Characterization of conductive poly(acrylonitrile-<Emphasis Type="Italic">co</Emphasis>-vinyl acetate) composites: Matrix polymerization of pyrrole derivatives

In this study, poly(acrylonitrile-co-vinyl acetate) (P(AN-co-VAc)) composite films were prepared by chemical polymerization of pyrrole(Py), N-methyl pyrrole (NMPy) and N-phenyl pyrrole (NPhPy) with cerium(IV) [Ce(IV)] on P(AN-co-VAc) matrix. An increase was observed in the absorbances of CN ring stretching vibration (1451 cm⁻¹) by introducing pyrrole (Py) derivatives on P(AN-co-VAc) matrix. The nitrile (CN) and carbonyl (C=O) groups played a significant role on the interactions with cationic sites of Py derivatives. Conductivity was increased in the presence of carbonyl (C=O) groups due to their additional negative charges on P(AN-co-VAc) matrix compared to PAN. Poly(N-Phenyl Pyrrole) (PNPhPy) exhibited higher dielectric constant and AC conductivity in the frequency range between the 10⁻²–10⁷ Hz. The TGA results exhibited shifts of peak to higher temperatures by the presence of Py derivatives by increasing the weight loss %.     

<Emphasis Type="Italic">In situ</Emphasis> deposition of silver nanoparticles on the cotton fabrics

A novel method was developed to prepare the antibacterial cotton fabrics through in situ deposition of silver nanoparticles on the cotton fabrics by the reduction of Ag⁺ without any reductant and dispersant. The data showed that by immersing the cotton fabrics in 160 mM AgNO₃ solution at 90 °C, the amount of silver nanoparticles was increased from 0.6890 to 1.3561 mg per gram of fabrics with the increase of reaction time from 10 to 50 min. The obtained cotton fabrics showed excellent antibacterial activity and laundering durability, in which the bacterial reduction was still 98.5 and 94.3 % to Escherichia coli and Staphylococcus aureus, respectively, even after the fabrics were washed for 20 cycles. Thus, this facile in stitu reduction method without any other reducers or stabilizers may bring a promising and green strategy to produce functional cotton fabrics.     

Effects of fabric surface energy on human thermophysiological responses during exercise and recovery

The present paper reports a study on influences of fabric surface energy of cotton and polyester garments on clothing microclimates and human thermophysiological responses during intermittent exercise and recovery. Eight healthy males wearing the garments prepared performed exercises and rest according to the following protocol: rest for 30 min, run on treadmill for total 60 min of three sessions with different intensity and duration, and then sit quietly for 30 min for recovery, all at 30 °C and relative humidity of 30 %, while the microclimate humidity (H _mc ) and temperature (T _mc ), the clothing outside surface humidity (H _co ) and temperature (T _co ), the skin temperatures and ear canal temperature (T _{ear_canal} ) were measured. The garments are made of: (a) hydrophilic and hydrophobic cotton knitted fabrics, and (b) hydrophilic and hydrophobic polyester knitted fabrics. During and after exercise, for cotton, hydrophilic garment resulted in significant lowerΔH _mc , ΔH _co , ΔT _mc during recovery, higher , lowerΔT _{ear_canal} andΔT _forehead . For polyester, hydrophilic garment resulted in significantly lowerΔH _co , ΔT _co , higher , higherΔT _forehead during E1, E2 and recovery session but lower during E3. In summary, surface energy of cotton garments had significant influences on human thermophysiological responses during exercise and recovery, and hydrophilic cotton garment was better than hydrophobic one to reduce heat stress. Surface energy of polyester garments had influences of lower significance, and hydrophilic garment appeared better than hydrophobic garment.     

Synthesis of ZnO nanoparticles by PNP and its application on the functional finishing of cotton fabrics

This paper presents a facile and novel approach for the synthesis of ZnO nanoparticles in aqueous solution based on a one-step reaction between a modified hyperbranched polymer (PNP) and zinc nitrate. The prepared ZnO nanoparticles polymeric hybrid was characterized and its antibacterial activity was investigated. The results indicated that the ZnO nanoparticles have an average size about 6 nm and well dispersed in aqueous medium. The minimum inhibitory concentration (MIC) of them was 20 ppm and 60 ppm against S. aureus and E. coli, respectively. For the functional finishing of cotton fabrics by these ZnO nanoparticles, a microwave assisted in situ fabrication method was employed. Scanning electron microscope (SEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) measurements confirmed that the ZnO nanoparticles in situ generated in cotton fabrics successfully. Fourier transform infrared (FT-IR) spectroscopic investigation demonstrated that the ZnO nanoparticles were fixed on the cotton fibers by PNP. The treated cotton fabrics exhibited excellent UV protective properties and antibacterial activities. When ZnO content of cotton fabric was 1.49 %, the UPF value of treated cotton fabric exceeded 125 and the bacterial reduction rate against S. aureus and E. coli reached 99.97 % and 98.40 %, respectively.     

Study on oil adsorption/desorption kinetics and polymer network parameters of poly(lauryl methacrylate-<Emphasis Type="Italic">co</Emphasis>-hydroxyethyl methacrylate)

In the present work, oil adsorption, desorption, and resorption of poly(lauryl methacrylate-co-hydroxyethyl methacrylate) P(LMA-co-HEMA) were evaluated with different oils by a gravimetric method. Adsorption kinetics were modeled using pseudo-first-order and pseudo-second-order equations. Polymer network parameters of P(LMA-co-HEMA) regarding average molecular weight (Mc) between two crosslink piontss can be calculated by oil absorbency at equilibrium (Q _e ), the solubility parameter (δ) and polymer-solvent interaction parameter (χ) with Flory-Huggins relation. The results showed pseudo-second-order model has a better fit to the oil adsorption kinetic data The desorption can be analyzed by fitting a prediction of exponential-like decay to the deswelling curves. A typical oil desorption exhibited two stages: a burst release driven by concentration gradient, and a slow release controlled by diffusion and the elastic recovery of polymer networks. For reusability, the resorption behavior of P(LMA-co-HEMA) was also investigated. It was worth noting that oil resorption was faster than the first adsorption due to potential passages. Moreover, the adsorption capacity was not significantly changed after regeneration.     

Aroma finishing of PET fabrics with PVAc nanoparticles containing lavender oil

A durable aroma finishing for PET fabric was carried out by adopting poly(vinyl acetate) (PVAc) nanoparticles containing lavender oil (LO) in core. Relatively small size of PVAc nanoparticles (ca. 244 nm of mean particle diameter) was expected to resist the frictional destruction of the particles, which is frequently observed in cases of microcapsules. PVAc nanoparticles containing LO in core were prepared by emulsification-diffusion method and their application as an aroma releasing agent for PET fabrics was assessed through the observation of releasing profiles of LO in ethanol for experimental acceleration. Melamine-formaldehyde (MF) microcapsules containing LO were also prepared and treated on fabrics for comparison. PVAc nanoparticles treated on PET fabric showed higher initial releasing amount, which was ascribed to the enhanced surface area. After 2 days of releasing, PET fabric treated with PVAc nanoparticles showed slower and more stable releasing profile and reached about 12 ppm of cumulative release after 16 days, which was under two thirds of that with MF microcapsules. PVAc nanoparticles can be used as an agent for durable aroma finishing of PET fabrics.     

Multifunctional polyester fabric using a multicomponent treatment

In this study, multifunctional polyester fabrics with the features of self-cleaning, water and stain repellency, and thermal stability were prepared utilizing a multicomponent system. To this end, both unmodified and alkaline-hydrolyzed modified fabrics were treated with nano TiO₂/citric or maleic acid/sodium hypophosphite/polysiloxane and triethanolamine via a pad-dry-cure method. Surface morphology and color variation of the samples were studied utilizing field emission scanning electron microscopy (FESEM) and CIE-Lab system, respectively. Also, energy-dispersive X-ray (EDX) analysis indicated the content of Ti, P and Si on the surface of fabrics. Thermal stability of the specimen was scrutinized through thermal gravimetric analysis (TGA) and char yield. Both hydrolysis treatment and silicone softener increased the uptake of the nanoparticles. Also, in a comparison between the utilized carboxylic acids, citric acid demonstrated superior features. Generally, the treated fabrics showed desirable self-cleaning and stain repellency with some enhanced thermal stability.     

Effect of Silver Particle size on color and Antibacterial properties of silk and cotton Fabrics

In this study silver nanoparticles with different particle sizes and hence colors were synthesized on silk and cotton fabrics through reduction of silver nitrate. Particle sizes of the silver colloids were measured by dynamic light scattering (DLS). The structure and properties of the treated fabrics were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and UV-Vis reflectance spectroscopy. Various characteristics of the treated fabrics including antibacterial activities against a Gram positive (Staphylococcus aureus) and a Gram negative (Escherichia coli) bacteria, color effect, wash and light fastness, water absorption, fabric rigidity, and UV blocking properties were also assessed. The results indicated that the treated fabrics displayed different colors in the presence of silver nanoparticles with different particle sizes and exhibited good and durable fastness properties. Also, the size of the silver particles had a tangible effect on antibacterial activity of treated fabrics and its antibacterial performance was improved by decreasing the size of particles. Moreover, this process imparted significantly UV blocking activity to fabric samples.     

Optimization of enzymatic hydrolysis of waste cotton fibers for nanoparticles production using response surface methodology

A Box-Behnken design (BBD) was used for optimization of enzymatic hydrolysis of waste cotton fibers in order to obtain finest cellulose particles. The effect of three factors including hydrolysis time (h), substrate concentration (g/l) and enzyme loading (%) were investigated. The median size of the hydrolyzed particles was defined as the response function of the design. Results of BBD were subjected to analysis of variance (ANOVA) and a quadratic polynomial equation was developed for predicting the particle size. According to the fitted model, the optimal conditions i.e. hydrolysis time, substrate concentration and enzyme loading were suggested as 175 h, 5 g/l and 2.3 %, respectively. The suspension prepared under optimum conditions was subjected to ultrasonic treatment, and the resulted stable suspension of cellulose nanoparticles was characterized. It was found that these nanoparticles are spherical and most of them are in the range of 40–90 nm. The enzymatic and ultrasonic treatments caused an increase in the crystallinity and a decrease in the degree of polymerization of cotton.     

Effects of starch composition and type of non-solvent on the formation of starch nanoparticles and improvement of curcumin stability in aqueous media

In this study, we evaluated the effects of amylopectin/amylose ratio and non-solvent type on starch nanoparticle formation including the average particle size, polydispersity index, size distribution, and nanoparticle morphology using dynamic light scattering (DLS) and scanning electron microscopy (SEM). The most uniform particles were obtained from normal corn starch with ethanol. The average particle size was 98.8 ± 1.8 nm using DLS while combination of size distribution study and SEM images showed that particle size ranged between 60 and 90 nm. A bimodal distribution was observed with two defined groups of nanoparticles when waxy corn starch (Amioca) was nanoparticulated with ethanol. SEM images of freeze dried samples and DLS size distribution curves of fresh samples showed that high amylose starch including Hylon V and Hylon VII gave uniform, spherical and small nanoparticles in the size range of 20–60 and 15–50 nm, respectively. The smallest nanoparticles were fabricated by precipitation with methanol, followed by ethanol and the largest nanoparticles were formed using acetone. Re-dispersion of nanoparticles was good when nanoparticles were fabricated using ethanol and acetone especially for Amioca, whereas redispersion of samples in aqueous PBS solution, precipitated using methanol was difficult especially in the case of Hylon VII. Stability of curcumin in the presence of 1 mg/ml native starch nanoparticles was much higher (83.7 ± 3.1%) than curcumin in phosphate buffered saline at pH 7.0 (5.5 ± 1.5%) over 10 days at ambient temperature. Interaction between iodine-potassium iodide solution and starch nanoparticles showed that the helical structures of amylose and amylopectin molecules remain in the nanoparticles and curcumin may interact with these helical structures giving it the stability which is not observed in water.     

Cutinase treatment of cotton fabrics

Our study proposes an enzymatic scouring method for cotton fabrics using the enzyme cutinase. We established cutinase treatment conditions for cotton fabrics from their relative activity at different pH levels, temperatures, enzyme concentrations, and treatment times. Weight loss, moisture regain, K/S value, tensile strength, and SEM micrographs of cotton fabrics were analyzed. We determined the optimum cutinase treatment conditions to be as follows: pH of 9.0, temperature of 50°C, cutinase concentration of 100 %, and a treatment duration time of 60 min. We discovered that this cutinase treatment hydrolyzed the cuticle of cotton fabrics. The cutinase treatment did not decrease the moisture regain and the K/S value. The optimum concentrations of Triton X-100 and calcium chloride, which were used as auxiliaries for cutinase treatment, were found to be 0.5 % (v/v) and 70 mM, respectively. Some cracks were observed on the surface of the cotton fibers; however, the tensile strength did not decrease.     

Eco-friendly dyeing using natural mordant extracted from <Emphasis Type="Italic">Emblica officinalis G</Emphasis>. Fruit on cotton and silk fabrics with antibacterial activity

Emblica officinalis G. dried fruit tannin was extracted and applied as a natural mordant alone and in combination with metal mordant namely copper sulphate for dyeing on cotton and silk fabrics using natural dyes. The color strength, color-coordinates, wash and light fastness were also evaluated for cotton and silk fabrics with and without mordanting. The pre-mordanted cotton and silk fabrics on dyeing gave better color strength, wash and light fastness than those dyeing obtained without mordanting. The total phenolic content of the extract was calculated. Cotton and silk fabrics resulted in good antibacterial activity using the Emblica officinalis G. mordant. When mordant was used along with 0.5 and 1 % copper sulphate mordant and the activity enhanced and was active up to 20 washes.     

Dyeing properties and colour fastness of cotton and silk fabrics dyed with<Emphasis Type="Italic">Cassia tora L.</Emphasis> extract

A natural colorant was extracted fromCassia tora L. using buffer solutions (pH: 2–11) as extractants. The dyeing solution (Cassia tora L. extract) extracted using pH 9 buffer solution was found to give the highest K/S values of dyed fabrics. Cotton and silk fabrics were dyed withCassia tora L. extract at 60°C for 60 min with pre-treatment of various metal salts as mordants. It was found thatCassia tora L. extract was polygenetic dyestuffs and its major components were anthraquinones. Studies have been made on the effects of the kind of mordant on dyeing properties and colour fastnesses of cotton and silk fabrics. The K/S of cotton fabrics increased in the order of the dyeing using FeSO₄>CuSO₄>ZnSO₄>MnSO₄≅Al₂(SO₄)₃>NiSO₄>none, however, the K/S of silk fabrics increased in the order of the dyeing using FeSO₄>CuSO₄>ZnSO₄≅Al₂(SO₄)₃>MnSO₄≅NiSO₄>none. It was found that the K/S values of dyed fabrics were largely affected by the colour difference (ΔE) between mordanted fabric and control fabric. However, they were not depended on the content of mordanted metal ion of the fabrics. Mordants FeSO₄ and CuSO₄ for cotton fabric, FeSO₄, CuSO₄, and Al₂(SO₄)₃ for silk fabric were found to give good light fastness (rating 4).     

Multifunctional modification of wool fabric using graphene/TiO<Subscript>2</Subscript> nanocomposite

In this study, a new finishing technique is introduced through treatment of wool fabric with graphene/TiO₂ nanocomposite. Graphene oxide/titanium dioxide nanocomposite first applied on the wool fabric by hydrolysis of titanium isopropoxide in graphene oxide suspension and then this coating chemically converted by sodium hydrosulfite to graphene/TiO₂ nanocomposite. The homogenous distribution of the graphene/TiO₂ nanocomposite on the fiber surface was confirmed by field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS) and X-ray mapping. X-ray diffraction patterns proved the presence of titanium dioxide nanoparticles with a crystal size of 127 Å on the treated wool fabric. Also, the defect analysis based on X-ray photoelectron spectroscopy (XPS) established the composition of the nanocomposite. Other characteristics of treated fabrics such as antibacterial activity, photo-catalytic self-cleaning, electrical resistivity, ultraviolet (UV) blocking activity and cytotoxicity were also assessed. The treated wool fabrics possess significant antibacterial activity and photo-catalytic self-cleaning property by degradation of methylene blue under sunlight irradiation. Moreover, this process has no negative effect on cytotoxicity of the treated fabric even reduces electrical resistivity and improves UV blocking activity.     

Reducing silk fibrillation through MMA graft method

Silk fibrillation, one major weakness of silk fibers, can lead to undesirable fabric appearance. In this research, an effective method for reducing the fibrillation of silk fibers through the graft copolymerization with methyl methacrylate (MMA) has been developed. The major copolymerization factors such as the initiator concentration, MMA monomer concentration, reaction time and temperature were investigated. An AATCC Crockmeter was used to rub the fabric to simulate the abrasion in production to generate the fibrillation. The microscope observation and the evaluation of fibrillation index (FI) were applied to assess the degree of fibrillation of silk fibers. The optimum graft copolymerization factors were obtained. Instrumental analyses, such as FTIR, TG and SEM, proved that the silk fabric had been successfully grafted with MMA monomers. The fibrillation of the grafted silk fibers was considerably reduced since the coated PMMA can protect the silk fiber. In addition, the physical properties such as the crease recovery, breaking strength, and the breaking length of the grafted silk fabrics were also improved.     

Application of silver nanoparticles to cotton fabric as an antibacterial textile finish

A novel nano-silver colloidal solution was prepared in one step by mixing AgNO₃ aqueous solution and an amino-terminated hyperbranched polymer (HBP-NH₂) aqueous solution under vigorous stirring at room temperature. All results of Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) and UV/Visible Absorption Spectrophotometry indicated that silver nanoparticles had been formed in colloidal solution. Cotton fabric was treated with nano-silver colloid by an impregnation method to provide the cotton fabric with antibacterial properties. The whiteness, silver content, antibacterial activity and washing durability of the silver-treated fabrics were determined. The results indicated that the silver-treated cotton fabric showed 99.01 % bacterial reduction of Staphylococcus aureus and 99.26 % bacterial reduction of Escherichia coli while the silver content on cotton was about 88 mg/kg. The antimicrobial activity of the silver-treated cotton fabric was maintained at over 98.77 % reduction level even after being exposed to 20 consecutive home laundering conditions. In addition, the results of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) confirmed that silver nanoparticles have been fixed and well dispersed on cotton fabrics’ surface and the major state of the silver presented on the surface was Ag⁰.     

Enhancing Stability and Mucoadhesive Properties of Chitosan Nanoparticles by Surface Modification with Sodium Alginate and Polyethylene Glycol for Potential Oral Mucosa Vaccine Delivery

Background: The present study aimed to fabricate surface-modified chitosan nanoparticles with two mucoadhesive polymers (sodium alginate and polyethylene glycol) to optimize their protein encapsulation efficiency, improve their mucoadhesion properties, and increase their stability in biological fluids. Method: Ionotropic gelation was employed to formulate chitosan nanoparticles and surface modification was performed at five different concentrations (0.05, 0.1, 0.2, 0.3, 0.4% w/v) of sodium alginate (ALG) and polyethylene glycol (PEG), with ovalbumin (OVA) used as a model protein antigen. The functional characteristics were examined by dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM)/scanning transmission electron microscopy (STEM). Stability was examined in the presence of simulated gastric and intestinal fluids, while mucoadhesive properties were evaluated by in vitro mucin binding and ex vivo adhesion on pig oral mucosa tissue. The impact of the formulation and dissolution process on the OVA structure was investigated by sodium dodecyl-polyacrylamide gel electrophoresis (SDS-PAGE) and circular dichroism (CD). Results: The nanoparticles showed a uniform spherical morphology with a maximum protein encapsulation efficiency of 81%, size after OVA loading of between 200 and 400 nm and zeta potential from 10 to 29 mV. An in vitro drug release study suggested successful nanoparticle surface modification by ALG and PEG, showing gastric fluid stability (4 h) and a 96 h sustained OVA release in intestinal fluid, with the nanoparticles maintaining their conformational stability (SDS-PAGE and CD analyses) after release in the intestinal fluid. An in vitro mucin binding study indicated a significant increase in mucin binding from 41 to 63% in ALG-modified nanoparticles and a 27–49% increase in PEG-modified nanoparticles. The ex vivo mucoadhesion showed that the powdered particles adhered to the pig oral mucosa. Conclusion: The ALG and PEG surface modification of chitosan nanoparticles improved the particle stability in both simulated gastric and intestinal fluids and improved the mucoadhesive properties, therefore constituting a potential nanocarrier platform for mucosal protein vaccine delivery.     

Improvement of hydrophilicity of polylactic acid (PLA) fabrics by means of a proteolytic enzyme from <Emphasis Type="Italic">Bacillus licheniformis</Emphasis>

Polylactic acid (PLA) has received considerable attention as a biomass material for the textile industry. To use a PLA fabric in the textile industry, suitable postprocessing that can promote hydrophilicity of such fabrics is required. Here, hydrolytic action of a proteolytic enzyme (alcalase from Bacillus licheniformis) on PLA fibers was evaluated. In addition, the effects of an additive on the enzymatic hydrolysis were analyzed. The results revealed that the optimal enzymatic-hydrolysis conditions for this alcalase are pH 9.5, temperature 60 °C, enzyme concentration 50 % on weight of fabric (owf), and Lcysteine concentration of 3 mM. PLA fabrics were hydrolyzed effectively, however; there was no damage to these fabrics judging by tensile strength and surface observations. X-ray diffractometry identified a new peak (at 2θ=18.5 °), implying a morphological change caused by the treatment. Moreover, hydrophilic properties such as moisture regain and dyeing properties were enhanced by this proteolytic enzymatic hydrolysis. Therefore, according to this study, enzymatic hydrolysis is a suitable finishing method for improvement of hydrophilicity of PLA fabrics.     

The enhanced electrical conductivity of cotton fabrics via polymeric nanocomposites

Enhanced electrical conductivity of cotton fabrics coated with polyaniline (PANI) and PANI/carbon coated Fe (Fe@C) and carbon coated Co (Co@C) metal nanoparticles (NPs) composites were investigated. PANI/metal nanoparticle (NP) composites were fabricated with a surface initialized polymerization method and silanization helped with chemical bonding to cotton. The volume resistivity of the samples and structural characterizations were assessed by relevant methods. The results showed that enhanced electrical conductivity, thermal stability and magnetization were obtained via polymeric nanocomposites (PNC) and all these findings revealed that PANI/metal NP PNC coated cotton fabrics would exhibit good level electromagnetic shielding performance as a function of combined electrical conductivity and magnetization which is the objective of our future studies.     

In situ loading TiO<Subscript>2</Subscript> and its photocatalysis and UV resistance on cotton fabric

Anatase TiO₂ nanoparticles was in-situ formed on the cotton fabric by using tetrabutyl titanate (TBT) as a precursor through the normal pressure hydrothermal method. X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV visible spectra (UV-VIS), ATR-IR were used as the characterization techniques. Photocatalytic performance of TiO₂ on the fabric surface was evaluated by methylene blue (MB), 4 kinds of the common living stains and three dyes under ultraviolet and visible light radiation. XRD analysis found that the TiO₂ loaded on the fabric was mainly anatase crystalline phase with particle size of 6.4 nm. SEM observed that a large number of nano TiO₂ particles are distributed on the fabric surface. UV-VIS test indicated that theTiO₂-coated fabric possessed an obvious absorption for ultraviolet. ATR-IR analysis indicated that the nano-TiO₂ possesses a strong affinity with the hydroxyl group of the cotton fabric, and the soaping tests showed that the TiO₂ was firmly bonded with the fabrics. The treated fabrics have good degradation ability for MB aqueous solution, and could degrade azo, anthraquinone and phthalocyanine dyes. The order of degradation of the common life stains was: pepper oil> tea > coffee > soy sauce.