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A novel facile and eco-friendly procedure for fabrication of multifunctional antibacterial and ultraviolet (UV) protective cotton surface was presented, including premodification of cellulose fibres with a polysiloxane matrix, followed by green in situ biosynthesis of silver nanoparticles (Ag NPs) in the presence of sumac leaf extract as a reducing and stabilising agent. During the biosynthesis, face-centred cubic Ag NPs with an average size of 52–105 nm were generated on the cotton fibres. Increasing the concentration of the AgNO3 precursor resulted in increased concentration of Ag NPs of 50–11,000 mg/kg. The chemically modified cotton surface exhibited excellent antimicrobial and UV protection properties. The additive antibacterial activity of Ag NPs and sumac leaf extract showed biocidal activity against S. aureus even at the lowest Ag NP concentration of 50 mg/kg, and in the case of E. coli, biocidal activity was achieved at a concentration of 340 mg/kg. The presence of both Ag NPs and sumac leaf extract provided UV protection factor greater than 40, irrespective of Ag NP concentration. The increase in Ag NP concentration significantly improved the durability of the coating.

The association of an active principle with a nanocarrier is known to improve its stability and protect it from external factors. Nevertheless, loading of nanoparticles with highly hydrophilic substances like caffeine remains a tricky issue. In the present study, inverse miniemulsion systems were successfully coupled to UV radiation to synthesize polymeric nanohydrogels for drug delivery. The proper choice of the continuous and dispersed phase chemical composition led to the entrapment of active principle into the miniemulsion droplets. Our confinement-based strategy enabled unprecedented caffeine encapsulation efficiency inside 100-nm particles. Dimensional, thermal, and spectroscopic characterizations were carried out to investigate both unloaded and loaded nanohydrogels. Furthermore, in vitro release studies evaluated caffeine release kinetics from nanohydrogels by means of dialysis tests. It was demonstrated that controlled and sustained release occurred within the first 50 hours. Experimental data were found to fit the Higuchi model suggesting that the active principle release is diffusion controlled.

Blend films of polyvinyl alcohol (PVA) and keratoses (KOx) were prepared using water as a common solvent. Aqueous solution of KOx from wool was extracted via oxidation using peracetic acid, and different amounts of PVA were added and blended to obtain films by solution casting method. Blend films were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry and tensile measurement. The scanning electron microscopy investigation showed that with decreasing PVA amount, film surface becomes rough and uneven. Thermal behavior and Fourier transform infrared analysis pointed that the two polymers have no covalent interaction each other. Also, it is to be noted that increasing the amount of PVA in the blend from 70 to 100% improved the tensile strength of blend films, and the elongation at break increases dramatically in films containing 70–100% of PVA. Moreover, blends containing 90 and 100% of KOx were too brittle for films production.

In this study, a novel green approach was adopted to develop antimicrobial polyester fabric using sustainable biopolymers (chitosan/derivative) as eco-friendly antimicrobial agents via the resource ...

In this paper, the bifunctional monomer glycidyl methacrylate (GMA) was employed in a simple two-step synthetic strategy with the aim of developing a Nitrazine Yellow-based pH-meter wearable sensor. The catalyzed epoxy ring-opening of GMA allowed the formation of a covalent bond with the sulfonate groups of the halochromic dyestuff, while potassium persulfate thermally initiated the radical grafting of the functionalized NY onto cellulose. Both reactions have been confirmed by Nuclear Magnetic Resonance Spectroscopy and by Infrared Spectroscopy, respectively. Furthermore, the morphology of the treated cotton samples was studied by means of Scanning Electron Microscopy. The pH-halochromic behaviour of the functionalized NY molecule was studied both in solution and onto the fabrics, by means of UV-Vis Spectroscopy, UV-Vis reflectance measurements and CIELAB colour changes. All experimental findings confirmed that the immobilized NY dyestuff still pertains consistent and typical halochromic properties in the pH range 6.0-7.0. The novel functional fabric developed in this work paves the way to non-disposable and reversible wearable pH sensors in smart textiles. Graphic abstract: [Figure not available: see fulltext.]

This study presents a sustainable approach to the fabrication of multifunctional polyester fabric with bioactive natural colourant curcumin through a water free supercritical CO2 dyeing technique. ...

β-Cyclodextrin polymer, namely nanosponges (NSs), were synthesized using two cross-linkers: 1,1′-carbonyldiimidazole (CDI) and pyromellitic dianhydride (PMDA). The synthesized NSs were complexed with N,N-diethyl-meta-toluamide (DEET) and, after complex characterization, the NSs cross-linked with CDI were found more effective than those cross-linked with PMDA in terms of encapsulation efficiency and loading capacity. The CDI-NSs were dispersed in a polyacrylic resin, which was thermally polymerized on a polyester fabric surface. The fabric functionalization was evaluated through quantification of DEET extracted from the polyester fabrics, before and after three washing cycles. The results showed that encapsulation into NSs prolongs the persistence of DEET on polyester fabrics.

The behavior of aqueous chitosan (CH), type-B gelatin (GB) and CH-GB coacervate was studied on oil-in-water emulsion formulation at various pH and concentration ratio. The coacervate was formed by phase separation at ratios CH:GB, 1:10 to 1:1 with total biopolymer concentrations of 0.55%-1.0% (w/v) at pH 4.0-5.5. Soluble complexes were formed below pH 5.0 and coacervate formation was confirmed at pH 5.0 and above by zeta potential and UV-spectroscopy measurements. The coacervate formation was found maximum at the CH-GB ratios of 1:10 and 1:5 at pH 5.5. Formulated emulsions (>10μm droplets) using 1% (w/v) chitosan and GB were found stable (+52.5mv and creaming index 86%) and unstable respectively. Emulsion stabilized by mixed CH:GB 1:5 (3%w/v) had no creaming effect. The instability was attributed to the lower surface activity (K=5.0Lg-1) of pure GB compared to CH (K=14.3Lg-1). The formulation and methods can successfully tune the stability of the emulsions.

Colouration and bio-activation of polyester fabric with curcumin in supercritical CO2: Part I - Investigating colouration properties

In recent years, the textile industry has been moving to novel concepts of products, which could deliver to the user, improved performances. Such smart textiles have been proven to have the potential to integrate within a commodity garment advanced feature and functional properties of different kinds. Among those functionalities, considerable interest has been played in functionalizing commodity garments in order to make them positively interact with the human body and therefore being beneficial to the user health. This kind of functionalization generally exploits biopolymers, a class of materials that possess peculiar properties such as biocompatibility and biodegradability that make them suitable for bio-functional textile production. In the context of biopolymer chitosan has been proved to be an excellent potential candidate for this kind of application given its abundant availability and its chemical properties that it positively interacts with biological tissue. Notwithstanding the high potential of chitosan-based technologies in the textile sectors, several issues limit the large-scale production of such innovative garments. In facts the morphologies of chitosan structures should be optimized in order to make them better exploit the biological activity; moreover a suitable process for the application of chitosan structures to the textile must be designed. The application process should indeed not only allow an effective and durable fixation of chitosan to textile but also comply with environmental rules concerning pollution emission and utilization of harmful substances.

The textile industry has recently been developing innovative products that integrate functional properties within commodity textiles. In particular, research has focussed on the concept of biofunctional textiles, i.e., textile materials possessing beneficial properties for human health. Biofunctional textiles are synthesised by functionalization of fabric surfaces with biopolymers. As an example, the chitosan biopolymer is promising for textile functionalization due to chitosan availability, low cost, safety and unique properties. Yet several challenges have to be overcome. Firstly, the morphology of chitosan must be optimized prior chitosan application to the textile surface. Secondly, the last treatment must be carefully designed in order to achieve an effective and durable functionalization. Lastly, the overall production process must comply with environmental rules concerning pollution emission and utilization of harmful substances. This review describes microencapsulation as a strategy to overcome limitations and to confer better properties to the textile material. The properties of chitosan and the concept of microencapsulation are presented. Then we present the main techniques of chitosan encapsulation. Furthermore, we detail the textile finishing processes and the textile products. Last, the perspectives are discussed in the context of green chemistry and compliance with an environmentally friendly approach.

Flash nanoprecipitation (FNP) is a widely used technique to prepare particulate carriers based on various polymers, and it was proven to be a promising technology for the industrial production of drug loaded nanoparticles. However, up to now, only its application to hydrophobic compounds has been deeply studied and the encapsulation of some strongly hydrophilic compounds, such as caffeine, remains a challenge. Caffeine loaded poly-&epsilon, caprolactone (PCL) nanoparticles were produced in a confined impinging jet mixer using acetone as the solvent and water as the antisolvent. Caffeine was dissolved either in acetone or in water to assess the effects of two different process conditions. Nanoparticles properties were assessed in terms of loading capacity (LC%), encapsulation efficiency (EE%), and in vitro release kinetics. Samples were further characterized by dynamic light scattering, scanning electron microscopy, X-ray photo electron spectroscopy, and infrared spectroscopy to determine the size, morphology, and structure of nanoparticles. FNP was proved an effective technique for entrapping caffeine in PCL and to control its release behavior. The solvent used to solubilize caffeine influences the final structure of the obtained particles. It was observed that the active principle was preferentially adsorbed at the surface when using acetone, while with water, it was embedded in the matrix structure. The present research highlights the possibility of extending the range of applications of FNP to hydrophilic molecules.

A series of chitosan/gelatin based microcapsules containing n-hexadecane was synthesized through complex phase coacervation from chitosan (CH) and type-B gelatin (GB), and crosslinked by glutaraldehyde (GTA). This research was conducted to clarify the influence of different parameters on the encapsulation process, i.e., the emulsion formation and the shell formation, using zeta potential and surface tension measurements, attenuated total reflectance (ATR), and thermal analysis such as differential scanning calorimetry (DSC). The optimal values of biopolymer ratios (TBP), crosslinker amount, emulsion time and feeding weight ratio of core/shell polymer (RCS) were identified. The stability of the emulsion was depended on the surface activity and TBP ratio, which also affected the droplet size distribution and the thickness of the shell. Furthermore, core content, encapsulation efficiency and thermal properties of the microcapsules were related to TBP and RCS; with the lowest RCS giving the best microcapsules features.

In recent years transdermal drug delivery has aroused significant interest as a sustained and non-invasive way of administering active substances. The advancements of nanotechnology allowed the development of novel pharmaceutical formulations overcoming skin barrier. Furthermore, such nano-system can be combined with conventional fabrics to pave the way to a new generation of wearable drug delivery devices: bio-functional garments. First the NP were produced by flash nanoprecipitation technique (FNP), the production process was optimized to produce particles with suitable size for transdermal applications. The nanoparticles were characterized in terms of drug content by UV-visible spectroscopy and in term of antioxidant activity by Electron Paramagnetic Resonance spectroscopy (EPR) coupled with spin trapping technique. The NPs were used to functionalize cotton and viscose-micromodal fabrics and the transdermal release properties were tested in vitro by Franz's Cell experiment. FNP was proven to be an effective technique to produce tunable size particles. Moreover, the nanoencapsulated drug exhibited antioxidant activity. The Franz's Cell test evidenced a controlled release behavior, providing evidence that the bio-functional textile is suitable for applications where sustained release and antioxidant properties are required.

Cotton functionalisation with poly-"-caprolactone (PCL) micro- and nano-capsules containing menthol was carried out with the aim of introducing a long-lasting refreshing sensation.Materials and methods: The preparation of the polymer micro- and nano-capsules was carried out by solvent displacement technique. A confined impinging jets mixer was used in order to ensure fast mixing and generate a homogeneous environment where PCL and menthol can self-assemble.Results: The micro- and nano-capsules and the functionalised fabrics were characterised by means of DSC, FT-IR spectroscopy and SEM imaging. Micro- and nano-capsules of different size, from about 200 to about 1200nm, were obtained varying menthol to PCL ratio (from 0.76 to 8), overall concentration and flow rate (i.e. mixing conditions). The inclusion of menthol was confirmed by DSC analysis. Discussion and conclusion: A patch test was carried out by 10 volunteers. Micro-capsules were found to be effective in conferring the fabric a refreshing sensation without altering skin physiology. less

Drug delivery by means of transdermal patches raised great interest as a non-invasive and sustained therapy. The present research aimed to design a patch for transdermal delivery of melatonin, which was encapsulated in polycaprolactone (PCL) nanoparticles (NPs) by employing flash nanoprecipitation (FNP) technique. Melatonin-loaded PCL nanoparticles were successfully prepared with precise control of the particle size by effectively tuning process parameters. The effect of process parameters on the particle size was assessed by dynamic light scattering for producing particles with suitable size for transdermal applications. Quantification of encapsulated melatonin was performed by mean of UV spectrophotometry, obtaining the estimation of encapsulation efficiency (EE%) and loading capacity (LC%). An EE% higher than 80% was obtained. Differential scanning calorimetry (DSC) analysis of NPs was performed to confirm effective encapsulation in the solid phase. Cotton fabrics, functionalized by imbibition with the nano-suspension, were analyzed by scanning electron microscopy to check morphology, adhesion and distribution of the NPs on the surface; melatonin transdermal release from the functionalized fabric was performed via Franz’s cells by using a synthetic membrane. NPs were uniformly distributed on cotton fibres, as confirmed by SEM observations; the release test showed a continuous and controlled release whose kinetics were satisfactorily described by Baker–Lonsdale model.

This chapter reviews relevant findings regarding the activities and contributions of chitosan in different textile processing following the varieties of process, mechanism, and applications. Chitosan is a better candidate in both aspects of biodegradability and efficiency instead of synthetic polymers. The technical and scientific discussions behind the role of chitosan in all the processes and treatments have been explored in the chapter. Over the last few years, enormous efforts and challenges are being practiced in research and industry to design and development of eco-friendly and sustainable technologies. Therefore, the chapter emphasizes on chitosan-based formulations of fibers, fabrics, coatings, and functional textiles.

Waste of fruits in their supply chain is an issue that is drawing increasing interest. Postharvest ripening processes enable better control of the ripening and diminish the loss of produce. Many of these techniques consist of exposure of fruits to controlled concentrations of ethylene, which acts as a phytohormone and trigger the ripening process. In this work, a new way to control the ethylene administration is studied. Inclusion complexes of ethylene in α-cyclodextrin are produced by molecular encapsulation and the crystals obtained are dispersed in thermosetting films made of Poly(ethylene glycol)diacrylate polymerized by UV-curing. The samples are then characterized with respect to thermal behavior, complex crystalline structure and ethylene release kinetics both from the loose crystals and those embedded into the polymeric films.

In modern fruit supply chain a common method to trigger ripening is to keep fruits inside special chambers and initiate the ripening process through administration of ethylene. Ethylene is usually administered through cylinders with inadequate control of its final concentration in the chamber. The aim of this study is the development of intelligent polymeric supports able to accurately regulate ethylene concentration in the atmosphere where fruits are preserved. Two different technologies were proposed: a polymeric (PEGDA) film and a polymeric (PLA) bag filled with inclusion complex of ethylene/α-cyclodextrin. The complex was prepared by molecular encapsulation which allows the entrapment of ethylene into the cavity of α-cyclodextrin. After encapsulation, ethylene can be gradually released from the inclusion complex and its release rate can be regulated by temperature and humidity. Intelligent polymeric film was prepared by dispersing inclusion complex into a thin polymeric film produced by UV-curing. Intelligent polymeric bag was made by inserting inclusion complex into heat sealed bag. The kinetics of ethylene release was studied for both systems, showing that it can effectively possible to control the release of ethylene within confined volume. Furthermore, modelling and simulations of ethylene release in a food container were made, demonstrating that it is possible to modulate release rate and, thus, control ripening.

The aim of the work was to investigate the effect of an ethanol addition in the dyeing of a commercial polyethylene terephthalate yarn with supercritical carbon dioxide. The equilibrium uptake in the yarn and the partition coefficients of three azo dyes between the polymer and the fluid phases were experimentally measured under different working conditions and compared with the data obtained without any modifier. It was found that the presence of the modifier increases the dye concentration in the yarn and the solubility of the dye in the supercritical phase, allowing good dyeing results to be obtained under less severe working conditions. The partition coefficient data were also satisfactorily regressed with a semi-empirical correlation, available in the literature for a different system and here adapted to the partition of a dye between a fibre and a supercritical bath.

In modern fruit supply chain a common method to trigger ripening is to keep fruits inside special chambers and initiate the ripening process through administration of ethylene. Ethylene is usually administered through cylinders with inadequate control of its final concentration in the chamber. The aim of this study is the development of a new technology to accurately regulate ethylene concentration in the atmosphere where fruits are preserved: a polymeric film, containing an inclusion complex of α-cyclodextrin with ethylene, was developed. The complex was prepared by molecular encapsulation which allows the entrapment of ethylene into the cavity of α-cyclodextrin. After encapsulation, ethylene can be gradually released from the inclusion complex and its release rate can be regulated by temperature and humidity. The inclusion complex was dispersed into a thin polymeric film produced by UV-curing. This method was used because is solvent-free and involves low operating temperature; both conditions are necessary to prevent rapid release of ethylene from the film. The polymeric films were characterized with respect to thermal behaviour, crystalline structure and kinetics of ethylene release, showing that can effectively control the release of ethylene within confined volume.

The aim of this work is the investigation of the solubility of three disperse dyes in a mixture of CO2 and ethanol. Experimental solubilities of disperse blue 79, disperse orange 3 and solvent brown 1 in a mixture containing 5.5 mol% of ethanol in carbon dioxide have been measured using a dynamic apparatus and compared with those in pure carbon dioxide [A. Ferri, M. Banchero, L. Manna, S. Sicardi, J. Supercrit. Fluids 30 (2004) 41–49]. The effect of the co-solvent is so pronounced that solubilities similar to those measured in pure carbon dioxide have been achieved in the mixture at pressures 100 bar lower. The experimental results have been correlated with three different approaches: the Peng–Robinson equation of state [D.Y. Peng, D.B. Robinson, Ind. Eng. Chem. Fundam. 15 (1976) 59–63], the semi-empirical Chrastil equation modified for ternary systems [J.C. Gonzales, M.R. Vieytes, A.M. Botana, J.M. Vieites, L.M. Botana, J. Chromatogr. A 910 (2001) 119–125] and, finally, a correlation recently proposed by our research group for binary systems [A. Ferri, M. Banchero, L. Manna, S. Sicardi, J. Supercrit. Fluids 32 (2004) 27–35] here applied for the first time to ternary systems. The results have pointed out that the third semi-empirical equation gives the best agreement between the experimental and calculated solubilities.

Supercritical dyeing has risen good expectation in the last few years due to the attractive perspective of complete elimination of water from dyeing processes. A lot of research activities have been developed in the last decade both to deepen the knowledge of the interaction mechanisms between CO 2 , dye and polymers and to solve the technological problems of the process set-up. Among the last ones that of a non-uniform dye distribution when a yarn package is subjected to dye impregnation is one of the most undesired. The same problem is usually faced in the industrial practice of traditional aqueous dyeing and has always been solved empirically. Aim of the present work is to propose a simple model that simulates the dyeing process of a spool of yarn both with the aqueous and supercritical techniques pointing out the main characteristic times and allowing calculation of dye concentration profiles both in the dyeing ‘bath’ and along the yarn spool. The analysis of the influence of characteristic times ratios gives some indications on the best operative conditions that should be attained to guarantee an uniform dye distribution along the package radius both for aqueous and supercritical dyeing; the two processes, in fact, mainly differ for the order of magnitude of the characteristic times. To support the discussion arisen from the different roles of characteristic times on the model, a practical example of supercritical dyeing simulation is also performed for a specific PET package with a disperse dye already used in the literature at well defined working conditions.

Unsteady-state operation of trickle-bed reactors (TBRs) is a promising technique to improve reactor performances especially when mass transfer phenomena are rate controlling. Among the different techniques, fast-mode modulation of the liquid flow rate seems to be one of the most successful. In fact cycling the liquid flow rate at very low frequencies can induce the reactor to work at the high-interaction regime where mass and heat transfer phenomena are strongly enhanced. Fast-mode periodic operation, then, can be considered an extension of the natural high-interaction regime at a mean range of gas and liquid flow rate normally associated with trickling regime in steady-state conditions. Experimental tests have been performed in a TBR employing α-methyl styrene hydrogenation on Pd/C catalyst in unsteady-state conditions by “on–off” fast-mode liquid modulation. Results have been compared with the steady-state experiments at the corresponding average liquid flow rate, revealing a conversion rate improvement up to 60%. All experiments have been performed in isothermal conditions, so conversion improvement can be ascribed only to mass transfer increase and not to thermal effects. The variation of gas and liquid flow rates and liquid cycle parameters presented several important implications about the optimal working conditions.

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.

a b s t r a c t The cotton used to produce an interlock knitted fabric is alkaline boiled, bleached and after drying, it is grafted with monochlorotriazinyl-beta-cyclodextrin (MCT--CD) as a support of an inclusion com- pound (IC) with natural anti-allergic active principles, in order to improve the curative properties and the comfort. Are used: extract of Viola tricolor Herb (VtH), solution of propolis (P) and of menthol (M), as well as the pharmacologic products: advantan (AD), hydrocortisone (HYD) and pimechrolimus (PI). The dimensions of the active compound molecules were established with software. The textile material grafted with MCT--CD and with active principles absorbed in the cyclodextrin cavity is investigated by EDX. The anti-microbial activity of VtH, P and M was tested. Tactile determinations of softness were performed with human appraisers. By assembling the anti-allergic knitted fabric with untreated fabric, therapeutic pajamas were obtained. The manner to process and manufacture the pajamas for patients with contact and atopic (DA) dermatitis (DC) is presented.

Cotton yarns bobbins were treated in a water bath with different concentrations of a reactive β-cyclodextrin derivative. To quantify the amount of cyclodextrin fixed on the fiber different analytical methods were tested but none of them was reliable enough in the concentration range under investigation. Therefore, a new analytical method, fast and effective, was developed. From the measurement of cyclodextrin bath exhaustion, the amount of cyclodextrin chemically fixed and that physically adsorbed on the textile substrate was estimated. Two washing cycles were carried out to investigate the cyclodextrin washing fastness.

Carbon dioxide (CO2) is becoming a promising alternative to perchloroethylene in dry cleaning. In this work, the effect of CO2 dry cleaning on some physical and mechanical properties of six different pure wool and wool/cashmere fabrics was investigated in order to detect any possible fabric modification. It was found that the CO2 dry cleaning process especially affected the thickness and compressional energy, making the fabrics thicker and fuller. A marked increase in shear hysteresis was detected, while no particular variations in bending and tensile properties or crease pressing performance were noted. Finally, there was a significant decrease in the air permeability of three of the six fabrics involved.

The solubilities of colour index (C.I.) disperse orange 3, red 324, blue 79 and quinizarin were measured at the temperatures of 353.2, 373.2, 393.2 K between 18 and 30 MPa with a ‘flow method’ conceived for determination of high solubilities in order to avoid the flow instability problems connected with dye precipitation. The comparison of results with the literature underlines the advantage of this new technique: higher solubility values are obtained especially at the most severe operating conditions. Experimental data for disperse orange 3 were also compared with similar results obtained by the authors using a ‘batch method’ in a previous work. The comparison of the results shows how the ‘flow method’, even though adapted for high solubility measurements, reveals to be the simplest and more efficient technique to evaluate dye solubility in supercritical fluids.