Antimicrobial functionalization of poly(ethylene terephthalate) fabrics with waterborne N‐halamine epoxides

A water dispersible terpolymer of [2‐(methacryloyloxy)ethyl]trimethylammonium chloride, glycidyl methacrylate and hydantoinyl acrylamide was synthesized and coated on poly(ethylene terephthalate) fabrics through a pad‐dry‐cure procedure. The coatings were rendered biocidal upon exposure to dilute household bleach solution. The halogenated fabrics exhibited great antimicrobial functionality with about six logs inactivation of S. aureus and E. coli O157:H7 within only two min of contact time. Moreover, the coatings were found to be very stable against repeated washings and UVA light exposure. It was shown that [2‐(methacryloyloxy)ethyl]trimethylammonium monomer is very useful in preparing waterborne N‐halamines which can impart rechargeable, effective, and stable antimicrobial coatings to poly(ethylene terephthalate) fabrics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43088.     

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     

Antimicrobial N‐halamine coatings synthesized via vapor‐phase assisted polymerization

An N‐halamine monomer, 3‐allyl‐5,5‐dimethylhydantoin (ADMH), was synthesized by a Gabriel reaction of 5,5‐dimethylhydantoin and 3‐bromopropene. Antimicrobial coatings of poly[1‐(4,4‐dimethyl‐2,5‐dioxoimidazolidin‐1‐methyl)ethylene] were prepared on plasma‐treated PET fabrics via a vapor‐phase assisted polymerization (VAP) process using gasified ADMH as monomer. The coatings endow the PET fabrics with an antimicrobial efficiency greater than 80% for both Escherichia coli and Staphylococcus aureus after chlorination of the N‐halamine polymer with dilute bleach solution. The obtained antimicrobial effect has remarkable durability that can bear over 30 times of stringent laundering tests. Compared with other antimicrobial finishing methods, the VAP methodology offers great advantages in needless of organic solvents and small consumption of monomer. It has potential applications in a wide variety of fields such as hygienic clothing, underwear, socks, and medical textiles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41824.     

Treatment of melamine formaldehyde fibers for decontaminating biological and chemical warfare agents

The demand for protection against biological and chemical warfare agents has increased the need for unique protective materials. N‐halamines are superior candidates for this task by having rapid inactivation rates against a broad range of microorganisms and the ability to oxidize some pesticides and warfare agents to reduce their toxicity to humans. Thus, the design of N‐halamine materials having fibrous structure, high halogen loading capacity with enhanced stability, and being relatively inexpensive is very important. This study investigated the effect of acid treatment on the chlorine loading and stability of a commercial flame retardant melamine formaldehyde (MF) fiber to introduce biocidal and detoxifying properties. The fibers formed into a web were treated with diluted sulfuric acid (H₂SO₄) under various conditions. The fiber webs were chlorinated with household bleach, and the stability of bound chlorine was investigated. The treated fabrics have been tested against a Gram‐negative bacterium and a warfare stimulant. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42799.     

Synthesis and application to cellulose of reactive dye precursor of anti‐bacterial N‐halamine

To achieve textile dyeing and functional finishing in one process, a bleach‐resistant reactive dye precursor to anti‐bacterial N‐halamine was synthesised by reacting a type of dichlorotriazine reactive dye with 4‐amino‐2,2,6,6‐tetramethylpiperidine. The synthesised compound, which can be transformed to an N‐halamine molecule by exposure to dilute bleach solution, was used to dye cotton fabrics. After exposure to a dilute sodium hypochlorite solution, dyed cotton fabrics showed excellent anti‐bacterial properties against Staphylococcus aureus and Escherichia coli O157:H7, facilitating a ca. 6‐log reduction in bacteria within a short period of contact. Compared with the dichlorotriazine reactive dye, the reactive dye precursor demonstrated comparable dyeing properties including exhaustion and fixation values. No differences in rub fastness, wash fastness or bleach fastness were detected between fabrics dyed with, respectively, dichlorotriazine reactive dye and the reactive dye precursor to N‐halamine.     

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.     

Sand/charcoal N‐halamine blends for water treatment

N‐halamine polymeric material based on cellulose extracted from an agricultural waste (rice straw) was blended with sand/charcoal for disinfection purposes. The presence of N‐halamine between sand/charcoal particles in water filters prevents internal bacterial growth and kills filtered cells especially in the deep and lower parts of the filters. N‐halamine was blended with sand/charcoal with different ratios, 1:3, 1:2, 1:1, 2:1, and 3:1, and their antimicrobial activity was evaluated using different methods such as agar plate, agar blend, stirred flask, and column methods. Increasing the ratio of the cellulosic N‐halamine provides further filtration and disinfection action in water in addition to securing a clean medium between sand/charcoal particles especially in columns as models for water filters. The ratio 1:1 (sand/charcoal: N‐halamine) was found to be suitable for producing a recyclable water filter and recyclable water purification unit based on sand/charcoal‐ N‐halamine blends. POLYM. COMPOS., 35:2137–2143, 2014. © 2014 Society of Plastics Engineers     

Preparation,characterization, and antibacterial activities of quaternarized N‐halamine‐grafted cellulose fibers

A viable method for coating of cellulose fiber with quaternarized N‐halamine is reported in this article. The use of quaternary ammonium salt group in combination with N‐halamine group can reinforce the antibacterial activity. The chemical structure of as‐synthesized N‐halamine precursor 4‐(Bromo‐acetic acid methylester)‐4‐ethyl‐2‐ oxazolidinone (BEO) was characterized by ¹H‐NMR. The cellulose fibers were characterized by Fourier transform infrared spectra and X‐ray photoelectron spectra. The spectra data confirmed that the quaternarized N‐halamine‐grafted cellulose fibers were successfully obtained. The antibacterial properties of functional fibers were challenged with both Gram positive and Gram negative bacteria. The antibacterial tests and showed that the as‐prepared antibacterial cellulose fibers exhibited powerful and rapid bactericidal performance against both Gram negative E. coli and Gram positive S. aureus. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42702.     

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.     

Preparation and characterization of a temperature‐sensitive nonwoven poly(propylene) with increased affinity for guest molecules

A temperature‐sensitive hydrogel with the capability of inclusion complex formation with guest molecules was successfully grafted onto the surface of nonwoven polypropylene (nonwoven PP). This was carried out by the use of N‐isopropylacrylamide monomer and a modified cyclodextrin (acrylamidomethyl‐β‐cyclodextrin (β‐CD‐NMA)). Fourier‐transform infra red (FT‐IR) and elemental analyses confirmed the presence of poly(N‐isopropylacrylamide) (PNIPAAm) and β‐CD‐NMA components on the surface of the textile. Equilibrium swelling ratio measurements showed that the grafted hydrogel maintained its temperature‐sensitive property compared to a nongrafted hydrogel. The effect of β‐CD‐NMA and crosslink agent concentrations on the grafting yield was studied. The β‐CD‐NMA content into the PNIPPAM‐ β‐CD‐NMA grafted nonwoven PP (PNIPAAm‐β‐CD‐NMA‐PP) was estimated by FT‐IR through a new procedure. The estimated amounts of β‐CD‐NMA in PNIPAAm‐β‐CD‐NMA‐PP were determined to be 0.9, 1.9 mg g^?1 for 0.019M and 0.049M concentrations of β‐CD‐NMA in monomer solution, respectively. The PNIPAAm‐β‐CD‐NMA‐PP showed a remarkable increase in absorbance affinity of 8‐anilino‐1‐naphthalenesulfonic acid ammonium salt at 20°C from 0.93 to 3.33 µmol g^?1 compared to PNIPAAm‐PP. Furthermore, the results showed a temperature‐sensitive loading affinity for PNIPAAm‐β‐CD‐NMA‐PP in absorbance of guest molecules due to the presence of β‐CD‐NMA. The use of hydrophobic guest molecules such as fragrance oils and antibiotics in modified fabrics can provide new applications in textile and pharmaceutical industry. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40497.     

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     

Biocidal nanofibers via electrospinning

To achieve biocidal properties, a cyclic N‐halamine precursor, 7,7,9,9‐tetramethyl‐1,3,8‐triazaspiro[4.5]‐decane‐2,4‐dione (TTDD), was synthesized and introduced into nanosized polyacrylonitrile fibrous mat by an electrospinning technique. It was rendered antimicrobial by exposure to dilute hypochlorite solution. Synthesis routes and characterization data are presented. Scanning electron microscopy (SEM) demonstrated that the ultrafine fiber possessed average diameter 414 nm (from 240 to 650 nm). The chlorinated nanofibrous composites provided about 4.9 log reductions of both Gram‐positive bacteria Staphylococcus aureus (ATCC 6538) and Gram‐negative bacteria Escherichia coli O157:H7 (ATCC 43895) within 5 min of contact time. This is indicative of promising possible applications in the filtration of water and air. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Properties of PHMS‐g‐p [butylacrylate (BA)‐N‐hydroxyl‐methyl acrylamide (NMA)] graft copolymer emulsions

Emulsion graft copolymerization of poly(hydrogenmethylsiloxane) (PHMS) and butyl acrylate (BA) in the presence of functional comonomer N‐hydroxyl‐methyl acrylamide (NMA) was conducted by batch emulsion copolymerization to modify the properties of polysiloxane. Morphology of graft copolymer particles was characterized by transmission electron microscopy. The effect of polymerization method, PHMS content, initiator concentration, and NMA content on stability of emulsion, morphology, size of particle, and rheological properties were investigated. It has been found that stability of emulsion is better by semicontinuous emulsion polymerization than that of batch emulsion polymerization and it increased with increasing PHMS‐NMA concentration. Increasing PHMS concentration and NMA concentration, the particle size and the viscosities increase. The property of resistance to electrolytes of graft copolymer emulsions and swelling property of film were also discussed. Results showed PHMS‐g‐P [butylacrylate (BA)‐N‐hydroxyl‐methyl acrylamide (NMA)] graft copolymer emulsion has good resistance to electrolytes and the water absorption of its film increases with increasing BA‐NMA content grafted onto PHMS. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2209–2217, 1999     

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.     

Effect of a methyl substituent in the polymerization–crosslinking treatment of cotton with NMMA and NMA

An estimation of structures of reagent residues in cotton fabrics treated with N-methylolmethacrylamide (NMMA) and N-methylolacrylamide (NMA) and comparison of textile performance of the NMMA–cotton and NMA–cotton provide the basis for insight into the structure–performance relationship in these fabrics. The α-methyl substituent, which constitutes the difference between NMMA and NMA, accounts for an altered composition of reagent residues in the treated cotton. The more attractive balance of strength–abrasion resistance with resilience for the NMMA–cotton seems to be a result of a lower degree of covalent crosslinking, which appears compensated by a higher elastic modulus in the NMMA network polymer.     

Antibacterial N‐halamine coating on cotton fabric fabricated using mist polymerization

3‐Methylallyloxy‐5,5‐dimethylhydantoin (MH), an methacrylate monomer containing N‐halamine moiety, was synthesized by 5,5‐dimethylhydantoin (DMH) and methacryloyl chloride. Antimicrobial coating of poly[1‐methyl‐1‐(4,4‐dimethyl‐2,5‐dioxoimidazolidin‐carbonyl)ethylene] (PMH) was prepared on cotton fabrics via “mist polymerization” using MH as monomer. The coating gave the cotton fabric with efficient antibacterial function with remarkable durability. In the antibacterial tests, the bacteriostatic reduction rate is greater than 99.78%, and can be maintained over 99.00% even after 30 washing cycles. Compared with other antimicrobial technologies, mist polymerization offers advantages such as achieving antimicrobial function by small consumption of monomer, forming coatings on single‐side of the fabrics, and minimizing the damages on the original properties of cotton during the finishing process. It can be applied in a wide variety of textile products such as sportswear, underwear, socks, and medical textiles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44897.     

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.     

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     

Metabolomic profiling can differentiate between bactericidal effects of free and polymer bound halogen

The effects of two halogenated compounds (sodium hypochlorite and N‐halamine polymers) on the Escherichia coli metabolome were investigated. Changes in the intracellular metabolite pools of bacterial cells treated with different formulations of these compounds were analysed using FTIR (Fourier Transform Infra Red) spectroscopy and LC‐MS (Liquid Chromatography‐Mass Spectroscopy). Principal component analysis was used to generate metabolic profiles of the intracellular metabolites to investigate the effect of sublethal concentrations on the metabolome of treated cells. The effect of treatment with sodium hypochlorite was quantitatively dependent on the exposure time. The resulting metabolic profiles supported our previous hypothesis that the mode of action of some halogenated compounds, such as N‐halamine polymers, can be initiated by release of halogen ions into the aqueous environment, in addition to direct contact between the solid polymer material and the bacterial cells. Moreover, the metabolic profiles were able to differentiate between the effect of free and polymer‐bound halogen. Our metabolomic approach was used for hypothesis generation to distinguish apparently different bactericidal effects of free and polymer‐bound halogen. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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.