Preparation and properties of multifunctional cotton fabrics treated by phenolic acids

Phenolic acids are found in many plant-based natural antioxidants and are known to offer diverse health-promoting effects such as antimelanogenic, antioxidant, antineoplastic, and bacteriostatic properties. Furthermore, they not only inhibit pathogen growth but also have little toxicity to human beings. Therefore, in this study we treated cotton fabrics with two different phenolic acids, gallic acid (GA) and 4-hydroxybenzoic acid (4-HBA), through a pad-dry cure process, and investigated the properties such as mechanical properties, antibacterial ability, antioxidant ability, etc. Consequently, the phenolic acid treatment did not have significant influence on color, touch, and tensile strength of cotton fabrics. However, it was found that the cotton fabrics treated by both GA and 4-HBA showed high antibacterial ability against Staphylococcus aureus and Klebsiella pneumonia; however, only the GA treated cotton fabrics showed reasonable antioxidant ability.     

Preparation of antibacterial cellulose with a monochloro‐s‐triazine‐based N‐halamine biocide

A novel monochloro‐s‐triazine‐based N‐halamine precursor, 4‐(4‐(5,5‐dimethylhydantoin‐3‐ethylamino)‐6‐chloro‐1,3,5‐triazinylamino)‐benzenesulfonate (HB), was synthesized and characterized by proton nuclear magnetic resonance. The reactive dyes dyeing method was applied to bond HB onto cotton fabrics, and the treated fabrics were confirmed by Fourier transform infrared spectrometer and scanning electron microscope. The chlorinated HB‐treated fabrics showed excellent antibacterial efficacies against Staphylococcus aureus and Escherichia coli O157:H7 and inactivated all inoculated bacteria within 1 min of contact. Interestingly, it was found that the finishing process and following chlorination caused smaller tensile strength loss of cotton fabrics than the traditional pad‐dry‐cure method. Furthermore, the antimicrobial cotton fabrics exhibited good stability and regenerability. Copyright © 2015 John Wiley & Sons, Ltd.     

Development of antimicrobial cotton fabric using bionanocomposites

In order to provide antimicrobial activity to cotton, cotton fabrics were treated by montmorillonite (KSF), montmorillonite–dihydroxy ethylene urea (KSF–MDEU), KSF–chitosan (CS) and KSF–CS–MDEU solutions containing 12.5, 25 and 50 ppm silver ion. The effect of modification on the antibacterial activity of cotton fabrics was also evaluated after 10 cycles of washings. MDEU exhibited better antimicrobial activities after washing process. By using 25 ppm silver, KSF and CS modification solution, good performance in terms of antibacterial activity was obtained. The addition of CS and MDEU increased the whiteness index values of cotton fabrics treated with KSF containing different silver concentrations. The characterization of modified cotton samples was done by Fourier transform infrared spectroscopy, X-ray diffraction analysis, inductively coupled plasma-mass spectroscopy, scanning electron microscopy and thermogravimetric analysis.     

A simple method for determining the total amount of physically and chemically bound water of different cements

A novel environmentally friendly flame-retardant compound, diethyl 3-(triethoxysilanepropyl) phosphoramidate (DTP) was synthesized via a simple one-step procedure with good yield and characterized by FT-IR and ¹H-NMR, ³¹P-NMR and ²⁹Si-NMR. The synthesized compound was coated onto cotton fabrics with different levels of add-ons (5–17 mass%) using the traditional pad-dry-cure method. SEM and XPS were conducted to characterize the surfaces of the coated cotton fabrics. The XPS results showed that DTP was attached to cotton through covalent bond. Cone calorimeter test showed that the cotton fabric treated with DTP became less flammable due to the lower HRR, THR and CO₂/CO ratio. The modified cotton fabrics exhibited efficient flame retardancy, which was evidenced by limiting oxygen index (LOI) and vertical flammability test. Cotton fabrics treated with DTP in 5–17 mass% add-ons had high LOI values of 23–32%. Thermogravimetric analysis results show that the usage of DTP promotes degradation of the cotton fabrics and catalyzes its char formation.     

Preparation and properties of multi-functionalized cotton fabrics treated by extracts of gromwell and gallnut

Extracts from the root of Lithospermum erythrorhizon (gromwell) have been used for many centuries as a natural red dye and crude drugs with excellent performance for wound healing. In particular, shikonin a major constituent of the gromwell colorant is reported to possess antibacterial, antioxidant, anti-inflammatory, antitumor activities, etc. Therefore, we tried to manufacture antimicrobial and antioxidant cotton fabrics for biocompatible clothing materials using the natural stuff and environmentally friendly process. In this study, cotton fabrics were dyed with the colorant extracted from the root of gromwell, and their properties were closely investigated. Consequently, we discovered that the cotton fabrics dyed with the extracts from the root of gromwell showed excellent antioxidant performance as well as antibacterial ability. Also, the functionalities and color fastness were improved by gallnut mordanting and cationization of the cotton fabrics.     

Dihydromyricetin

A study on the efficiency of bio-based compound as stabilizer for linear low density polyethylene (LLDPE) is reported. A water extract from Ampelopsis grossedentata (Dihydromyricetin) is used. Its stabilizing activity is compared with two commercial phenolic antioxidants: methyl gallate (MG) and Irganox 1010. Based on the measurement of the oxidation onset temperature (OOT) of LLDPE/antioxidant samples, it is found that the antioxidant ability of the three kinds of antioxidants is in the following order: DMY > 1010 > MG. The antioxidant ability and thermal decomposition activation energy (E _a) of antioxidants are further examined by thermal gravimetric analysis. The effects of water extraction on the migration resistance of LLDPE/antioxidants are also evaluated by monitoring the OOT change, demonstrating that DMY retained high stability against migration.     

Different methods for β-cyclodextrin/triclosan complexation as antibacterial treatment of cellulose substrates

Two different production ways of antibacterial cotton fabrics by means of triclosan inclusion into a β-cyclodextrin cavity have been compared. On the one hand, triclosan has been dissolved into an aqueous solution of a β-cyclodextrin derivative with the aim of including the antibacterial agent into the cavity before grafting the β-cyclodextrin on a cotton fabric. On the other hand, the same β-cyclodextrin derivative has been grafted onto cotton and, subsequently, the fabric has been immersed into a triclosan water–ethanol solution to allow the inclusion complex formation. The antibacterial properties have been evaluated according to AATCC Test Method 100–1993 before and after two washing cycles at 60 °C. It has been shown that the durability of the antibacterial finishing depends on the production method, obtaining a more durable antibacterial action in case of prior triclosan inclusion followed by grafting. This suggests that the immobilization onto the fiber has affected the cyclodextrin cavity accessibility.     

Preparation and characterization of cotton fabrics with antibacterial properties treated by crosslinkable benzophenone derivative in choline chloride-based deep eutectic solvents

Cotton fabrics with antibacterial properties were prepared by the treatment with 3,3′4,4′-benzophenone tetracarboxylic dianhydride (BPTCD) in a combined process of shaking immersion in dyeing machine and pad-dry-cure. Environmentally-benign choline chloride (ChCl)-based deep eutectic solvents (DESs) were mainly examined as treatment media instead of using organic solvent. The results revealed that cotton fabrics treated with BPTCD in urea-ChCl DES showed a strong ester carbonyl peak in fourier transform infrared (FTIR) analysis, indicating fixation of BPTCD on cotton cellulose. Detailed characterizations of the BPTCD-treated cotton were carried out by FTIR, thermogravimetric analysis, scanning electron microscopy, dye staining, and evaluation of hydrophilicity and strength. The treated fabrics demonstrated a high level of antibacterial characteristics before and after UV irradiation. This indicated that addition of ChCl could enhance antibacterial activity of cotton before UV irradiation. Therefore, use of ChCl-based DES along with BPTCD incorporation provided environmentally-acceptable and economically-feasible treatment process for preparation of novel antibacterial cotton.     

Lycopus europaeus: phenolic fingerprint,antioxidant activity and antimicrobial effect on clinical Staphylococcus aureus strains

Lycopus europaeus L. leaves water extract (LEL) was subjected to phytochemical analysis, and evaluated for its antibacterial and antioxidant effects. Antibacterial activity testing was performed on Staphylococcus aureus clinical strains from catheter-related and skin infections by broth microdilution test. LEL showed bactericidal activity at concentrations from 2500 to 5000 μg/mL against all, including methicillin resistant and polyresistant nosocomial, strains. Antioxidant activity was examined using DPPH and ABTS (11.3 and 9.8 μg/mL, respectively) and by ferric reducing ability of the plasma method (891 μmol AAE/g dry extract). Phytochemical analysis of LEL was performed by LC-DAD-MS/MS. Ten phenolic compounds were identified; two minor compounds (glucopyranosyl rosmarinic acid and sagerinig acid) have not been described in Lycopus yet. The major compounds, considered to be responsible for biological activities detected in the study, were determined as rosmarinic acid (76 mg/g) and luteolin-7-O-glucuronide (23 mg/g). L. europaeus arises from our study as a promising source of antibacterial agent for topical usage.     

Organic–inorganic hybrid silica film coated for improving resistance to capsicum oil on natural substances through sol–gel route

This study concerns the organic–inorganic hybrid coating of silica sol based on dyed cotton, silk and wool fabrics in order to increase the repellence to capsicum oil via adding methyltriethoxysilane, octyltriethoxysilane, hexadec-ltrimethoxysilane or tridecafluorooctyltriethoxysilane (FAS) in the inorganic silica sol. The dyed cotton fabric treated with hybrid silica sol doped with FAS (F-silica sol, FAS 4 %) presents oil-repellent capability, and the contact angles of capsicum oil on the treated cotton, silk and wool fabrics are 98.5°, 111.59° and 122.15°, respectively. A high FAS concentration (20 %) can improve the oil-repellent ability to 5 grades comparing to the untreated fabrics. The color strengths (K/S) of the coated fabrics change slightly, while the maximum absorption wavelengths of the coated fabrics are the same as the untreated fabrics. Although the drape coefficient of cotton fabric is increased to 54 % from 39 % after coated with F-silica sol, the effect is not significant. Compared to the weight gain rate of untreated cotton, silk and wool samples (1.89, 1.23 and 2.38 %), the weight gain rate of the cotton, silk and wool samples coated with F-silica sol are 6.99, 4.76 and 7.69 %, respectively. The calculated sol–gel weight gains (5.10, 3.53 and 5.31 %) of coated fabrics indicate that the silica coating is subsistent on the fiber surfaces.     

Antibacterial cotton fabric prepared by a “grafting to” strategy using a QAC copolymer

Quaternary ammonium compounds (QACs) have outstanding antimicrobial effect, but covalent immobilization of plentiful QAC onto cotton fiber surface to realize a durable function remains a challenge. Herein, a quaternary ammonium monomer, [2-(methacryloyloxy) ethyl] trimethylammonium chloride (DMC) was co-polymerized with methyl acrylate (MA) to prepare an antibacterial copolymer, poly(DMC-co-MA). To graft the copolymer with an improved grafting efficiency, cotton fabric was treated using carboxymethyl chitosan (CMC) to establish an amino-functionalized fiber surface first. This treatment allows the amidation reactions between the amino groups and the pendant ester groups in the poly(DMC-co-MA) to take place, achieving a durable anionic polymer coating onto the fiber surfaces with remarkably antibacterial effect. Characterization results indicated that when DMC/MA monomer ratio was 100:1, the resulting copolymer endows the modified cotton fabric with antibacterial capability that inactivates all Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Even after 50 laundering cycles, more than 98.0% of the antibacterial rate could still be retained. Moreover, the wearing comfort properties such as softness, water absorption and air permeability of the finishing cotton fabrics have been insignificantly changed by comparing to the untreated cotton fabric.

     

Effect of processing on the release of phenolic compounds and antioxidant activity during in vitro digestion of hulless barley

Hulless barley contains phenolic compounds and possesses various antioxidant activities. To clarify the effects of thermal processing and in vitro digestion on the release of phenolic compounds in hulless barley, we studied the phenolic components and antioxidant activities of hulless barley after steaming, roasting processes, and in vitro digestions. Both total phenolic content (TPC) and total flavonoid content (TFC) in raw hulless barley (HB, 4.14 mg/g DW and 1.53 mg/g DW, respectively) were higher than that of steamed hulless barley (SHB) and roasted hulless barley (RHB). In vitro digestion significantly released more ferulic acid from its bound form, but hydrolyzed some amount of flavonoid (luteolin). Chrysoeriol-7-O-glucouronide was significantly detected (412.13 µg/g DW in HB, 382.19 µg/g DW in SHB, and 396.91 µg/g DW in RHB) in all three hulless barley. The total released content of phenolic compounds obtained from each phase after digestion reached to 46% and 45% for SHB and RHB, which was higher than that in the HB (41%). The antioxidant assay (via DPPH and ABTS free radical scavenging assays) indicated that the capacity of HB was obviously higher than that of SHB and RHB in undigested group. For digested group, the ABTS⁺ assay order was following, undigested > oral > small intestine > gastric > large intestine. The DPPH assay results indicated the antioxidant capacity as the order of undigested > oral > gastric > large intestine. Correlation analysis showed that ferulic acid, chrysoeriol-7-O-glucouronide, luteolin, chrysoeriol, and luteolin-7-O-glucouronide contributed to the antioxidant activities. Hierarchical cluster analysis (HCA) grouped samples accordingly. Roasting process could be considered as a better daily thermal treatment for hulless barley than steaming in terms of phenolic compounds and their antioxidant activities.     

Developing Novel Antimicrobial and Antiviral Textile Products

In conjunction with an increasing public awareness of infectious diseases, the textile industry and scientists are developing hygienic fabrics by the addition of various antimicrobial and antiviral compounds. In the current study, sodium pentaborate pentahydrate and triclosan are applied to cotton fabrics in order to gain antimicrobial and antiviral properties for the first time. The antimicrobial activity of textiles treated with 3 % sodium pentaborate pentahydrate, 0.03 % triclosan, and 7 % Glucapon has been investigated against a broad range of microorganisms including bacteria, yeast, and fungi. Moreover, modified cotton fabrics were tested against adenovirus type 5 and poliovirus type 1. According to the test results, the modified textile goods attained very good antimicrobial and antiviral properties. Thus, the results of the present study clearly suggest that sodium pentaborate pentahydrate and triclosan solution-treated textiles can be considered in the development of antimicrobial and antiviral textile finishes.     

Ultrasound-assisted ozone bleaching of cotton

In this study, the effects of ultrasound on ozone treatment processes for bleaching cotton fabrics were investigated and compared with the conventional hydrogen peroxide bleaching process (60 °C over 90 min). Two ultrasonic + ozone treatments of cotton fabric samples were carried out: (1) ozone in an ultrasonic homogenizer (UH) and (2) ozone in an ultrasonic bath. Ozone dosages, temperature and time variations were determined with both ozone-ultrasonic bleaching processes. Whiteness, yellowness, weight, tensile strength properties, FTIR (ATR) spectra and visual appearance, via scanning electron microscopy of treated cotton fabrics as well as chemical oxygen demand (COD) of bleaching effluents, were investigated. It was concluded that the ozone + UH process, conducted for 30 min at 30 °C, produced closely equivalent values of cotton fabric whiteness and yellowness to the classic peroxide bleaching process, with slightly less weight loss, dramatically less COD in the process effluent (29 mg/l for ozone-UH vs. 4,316 mg/l for classical peroxide treatment), and without causing any adverse and/or detrimental effects on loss of fabric strength or elongation of the cotton fabrics. The ozone-UH process also leads to time and energy savings with much less environmental impact. Consequently, the combination of ozonation plus UH carried out at 30 °C over 30 min can be used successfully for cotton bleaching instead of the classic hydrogen peroxide bleaching process.     

Improving anti-UV performances of cotton fabrics via graft modification using a reactive UV-absorber

In this study, a reactive UV-absorber (UV-DTHM) was synthesized by the reaction of 2,4-dihydroxy benzophenone with 2,4,6-trichlorotriazine and showed excellent ultraviolet absorption property and good thermostability. Using pad-dry-steam process, UV-DTHM was grafted into bleached cotton fabric through the covalent surface modification of the cotton fibers. The optimal finishing conditions, such as amount of the catalyst, temperature of the finishing bath, steaming time and concentration of UV-DTHM, were discussed. The UV-DTHM-modified cotton fabrics were characterized by FTIR spectroscopy, SEM and ultraviolet protection factor (UPF), etc. It was found that the highest value of UPF, 46.5, can be obtained in the conditions of 60 °C, 2 % owf UV-DTHM and dipping 60 min, and that UPF remained constant and was still more than 30 after thirty consecutive launderings, which showed strong anti-UV performance and fairly good durability.     

Effect of zinc oxide on flame retardant finishing of plasma pre-treated cotton fabric

An organic phosphorus compound (flame retardant agent, FR) in combination with a melamine resin (crosslinking agent, CL), phosphoric acid (catalyst, PA) and zinc oxide (co-catalyst, ZnO/nano-ZnO) imparted effective and durable flame retardant properties. Also, atmospheric pressure plasma jet was applied as pre-treatment to improve post-finishing (flame retardant finishing) on cotton fabrics. In the present paper, surface morphology, chemical structure analysis, combustibility and mechanical properties of plasma pre-treated cotton fabrics subjected to flame-retardant treatment were investigated. Surface morphology of treated cotton specimens showed roughened and wrinkled fabric surface with high deposition of the flame retardant finishing agent, which was caused by the plasma etching effect and attack of acidic FR. The FTIR-ATR spectra for the treated cotton specimens showed some new characteristic peaks in chemical structure, interpreted as carbonyl bands, OH stretching vibration, COO⁻ stretching vibration, CH₂ rocking band and CH₃ asymmetric and CH₂ symmetric stretching. Moreover, FR-CL-PA-treated specimens showed remarkable flame-retardant property, which was further improved by the plasma pre-treatment and ZnO/nano-ZnO co-catalyst. However, flame-retardant-treated cotton specimens had poor mechanical strength when compared with control sample, resulting from side effects of the crosslinking agent used, while plasma pre-treatment and ZnO/nano-ZnO co-catalyst may compensate for the reduction in tensile and tearing strength caused by flame-retardant agents.     

Tapping the Bioactivity Potential of Residual Stream from Its Pretreatments May Be a Green Strategy for Low-Cost Bioconversion of Rice Straw

In this study, it was found that the residual stream from pretreatments of rice straw exhibited high antioxidant activity. Assays based on the Folin–Ciocalteu colorimetric method confirmed that the residual stream contained large amounts of phenolic compounds. Three antioxidant assays were employed to evaluate the bioactivity of the residual stream. Strong linear correlations existed among the release of phenolic compounds, saccharification efficiency, and antioxidant activity. The alkaline pretreatment provided a much greater release of phenolic compounds, especially phenolic acids, compared to the acid pretreatment, and consequently, it had stronger linear correlations than the acid pretreatment. Antibacterial experiments demonstrated the ability of the phenolic compounds in the residual stream to inhibit the growth of microorganisms, indicating the potential of these compounds as antimicrobial agents. To discuss the possibility of the co-production of antimicrobial agents and biofuels/biochemicals, both acid and alkaline pretreatments were optimized using response surface methodology. Under the optimal conditions, 285.7 g glucose could be produced from 1 kg rice straw with the co-production of 3.84 g FA and 6.98 g p-CA after alkaline pretreatment. These results show that the recovery of phenolic compounds from the residual stream could be a green strategy for the low-cost bioconversion of rice straw.     

UV protective textiles by the deposition of functional ethylcellulose nanoparticles

Ethylcellulose (EC) nanoparticles have been widely investigated for their use as drug delivery systems. However, their application on the textile field has been hardly studied. In this work, the use of EC nanoparticles as nanocarriers of active or lipid soluble compounds and their subsequent deposition on cotton textile is proposed in order to obtain functional textiles. A UV protective textile has been obtained after deposition of EC nanoparticles loaded with a liposoluble UV filter on cotton fabrics. The EC/cotton affinity and the attachment mechanism of EC nanoparticles on cotton substrate was studied by means of thermal behaviour evaluation, estimation of adhesion work (W_A) and wash resistance tests. It is proposed that during EC nanoparticles deposition on cotton fabric, entanglement of polymeric chains is favoured, thus improving adhesion of EC nanoparticles on cotton substrate. The functionality of cotton textile was assessed by ultraviolet protection factor (UPF) measurements, showing a high UPF value (UPF = 45). Evaluation of UPF as a function of washing cycles were carried out on treated cotton fabrics. Washed fabrics still provided good UV protection (UPF ≥ 25), evidencing the presence of nanoparticles after washing cycles and the durability of the conferred functionality.     

UV-induced graft polymerization of acrylamide on cellulose by using immobilized benzophenone as a photo-initiator

Photo-active moiety, benzophenone, was incorporated onto cotton fabrics by using butyl tetracarboxylic acids (BTCA). Then, grafting of polyacrylamide on the cotton fabrics was performed by exposing the fabrics to longer UV wavelength irradiation. The chemical structure and thermal properties of the polyacrylamide grafted cotton fabrics were investigated by SEM, FTIR, XRD, and TGA, and the results verified the successful grafting of polyacrylamide on cotton fabrics. Also, it was observed that active chlorine contents were created on the polyacrylamide grafted cotton fabrics through simple chlorination process, and the chlorine treated cotton fabrics showed excellent antibacterial abilities like the powerful cyclic amide halamines.     

Identification and in vitro antioxidant activities of phenolic compounds isolated from Cynoglossum cheirifolium L.

In an extensive search for bioactive compounds from plant sources, the quantitative and qualitative characterisation of the compounds present in Cynoglossum cheirifolium extracts was studied. Total phenolic and flavonoid contents were determined by spectrophotometric techniques. In vitro antioxidant and radical scavenging profiling was determined through DPPH^? scavenging activity and Ferric reducing antioxidant power (FRAP). Our study showed that leaves produce more phenolic compounds, followed by flowering aerial part. The butanolic fraction obtained from leaves extract exhibited the highest total phenolics (78.65 ± 3.58 mg GAE/g DW) and flavonoids (22.15 ± 4.66 mg CE/g DW). In contrast, this fraction displayed the highest DPPH^? scavenging ability with IC₅₀ values of 0.06 ± 0.003 mg/mL. The RP-HPLC-PDA analysis of phenolic compounds from leaves of C. cheirifolium lets to identify: rosmarinic acid, ferulic acid, caffeic acid, p-coumaric acid, syringic acid, sinapic acid and rutin. The obtained results indicate that this plant represent a valuable source of natural antioxidants.