluene 2,4‐diisocyanate in a 1 : 1 molar ratio. The polymeric ligand and its polymer–metal complexes were characterized by elemental analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy, and ¹³C‐NMR and ¹H‐NMR spectroscopy. The geometries of the central metal ions were determined by electronic spectra (UV–visible) and magnetic moment measurement. The antibacterial activities of all of the synthesized polymers were investigated against Bacillus subtilis and Staphylococcus aureus (Gram positive) and Escherichia coli and Salmonella typhi (Gram negative). These compounds showed excellent antibacterial activities against these bacteria with the spread plate method on agar plates, and the number of viable bacteria were counted after 24 h of incubation period at 37°C. The antibacterial activity results revealed that the Cu(II) chelated polyurea showed a higher antibacterial activity than the other metal‐chelated polyureas. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Antimicrobial polyethylene terephthalate (PET) treated with an aromatic N‐halamine precursor,m‐aramid

A commercial m‐aramid as N‐halamine precursor has been coated onto polyethylene terephthalate (PET) fabric surface by pad‐dry‐curing process. The process is accomplished by padding the scoured PET fabric through the homogeneous m‐aramid solution, drying at 150°C for 3 min, and curing at 230°C for 3 min. The PET surface coated with m‐aramid was characterized using fourier transform infrared‐attenuated total reflection (FTIR‐ATR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). FTIR exhibits new bands in the 1645 and 1524 cm^?1 regions as characteristic of m‐aramid bands, which indicate the PET fabric coated with m‐aramid. XPS results show a distinguishable peak at binding energy 398.7 eV, which confirms the nitrogen atom of m‐aramid on the PET surface. In addition, SEM image shows a layer of coating onto the PET surfaces, which demonstrates the presence of m‐aramid coating on the surface of the PET. After exposure to dilute sodium hypochlorite solution, exhibition of antimicrobial activity on the coated PET is attributed to the conversion of N‐halamine moieties from the N‐halamine precursor. The chlorinated PET showed high antimicrobial activity against Gram‐negative and Gram‐positive bacteria. The chlorinated PET coated with 10% m‐aramid exhibited about 6 log reductions of S. aureus and E. coli O157:H7 at a contact time of 10 and 30 min, respectively. Furthermore, the antimicrobial activity was durable and rechargeable after 25 wash cycles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

N‐(hydroxymethyl) acrylamide as a multifunctional finish to cotton and a tether for grafting methacrylamide for biocidal coatings

N‐(hydroxymethyl) acrylamide (NMA) was immobilized on cotton surfaces through etherification, and then methacrylamide (MA) was grafted onto the treated surface. The coatings were characterized by ATR‐IR spectroscopy and were rendered biocidal upon exposure to dilute household bleach. The treated fabrics were challenged with Gram‐negative and Gram‐positive bacteria; both NMA and NMA/MA‐treated fabrics inactivated about 8 logs of Escherichia coli O157:H7 and Staphylococcus aureus within only 5 min of contact time. The coatings were also quite stable toward ultraviolet (UVA) light exposure and repeated laundering. Moreover, a substantial improvement in wrinkle recovery angle was obtained for the NMA/MA‐treated fabrics. The new acyclic acrylamide N‐halamine coating should be less expensive to produce and use than previous cyclic N‐halamine coatings developed in these laboratories. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Development of antimicrobial stainless steel via surface modification with N‐halamines: Characterization of surface chemistry and N‐halamine chlorination

N‐halamine modification of materials enables the development of antimicrobial materials whose activity can be regenerated after exposure to halogenated sanitizers. Surface and bulk modification of polymers by N‐halamines has shown great success, however, modification of inorganic substrates (e.g., stainless steel) remains an area of research need. Herein, we report the covalent surface modification of stainless steel to possess rechargeably antimicrobial N‐halamine moieties. Multilayers of branched polyethyleneimine and poly(acrylic acid) were immobilized onto the surface of stainless steel and the number of N‐halamines available to complex chlorine was quantified. Samples were characterized through contact angle, Fourier transform infrared spectroscopy, ellipsometry, dye assay for amine quantification, and X‐ray photoelectron spectroscopy. Increasing the number of multilayers from one to six increased the number of N‐halamines available to complex chlorine from 0.30 ± 0.5 to 36.81 ± 5.0 nmol cm^?2. XPS and FTIR confirmed successful covalent layer‐by‐layer deposition of the N‐halamine multilayers. The reported layer‐by‐layer deposition technique resulted in a greater than seven‐fold increase of available N‐halamine compared to prior reports of N‐halamine surface modifications. The N‐halamine modified steel demonstrated antimicrobial activity (99.7% reduction) against the pathogen Listeria monocytogenes. Such surface modified stainless steel with increased N‐halamine functionality, and therefore potential for rechargeable antimicrobial activity, supports efforts to reduce cross‐contamination by pathogenic organisms in the food and biomedical industries. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Macroscopic N‐halamine biocidal polymeric beads

The particle size of N‐halamine biocidal polymers was methodically modified forming beads of different sizes by blending water‐insoluble N‐halamine polyurethane with sodium alginate as the matrix and loading heterocyclic rings onto modified silica gels. The biological activity of the prepared beads and halogenated modified silica derivatives was evaluated against examples of Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) bacteria. The recycling possibilities and the optimum preparation conditions of the blended beads were investigated; blending prehalogenated polyurethane (5%, w/v) with sodium alginate (3%, w/v) followed by crosslinking with CaCl₂ (10%, w/v) at 40°C are the optimum preparation conditions for the alginate beads. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Cytocompatible and regenerable antimicrobial cellulose modified by N‐halamine triazine ring

This study reports the formation of cyanuric chloride hydrolysate and its attachment onto cellulose fibers though covalent bonding. The hydrolysis product, 2,4‐dichloro‐6‐hydroxy‐1,3,5‐triazine, is prepared in water solution at ambient temperature, and directly used as a treatment solution for the treatment of cotton fabrics without any prior work‐up. The triazine treated fabrics are rendered antimicrobial through exposure to chlorine bleach. The oxidative chlorine bonded to the triazine‐treated cotton is very stable and regenerable to standard washing tests and UVA irradiation test. The N‐halamine modified cotton fabrics demonstrate excellent antimicrobial efficacy against Staphylococcus aureus ATCC 6538 and Escherichia coli O157:H7 ATCC 43895 with 7‐logs reductions within the contact time of 10 and 5 min, respectively. In addition, the results of in vitro cell viability test suggested that the N‐halamine modified fabrics have excellent cytocompatibility to mammalian cells. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40627.     

Manufacture and properties of chitosan/N,O‐carboxymethylated chitosan/viscose rayon antibacterial fibers

Chitosan/N,O‐carboxymethylated chitosan/viscose rayon antibacterial fibers (CNVFs) were prepared by blending chitosan emulsion, N,O‐carboxymethylated chitosan (N,O‐CMC), and viscose rayon together for spinning. The fibers were characterized by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). TEM micrographs showed that chitosan microparticles dispersed uniformly along the oriented direction with the mean size ranging from 0.1 to 0.5 μm. DSC spectra of these fibers showed that no significant change in thermal property was caused by adding chitosan and N,O‐CMC into the viscose rayon. TGA spectra showed that the good moisture retentivity was not affected by the addition of chitosan and N,O‐CMC. Both DSC and TGA suggested that the decomposing tendency of the viscose rayon above 250°C seemed to be weakened by the chitosan. The fibers' mechanical properties and antibacterial activities against Escherchia coli, Staphylococcus aureus, and Candida albicans were measured. Although the addition of chitosan slightly reduced the mechanical properties, the antibacterial fibers' properties were obtained and were found to meet commercial requirements. CNVF exhibited excellent antibacterial activity against E. coli, S. aureus, and C. albicans. The antibacterial activity increased along with the chitosan concentration and was not greatly affected by 15 washings in water. Scanning electron microscopy (SEM) was used to observe the morphology of bacteria cells incubated together with the antibacterial or reference fibers. SEM micrographs demonstrated that greater amounts of bacteria could be adsorbed by the antibacterial fiber than by the reference fiber; these bacteria were overwhelmingly destroyed and killed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2049–2059, 2002; DOI 10.1002/app.10501     

Preparation,characterization, and antibacterial properties of silver nanoparticles embedded into cellulose aerogels

In this article, highly loaded silver (Ag) nanoparticles with mean diameter of about 7.83 nm were synthesized by reducing Ag ions by NaBH₄ with strong reducibility, and homogeneously embedded into cellulose aerogels without obvious reunion. The as‐prepared nano‐Ag/cellulose (NAC) aerogels maintained nanoporous and multiscale morphology similar to the pure cellulose aerogels, and showed strong antibacterial activities for both Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive). Meanwhile, after the incorporation of Ag nanoparticles, NAC aerogels also displayed more superior thermal stability. Thus, the novel NAC aerogels might be expected to be used as various biomedical applications, especially green heat‐resistant high‐performance antibacterial materials. POLYM. COMPOS. 37:1137–1142, 2016. © 2014 Society of Plastics Engineers