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Chitosan is a biopolymer with unequalled properties such as biodegradability, nontoxicity, and antimicrobial activity. It is a carbohydrate polymer derived from the deacetylation of the chitin component of the shells of crustacean; hence, it is a renewable material widely available as a byproduct of the food industry. Owing to its extremely interesting properties, chitosan has been extensively applied to textile fibers to confer various functional properties such as • antimicrobial activity with a green chemistry approach for aesthetic, hygienic, and medical applications; • antifelting properties for wool fabrics; • increasing uptake of ionic dyes in dyeing processes; • removal of dyes and other organic pollutants from wastewaters; • removal of heavy metal ions from contaminated wastewaters. A fundamental problem that arises in order to obtain durable chitosan coatings on textiles is due to the low wash fastness of the biopolymer; hence, thermal treatments or cross-linking agents are needed to obtain strong bonding with the fibers. Wet thermal curing involves energy consumption and possible fiber degradation, whereas the most of cross-linking agents such as dialdehydes are toxic. Therefore, many research works were aimed to investigate safer grafting methods with physical means such as UV irradiation or with green chemicals.

The topic of the present study was the antibacterial finishing of cotton fabrics by ultraviolet grafting of chitosan biopolymer on fiber surface. A first part, carried out at laboratory level, deals with the optimization of process parameters, followed by a deep characterization of treated samples, revealing the effectiveness of the treatment. Therefore, the applied method was carefully monitored, laboratory apparatus were used and just samples of small surface were prepared by UV-grafting of pure chitosan in inert atmosphere, on dried samples, as recommended for radical curing. To test the feasibility of the proposed treatment even at semi-industrial level, in the second step of the study larger fabric samples were impregnated by foulard with a commercial chitosan solution and then were irradiated, both dried and wet, with an high power UV lamp, in air. Moreover, samples add-on was significantly reduced in order to hold down the finishing cost. White and dyed samples were treated and evaluated in terms of conferred antibacterial activity, yellowing or color changes and final hand. Eventually, treatment fastness to domestic laundering was tested. Obtained results confirmed the previous laboratory results: a strong antibacterial activity with good washing fastness was achieved by irradiation of the samples even wet and in air. It was obtained with a chitosan add-on percentage lowered till 0.3 wt% with a negligible affection of color or hand properties of the fabric.

The substances responsible for the yellowing of wool treated with nitric acid are two amino acid constituents of the fibre: tryptophan and tyrosine. Nitric acid penetrates the fibres and carries out electrophilic aromatic substitution on the two above-mentioned amino acid residues, producing different colour yields. The intensity of yellowing depends in various ways on the treatment conditions (time, temperature, nitric acid concentration, agitation, and liquor ratio). Yellowing evaluation shows abnormal yellowing depending on acid concentration in the range 5.6-5.9 M. Working in this region makes it possible to use the chromatic reaction in order to show the damage done to wool fibres by the oxidising agents utilised in normal antifelting treatments. Wool damage by the oxidants is usually evaluated by dyeing methods based on different affinity of damaged fibres. By contrast, the xanthoproteic reaction yields chromogens as a function of the accessibility of tryptophan and tyrosine residues for the action of nitric acid on damaged fibres, and can be used for assessing the degree of antifelting treatment and its possible unevenness through the development on the treated wool of a yellow coloration more intense than on untreated wool.

A chitosan-coated cotton gauze was prepared by UV-curing and tested as adsorbent to remove copper (II) and chromium (VI) ions from water solutions. The adsorbent characterization was carried out by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transform Infrared Spectroscopy in Attenuated Total Reflection (FTIR-ATR). Adsorption of copper and chromium ions onto the gauze was tested in batch process at different experimental conditions. The effects of pH, temperature, contact time and metal ion concentration were investigated. The optimum adsorption took place at pH 3 for Cr(VI) and pH 5 for Cu(II) ions respectively, while the temperature did not affect the adsorption process. Pseudo-first and pseudo-second order models were used to investigate the adsorption kinetics which was found very fast and better described by the pseudo-second order model for both metal ions. The adsorption of Cr(VI) ions was satisfactory described by the Langmuir isotherm, while that of Cu(II) ions showed a better agreement with the Freundlich model. © 2014 Elsevier Ltd.

Communicable diseases can be transmitted by contaminated water. Water decontamination process is fundamental to eliminate microorganisms. In this work, cotton gauzes were coated with chitosan using an UV-curing process or cationized by introduction of quaternary ammonium groups and tested, in static and dynamic conditions, as water filter for biological disinfection against both Gram-negative and Gram-positive bacteria. Both materials showed good antibacterial activity, in static assessment, instead in dynamic conditions, chitosan treated gauze showed a high antimicrobial efficiency in few seconds of contact time. This composite could be a good candidate for application as biological filter. © 2013 Elsevier Ltd.

The use of antimicrobial compounds in textiles has grown dramatically over the last decades. The potential application field is wide. It ranges from industrial textiles exposed to weather such as awnings, screens and tents; upholstery used in large public areas such as hospitals, hotels and stations; fabrics for transports; protective clothing and personal protective equipment; bed sheets and blankets; textiles left wet between processing steps; intimate apparel, underwear, socks and sportswear. Another large field of application is in filtration and disinfection of air and water for white rooms, hospitals and operating theatres, food and pharmaceutical industries, water depuration, drinkable water supplying and air-conditioning systems. The present chapter is a review of recent research works related to antimicrobial finishes for textile materials. Several examples of antimicrobial treatments (e.g. traditional pad-dry-cure technique, exhaustion bath, encapsulation, electrospinning, cross-linking, etc.) were reported. The antimicrobial agents were divided by their origin from synthesis or from natural sources. Quaternary ammonium compounds (QACs), Triclosan, metals (including metal oxides and salts), polyhexamethylene biguanide (PHMB), N-halamines and conjugated polymers (i.e. polypyrrole) were listed as synthetic biocides in textile applications. Extracts from plants (e.g. aromatic compounds, essential oils and dyes), antimicrobial peptides (AMPs) and chitosan were considered among natural-based biocides.

In this work, various textile fabrics were coated with silicone and fluorocarbon-based resins by photo-curing using ultraviolet irradiation. A great number of large fabric samples were impregnated by padding with commercial finishing agents and then irradiated in air with a high power, semi-industrial UV source. The add-on of various finishing agents was kept low to reduce the treatment cost. White and dyed samples of different textile composition were treated and evaluated in terms of conferred repellency, yellowing, or color changes. Most relevant process parameters were investigated, utilizing the thermal process normally adopted at industrial level as reference. The results were statistically evaluated by ANOVA using Minitab 16 software, in order to identify the most influential parameters and to evaluate the real possibility of replacing the thermal treatment with UV curing.

Ultraviolet (UV) radiations can act in different ways on the functionalization of textiles, through pre- or posttreatments, in order to modify their behavior in dyeing and finishing processes. In cotton fiber, unlike the wool, the UV absorption is not due to any of the structural groups of the normal cellulosic chains and can only be attributed to "impurities" or "faults" bearing carbonyl and/or carboxyl groups. In fact, UV irradiation coupled with mild oxidation can improve some properties of the cotton fibers such as pilling resistance, water swelling, and dyeability. Therefore, the process of differential dyeing with direct and reactive dyes assisted by UV irradiation was studied and interesting differential chromatic effects were obtained by a UV post-treatment capable to fade dyeing. On the other hand, the surface modification of cotton fabrics by UV curing and UV grafting with suitable chemicals was pursued to obtain finishing treatments able to confer oil and/or water repellency. Finally, antimicrobial finishing by chitosan UV grafting was proposed as valid environmental friendly method to confer a satisfactory washing-resistant antimicrobial activity to cotton fabrics even with low polymer add-on

The purpose of this research work was to develop a textile finish based on the radical UV-curing of chitosan on textiles to confer antimicrobial properties. Chitosan is a biopolymer with unique properties such as biodegradability, non-toxicity, antimicrobial activity. In this work cotton or silk fabrics and synthetic filter fabrics were impregnated with an acid solution of chitosan added of the photoinitiator in the proper amount and cured at room temperature by exposure to UV lamp. Process conditions such as percentage add-on, dilution, chitosan-fabric contact time, irradiation time and power, were optimized. The antimicrobial activity of finished fabrics was tested according to ASTM E 2149-01 standard test performed with Escherichia Coli ATCC 8739. Moreover dyeing test with Turquoise Telon dye were carried out to evaluate the treatment homogeneity while the amino group content was determined by ninhydrin assay. Moreover on cotton and silk fabrics the treatment fastness to domestic laundering was tested, according to UNI EN ISO105-C01. Obtained results showed a strong antimicrobial activity conferred by the treatment, homogeneous on fabric surface. It is evident already at low add-on, without affecting the hand properties of natural fabrics and the filtration characteristics of the synthetic filter fabrics. Finally, washing fastness was better for samples prepared with a better penetration of chitosan inside the fibers.

In this study, cotton, polyester and polyamide fabrics were treated by radical or cationic ultraviolet curing of different commercial products conferring water and oil repellency. Moreover, radical ultraviolet curing of chitosan was applied to confer antimicrobial properties. The advantages of this technology are well known making it very interesting for industrial applications: energy savings, low environmental impact, simple, cheap and small equipment, high treatment speed. The polymerization was controlled through weight gain and gel content measurements, while the properties of hydro and oil repellency were determined in terms of contact angle, moisture adsorption and water vapor permeability. The polymer distribution on fabric surfaces was investigated by scanning electron microscopy and atomic force microscopy. However the fabrics treated with chitosan were subjected to the standard test for determining the antimicrobial activity. Finally the finished cotton samples were subjected to washing fastness tests.

Dyeing processes of various yarns (wool, cotton, polyester, nylon 6 and acrylic) were studied with the aim to substitute some auxiliary agents with ethanol at low concentration. The results observed in isothermal dyeing showed a favorable effect of alcohol addition, at about 1–3% v/v, on the dye uptake, with some differences depending on fiber nature and dye class. This effect was correlated with contact angle measurements of water-ethanol solutions on the mentioned yarns, which confirmed a lower surface tension in the same concentration range. Then, laboratory tests with dye triads at programmed temperature were carried out comparing the results of standard dyeing recipes with those obtained by replacing wetting, retardant and leveling agents with ethanol. Good color imitations were generally shown with respect to standard processes. A wetting effect of ethanol was shown for all the tested yarns and dye classes, while in wool dyeing with acid, pre-metallized and reactive dyes, ethanol was suitable to replace also leveling and retarding agents. Light and wash fastnesses were also compared. Finally the environmental benefits arising from chemical substitution of auxiliary agents with ethanol were highlighted and the cost of alcohol introduction was compared with the cost saving of auxiliary substitution. A positive economic balance was obtained.

The application of enzymes in the wool dyeing process is an important research goal in order to reduce the environmental impact and costs of this finishing process. The work has focused on the possibility of reducing the temperature of conventional dyeing, using an enzymatic pretreatment with a neutral protease to improve the diffusion of the dye into the fibers. After the identification of the optimal dyeing process, the study goes on transferring the method to an industrial application. For this reason the influence of a leveling agent added to the dyeing bath was considered and further tests with an industrial dyeing recipe were performed. In order to evaluate possible fiber damage, samples treated with enzyme were observed by scanning electron microscopy (SEM) and analyzed by gel electrophoresis (SDS-PAGE). Moreover, the variation of tensile strength and elongation of dyed samples were determined. In addition, color fastness to domestic laundering, perspiration and rubbing were carried out. Finally, color measurements and fiber section analysis were performed. The results show the possibility, thanks to the pretreatment with the investigated enzyme, to obtain a homogeneous and solid dyeing on fibers maintaining good mechanical properties, already working at 85°C instead of 98°C currently used in industry.

Conventional wool dyeing methods are based on long times at high temperatures. These are energy intensive and can even damage the fibers, thus changing the desired fiber characteristics. In this work, enzyme pretreatment in combination with lower temperatures was used to reach exhaustion values comparable to those obtained with the standard procedure at 98 degrees C. Kinetic runs carried out on wool yarn at different temperatures confirmed the possibility of obtaining more than 90% of bath exhaustion by dyeing at 85 degrees C due to the pretreatment with a proteolytic enzyme. At the same temperature, without enzymatic pretreatment, just 77% of bath exhaustion can be reached. The enzyme action on the dyeing kinetics was investigated through calculation of dye absorption rate constants according to the diffusion-limited kinetic model proposed by Chrastil. Dynamometric measurements on the yarn dyed at 98 degrees C showed a 25% loss of tensile strength and 50% loss of elongation, while at lower temperature the values were better even after enzyme pretreatment, in agreement with the results of scanning electron microscopy analysis. A temperature of 85 degrees C with enzyme pretreatment was found to be optimal taking into account satisfactory washing, perspiration and light fastness values.

An atmospheric pressure plasma jet (APPJ) for continuous treatment of polymeric films and textile materials was investigated to characterize its thermal, hydrodynamic and chemical features. The operative variables of the plasma jet equipment are: gas flow rate and composition, electrical power to the plasma generator and fabric velocity. A diagnostic evaluation of the equipment was carried out to improve the treatment homogeneity and generate an effective feedback for scale-up. The cross profile of gas temperature and velocity, the fabric temperature and concentration transitory in the gas system generated by a reverse step of oxygen were determined. These measurements showed that the original prototype configuration required a better gas distribution to fully demonstrate its potentiality to functionalize textiles. The surface modifications induced by plasma were detected by processing wool fabrics and by evaluating the treatment benefit on dyeing.

Keratin proteins are the major component of hair, feathers, wool and horns and represent an important source of renewable raw materials for many applications. Regenerated keratin has useful properties such as biocompatibility and biodegradability. Moreover, keratin materials can absorb heavy metal ions, formaldehyde and other VOCs. In this work, regenerated keratin was blended with aqueous solutions of poly(ethylene oxide) (PEO) in different proportion in order to improve its processability. Keratin/PEO nanofibres were produced by electrospinning the blend aqueous solutions. The chemical, physical and rheological characteristics of the blend solutions were correlated with morphology, structural, thermal and mechanical properties of the electrospun mats.

Total organic carbon (TOC) removal from Methylene Blue aqueous solutions in the presence of coal fly ash was experimented comparing adsorption alone with oxidation potentially catalyzed by ash carried out with oxygen or ozone-enriched oxygen flow. The experiments were performed in continuous stirred tank reactor with fixed amounts of ash and dye solution, while gaseous flow was continuously bubbled in the solution. The results of TOC removal from 20 mg/L Methylene Blue aqueous solution showed that in the case of adsorption alone the removal yield rose from 62 to 90% increasing ash dosage from 4.0 to 8.0 g/L. However, in oxygen flow only the removal with 4.0 g/L increased up to 72% and attained about 80% with ozone-enriched oxygen, yielding the best final values of TOC removed per unit mass of ash of 2.19 and 2.38 mg/g, respectively. The kinetic results have been satisfactorily fitted by a pseudo-second-order model yielding a kinetic constant which strongly increased in adsorption alone increasing ...

Anti-felting properties of knitted wool fabrics treated with chitosan were investigated, by both a laboratory scale treatment and a semi-industrial application. The influence of oxidative wool pre-treatments was analysed. The distribution of chitosan on treated wool fibres was also assessed using both qualitative and quantitative evaluation methods. The study provided shrinkage data perfectly comparable with those obtained by the currently used shrinkproofing processes, but with two important advantages: the total absence of chlorine in the process and the complete biodegradability of chitosan. The semi-industrial treatment showed the complete reproducibility of the laboratory scale results, giving rise to the possibility of an industrial adaptation of the process.

Cotton fabrics were water-repellent-finished by radical ultraviolet curing of silicone and urethane acrylates with different formulations. The fabrics were impregnated with undiluted resins and with toluene solutions or water emulsions. Moreover, cationic ultraviolet-curable systems were also investigated, such as an epoxy-functional polysiloxane and mixtures of an epoxy resin with hydroxyl-containing silicone additives. The gel content and polymerization yield were considered for the ultraviolet-curing process evaluation. Water-resistance properties were determined in terms of the contact angle, wettability, moisture adsorption, and water vapor permeability measurements, whereas the morphology and surface composition of treated fabrics were examined with scanning electron microscopy and energy-dispersive X-ray analysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Coating the fibre surface by in situ oxidative chemical polymerisation of polypyrrole (using FeCl(3) as oxidant) is a readily industrial applicable way to give electrical properties to wool with good ageing stability [1], although pre-treatments are required to avoid damage of the cuticle surface due to the acidic condition of the process. FT-IR and EDX analysis reveal that organic sulphonates and sulphates, used as dopants, are absorbed by wool, while chlorine ions are preferably embedded on the polypyrrole layer. The resulting electrical conductivity seems mainly due to the presence of chlorine as counter-ion of polypyrrole; nevertheless, the presence of arylsulphonate in the polymerisation bath increases the electrical conductivity of the coating layer.

Air plasma treatment at low pressure was applied to modify the surface of a cellulose film with the aim to improve its wettability, dyeability and adhesion properties. The contact angles of different polar liquids on the treated films show an exponential decay with treatment time at a given power; the power–time reciprocity is followed. The calculated surface tension values exponentially rise to the same maximum value with a decrease of the polar fraction. ATR-FTIR analyses suggest that a cellulose dehydration takes place rather than a surface oxidation. The plasma treatment improves also the cellophane dyeability with typical dyes for cellulose fibers: the results of dye uptake follow the same trend as the surface energy. The bond strength of lap joints of cellophane with LLDPE film shows a strong improvement of the adhesion depending on the duration and the power of treatment. The whole results are consistent with ablation effects like those observed with air corona treatment rather than oxygen plasma.

The chemical polymerization of pyrrole was studied with the aim of defining the best operating conditions for obtaining conductive fabrics of synthetic fibers. Ammonium persulfate was chosen as the oxidant, and various dopants were tested. Among these, naphtalene-2,6-disulfonic acid disodium salt enabled the lowest surface resistivity to be reached. Hence, several kinetic runs were performed to explain the influence of some operating conditions as oxidant concentration and temperature. A pseudo-first-order kinetic equation was derived, and the reaction rates were found to be practically unaffected by the presence of the textile substrate. Pyrrole polymerization was faster than adsorption of the monomer, suggesting the hypothesis of fast polymerization outside the fibers followed by adsorption onto the fiber surface. The surface coating of polypyrrole was evidenced by microscopic observation of the fiber cross sections. ©2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4121–4126, 2006

The process of silk weighting with methacrylamide (MAA) initiated by ammonium persulfate was studied to optimize the operating conditions to obtain high yields of grafted monomer. The influence of MAA concentration, liquor ratio, concentration of initiator, contact and heating time, acidification, and swelling agents were considered, and optimum operating conditions were outlined. Moreover, various monomethacrylates and dimethacrylates were grafted onto silk as alternative to methacrylamide. Most of these showed graft yields higher than MAA in the same operating conditions and some were found suitable for silk weighting since the weighted fibers show soft hand and good dyeing behavior. DSC and TGA analyses of grafted silk enabled to evaluate the influence of various monomers on the thermal behavior of the weighted fibers. Moreover, on the basis of DSC data, a correlation between the calculated enthalpy of grafted polyMAA and monomer content was studied. The molecular structure of silk grafted with methacrylic monomers was finally characterized by FTIR analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4039–4046, 2007

The acrylation of polybutadienes was performed by reaction of acrylic acid with epoxy, epoxy-hydroxyl functionalized and hydroxyl-terminated oligomers. Some epoxy-functionalized oligomers were previously obtained by epoxidation of a liquid 1,4-polybutadiene. The properties of the acrylated products were affected by the oligomer type and the reaction procedure. The UV-curing of these products was studied by FTIR and thermal analyses, which showed the amorphous and rubbery nature of the resulting films. In some cases, the double bonds conversion was increased by a thermal post-curing, but the adhesion properties were strongly reduced. The swelling of the UV-cured films was studied by varying the solvent polarity. The mixtures of some polybutadiene-acrylates with a typical epoxy-acrylic resin gave highly cross-linked films showing a flexibilizing effect due to the polybutadiene oligomers which can act as reactive diluents.

The maleinization of liquid polybutadienes with different microstructures was studied in two solvents: o-xylene and decahydronaphtalene. The concentration of maleic anhydride versus time was determined by gas chromatographic analysis. The results obtained in o-xylene were processed according to a first-order model, hence the kinetic constants and estimated activation energy values showed a solvent effect with respect to the bulk reaction. Moreover, the model was improved by taking into account that at 140 °C, the kinetic curves reached after some time a final constant yield depending on microstructure and maleic anhydride concentration. On the other hand in decahydronaphtalene at 130 °C, the reaction was very fast with very high yields. Nevertheless, in the range from 150 to 180 °C, the amount of linked anhydride in the final products did not exceed 11% (w/w) probably because of a decarboxylation of the maleinized products favoured by decahydronaphtalene.

A polyether, moisture curable, polyurethane resin was used as an adhesive on plastic and aluminium substrates, in order to investigate the influence of the surface properties on adhesion. The curing kinetics of the adhesive, in controlled temperature and humidity conditions, was evaluated and an elastomeric product was obtained after curing. The surface properties of the cured resin and of the different substrates (PPO/PA6 blend, polypropylene and aluminium) were evaluated and compared by using a contact angle technique. Adhesion measurements were performed using single-lap joints; the strength values obtained were correlated to the structure of the adhesive and to the surface treatments performed on the substrates.

The capillary rise method was applied to evaluate the improvement in water uptake of polyester and acrylic fabrics obtained by plasma treatment. Power, exposure time and gas type (nitrogen, air and oxygen) were considered as plasma variables. After plasma treatment, fabric samples were tested through capillary rise of water. The processing of a set of height absorption values vs. time, until equilibrium is reached, allows characterisation of the wettability of samples by three parameters. The influence of plasma variables on these parameters was studied.

Coal fly ash was characterized at first in batch adsorption with acid and basic dyes. Good results of removal were obtained, although strongly dependent on initial dye concentration, ash dosage, and above all on pH of the solution. The maximum adsorption capacities per g of fly ash were 410 mg of Acid Blue 25 and 142 mg of Basic Blue 9, both with an ash dosage of 2 g/L at pH 11 after a contact time of 1 h. However, increasing the ash dosage to 20 g/L and contact time to 24 h, the maximum adsorption capacity of Basic Blue 9 raised 187 mg/g fly ash at pH 11, but this value was lowered to 8.4 mg/g at pH 7. Afterwards, flow experiments were carried out in semi-batch mode with a fixed amount of ash and continuous flow of dye solution in continuous stirred tank reactor, to determine the exhaustion curves of fly ash. The best fit of the results was obtained by a sigmoidal function referable to the breakthrough curve model of Yoon-Nelson. Successively, to reduce the alkali leaching by solution flow, in a semi-pilot scale plant, a continuous stream of dye solution was mixed in stirred tank reactor with a continuous ash slurry supply, and the resulting slurry was decanted in a settling tank to obtain a clarified supernatant stream outlet. In this last equipment, the optimum conditions were investigated to obtain the highest yields of dye removal from solutions at low concentrations (5–20 mg/L) such as those occur in rinsing waters arising from dyeing processes.

The aim of the work was to improve wool’s dyeability using acid dye through a simple pretreatment with ultraviolet (UV) irradiation. Different radiation doses were investigated using both a laboratory UV lamp and a semi-industrial apparatus. UV-treated fabrics were characterized in terms of morphological, chemical and physical properties by SEM, FTIR-ATR spectra, water contact angle measurements, bursting and pilling test. The pre-treated samples were then dyed with an acid dye at different dyeing temperatures to compare the results with the untreated fabric. Final bath exhaustion reached, kinetic curves and colour measurements were evaluated. Moreover, the colour levelness of the dyeings obtained on fabrics with and without irradiation was assessed. Finally, dyeing fastness to washing and rubbing were determined according to ISO standard methods.

The possibility of reducing the use of auxiliaries in conventional cellulose acetate dyeing with Disperse Red 50 using ultrasound technique was studied as an alternative to the standard procedure. Dyeing of cellulose acetate yarn was carried out by using either mechanical agitation alone, with and without auxiliaries, or coupling mechanical and ultrasound agitation in the bath where the temperature range was maintained between 60 and 80 °C. The best results of dyeing kinetics were obtained with ultrasound coupled with mechanical agitation without auxiliaries (90% of bath exhaustion value at 80 °C). Hence the corresponding half dyeing times, absorption rate constants according to Cegarra–Puente modified equation and ultrasound efficiency were calculated confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound added to mechanical agitation was evidenced by the lower value (48 kJ/mol) in comparison with 112 and 169 kJ/mol for mechanical stirring alone with auxiliaries and without, respectively. Finally, the fastness tests gave good values for samples dyed with ultrasound technique even without auxiliaries. Moreover color measurements on dyed yarns showed that the color yield obtained by ultrasound-assisted dyeing at 80 °C of cellulose acetate without using additional chemicals into the dye bath reached the same value yielded by mechanical agitation, but with remarkably shorter time.

The aim of this study was the surface modification of wool fibers to confer a multifunctional finishing to the fabrics, improving the textile value and its applications without damage of comfort properties. The attention was focused on an economical and environmental friendly process to obtain an effective treatment with good durability to washing. Chitosan in acetic acid solution was applied by padding, and grafted by ultraviolet radiation, through radical reactions promoted by a photoinitiator. 2% chitosan grafted was enough to confer satisfactory antimicrobial activity (67% reduction of Escherichia coli) after an oxidative wool pre-treatment and 1h impregnation at 50 °C. Moreover treated wool fabrics showed a strong dyeability increase toward acid dye. However the evaluation of the treatment durability to laundering showed different behavior depending on the nature of the surfactants. Finally, anti-felting properties with respect to untreated fabrics were revealed, while no effect was shown toward anti-pilling properties.

The purpose of this work was to develop a textile finish based on radical UV-curing of chitosan on cotton and silk to confer antimicrobial properties. Fabrics were impregnated with a solution of 2% w chitosan in aqueous acetic acid (2% v/v) added of 2-hydroxy-2-methylphenylpropane-1-one (2% w/w with respect to chitosan) as photoinitiator and cured at room temperature by exposure to UV lamp for 60 s on both the sides. The antimicrobial activity of finished fabrics was tested according to ASTM standard test performed with Escherichia coli . Obtained results showed a strong antimicrobial activity conferred by the treatment, homogeneous on fabric surface, without affecting the hand properties of fabrics due to the low chitosan weight on (about 2%). The treatment durability to domestic laundering was tested after 5 cycles using either anionic or nonionic detergents. The antimicrobial activity resulted completely maintained after washing with a nonionic surfactant, while with anionic detergents the treatment durability was better for samples prepared with a deeper penetration of chitosan inside the fibers. The fabrics were characterized by dyeing tests, SEM and FTIR-ATR analyzes.

In this study, mats made of randomly oriented pure keratin nanofibres (~400 nm diameter) were prepared by electrospinning and tested for Cu2+ adsorption. Batch adsorption tests were carried out at pH 6, with different Cu2+ concentrations and contact times. The adsorption capacity and the removal efficiency are higher than those of conventional wool fabrics. This behaviour is due to the higher specific surface area of the nanofibres. By using an adsorbent dosage (mass of adsorbent/volume of the solution) of 1 g/L, the maximum adsorption capacity was 20 mg/g. The adsorption isotherm of the nanofibre mats fitted the Langmuir equation and the separation factor (RL, calculated to evaluate the adsorption efficiency, falls between 0 and 1 denoting a favourable adsorption. The mean free energy adsorption (E) evaluated applying the Dubinin-Radushkevich model is 12.9 kJ/mol, proving that electrostatic interactions are potentially involved in the sorption process.

UV curing of perfluoro-alkyl-polyacrylate resins able to impart water as well as oil-repellency to cotton fabrics was studied in comparison with conventional thermal polymerization. The process was assessed through weight gain and gel content measurements while the properties conferred to cotton fabrics were determined in terms of water and oil contact angles, moisture adsorption, and water vapor permeability. The polymerization yields were of the same order (>80 %) of those obtained with thermal curing as well as the high contact angles with water (>127°) and oil (>118°) even at low resin add-on (3 %). UV cured resins yielded oil contact angles mostly higher than 120° denoting super oil-repellent surfaces. Moreover the water and oil-repellency was adequately maintained after washing. The moisture adsorption of finished fabrics was lower than that of untreated cotton, but slightly higher for UV cured than thermally treated fabrics. Water vapor transmission rate showed that the finish treatment, thermal as well as by UV curing, does not reduce the breathability of the original cotton. DSC analysis demonstrated that the fiber pyrolysis is affected by the polymer add-on, while FTIR-ATR spectra of all finished fabrics showed typical peaks of ester and C-F groups. XPS analysis showed small differences between thermal and UV curing coatings with each resin, while coatings with the lowest percentage of fluorine groups did not affect the water and oil-repellency.

Wastewater effluents from textile industry mainly contain dyes used in the dyeing or printing of textiles yarns or fabrics. A lot of technologies can be adopted for dye removal from wastewaters, including biological treatments based on activated sludge, adsorption on activated carbon, or membrane processes. Nevertheless, none of these methods is performing toward all classes of dyes; treatment plants of great dimensions and difficult handling can be required, while cost can be prohibitive. In the present study, dye adsorption was performed on low-cost fibrous cellulose materials, submitted to a cationization process using a quaternary ammonium reagent. These materials were characterized by FTIR–ATR spectroscopy, while the treatment efficiency was investigated through exhaustion and kinetic adsorption tests toward anionic dyes, such as acid, direct, reactive, and a cationic dye. Comparisons were carried out between treated and untreated samples, and with activated carbon. Best results were obtained with cationized cotton, both in linters or “tulle” fabric form, showing good performance toward all the investigated dyes. Tests in continuous flow confirmed the good behavior of these materials, but tulle fabric was better as filtration medium for a lower pressure drop. Finally, regeneration tests by bleaching were carried out finding that regenerated material maintained good adsorption power.

The possibility of reducing the temperature of conventional wool dyeing with an acid levelling dye using ultrasound was studied in order to reach exhaustion values comparable to those obtained with the standard procedure at 98 °C, obtaining dyed samples of good quality. The aim was to develop a laboratory method that could be transferred at industrial level, reducing both the energy consumption and fiber damage caused by the prolonged exposure to high temperature without the use of polluting auxiliary agents. Dyeings of wool fabrics were carried out in the temperature range between 60 °C and 80 °C using either mechanical or ultrasound agitation of the bath and coupling the two methods to compare the results. For each dyeing, the exhaustion curves of the dye bath were determined and the better results of dyeing kinetics were obtained with ultrasound coupled with mechanical stirring. Hence the corresponding half dyeing times, absorption rate constants according to Cegarra–Puente modified equation and ultrasonic efficiency were calculated in comparison with mechanical stirring alone. In the presence of ultrasound the absorption rate constants increased by at least 50%, at each temperature, confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound was ascribed to the pre-exponential factor of the Arrhenius equation. It was also shown that the effect of ultrasound at 60 °C was just on the dye bath, practically unaffecting the wool fiber surface, as confirmed by the results of SEM analysis. Finally, fastness tests to rubbing and domestic laundering yielded good values for samples dyed in ultrasound assisted process even at the lower temperature. These results suggest the possibility, thanks to the use of ultrasound, to obtain a well equalized dyeing on wool working yet at 60 °C, a temperature process strongly lower than 98 °C, currently used in industry, which damages the mechanical properties of the fibers.

Chitosan grafting onto silk was tested with three crosslinking agents: trifunctional epoxy resin Araldite DY-T, PEG400 dimethacrylate, and glutaraldehyde in acetic as well as in tartaric acid solutions. Operating conditions were studied to obtain a significant silk weighting with satisfactory graft yields. With the epoxy crosslinker the weight gain was in the range from 1.8 to 8.8 % with graft yield from 8 to 23 %. In the case of PEG400DMA weight gain was 8–12 % with 22–24 % graft yield. With glutaraldehyde in tartaric acid solution a maximum weight gain of 8.4 % with 27.6 % graft yield was obtained. Results of determination of primary amino groups on the grafted silk showed that with epoxy and glutaraldehyde, unlike PEG400DMA, the amino groups of chitosan were only partially involved in crosslinking. Results of DSC analyses suggested that the modification of fibroin structure in chitosan-grafted silk was stronger with glutaraldehyde than with epoxy or dimethacrylate. FTIR-ATR spectra of grafted fibers were found very similar to that of control silk with an additional weak peak ascribable to chitosan in 1180–1080 cm−1 range. Surface investigation through AFM showed clear morphology differences between chitosan-grafted silk with epoxy or dimethacrylate and that crosslinked with glutaraldehyde; the latter appears uneven and scale-like, the others slightly rougher than the original silk.

Batch adsorption from aqueous solutions in a slightly basic medium of Methylene Blue, up to 2500 mg/L, onto synthetic magnesium silicate (Florisil) of three particle size ranges (mean diameters of 112, 200 and 425 microm) was compared to the corresponding adsorption onto activated carbon and Amberlite XAD-2. The best fit of the kinetic results was achieved by a pseudo second-order equation. The equilibrium data were found to be well represented by the Langmuir isotherm equation. Amberlite XAD-2, an unspecific adsorbent capable of adsorbing exclusively through a surface effect, exhibited a poor dye uptake, confirming that the adsorption mechanism on Florisil was due to electrostatic attraction and ion exchange. Moreover, the comparison between Florisil and the other adsorbents was performed on the basis of the evaluation of the surface area and pore volume occupied by the adsorbed dye.

The coating of a plastic substrate (polycarbonate sheets) with different uv-curable system was investigated. Systems based on an epoxy-acrylate resin (bisphenol-A-diglycidyl-ether-diacrylate) or on bisphenol-A-diethoxy-diacrylate were used in the presence of different reactive diluents. Pull-off experiments indicated that the presence of a reactive diluent able to dissolve or swell the polycarbonate matrix increased the adhesion properties; poor adhesion values were obtained by using reactive diluents which did not dissolve the polymer. When vinyl-pyrrolidone (VP) was used asa reactive diluent, Fourier transform infra-red analysis indicated that the VP diffused ino the polycarbonate matrix. Dynamic mechanical thermal analyses performed on thin films of polycarbonate attributable to the two polymeric phases. In the presence of diluent, the tan regions attributable to the two polymeric phases. In the presence of VP diluent, the tan σ peak of the coating phase was broader, thus suggesting the presence of a transition layer between the two phases.

Electro-conducting doped polypyrrole was deposited by in situ oxidative polymerisation on PET non-wovens. Thermal properties were evaluated by means of DSC and TG in nitrogen and air. Flame resistance tests reveal that coated PET fibres resist to direct contact with fire. By thermal analysis, it was found that PPy reduces the temperature at which thermo-oxidative degradation of PET occurs. Polypyrrole-coated PET non-wovens were heated above the melting point of PET for 30 min. After the heating the fibres become brittle and frail, but SEM observations revealed that they maintained their fibrous shape. A loss of chlorine was found because of intense heating.

Keratin regenerated from wool and fibroin regenerated from silk were mixed in different proportions using formic acid as the common solvent. Both solutions were cast to obtain films and electrospun to produce nanofibers. Scanning electron microscopy investigation showed that, for all electrospun blends (except for 100% keratin where bead defects are present), the fiber diameter of the mats ranged from 900 (pure fibroin) to 160 nm (pure keratin). FTIR and DSC analysis showed that the secondary structure of the proteins was influenced by the blend ratios and the process used (casting or electrospinning). Prevalence of beta-sheet supramolecular structures was observed in the films, while proteins assembled in alpha-helix/random coil structures were observed in nanofibers. Higher solution viscosity, thinner filaments, and differences in the thermal and structural properties were observed for the 50150 blend because of the enhanced interactions between the proteins.

Research on the electrospinning of nanofibers has increased in recent years because of the number of potential applications in different areas, ranging from technical textiles (e.g., filters, composite reinforcements, and protective fabrics) to biomedical commodities and devices such as bandages, membranes, bioactive surfaces, and porous substrates for tissue engineering, for which biocompatible polymers play an essential role. In this work, wool keratin/poly(ethylene oxide) nanofibers were electrospun from aqueous solutions of polymer blends under different operating conditions. The filaments were characterized with scanning electron microscopy, Fourier transform infrared, and differential scanning calorimetry analyses and compared with films of the same materials produced via casting with the aim of investigating structural changes due to the electrospinning process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 863–870, 2007

Batch adsorption of Methylene Blue, up to 1000 mg L(-1), and Acid Blue 25, up to 500 mg L(-1), onto ground hazelnut shells was studied in comparison with sawdust of various species of wood, in order to explore the potential use of this material as low cost adsorbent for dye removal in dyehouse effluents. The adsorption kinetics was investigated according to Lagergren's model, but the best fit was achieved by a second order equation. The equilibrium data were processed according to Langmuir's model and higher adsorption capacity values towards both dyes were shown by hazelnut shells than wood sawdust. Moreover, fixed bed adsorption of Methylene Blue was performed on hazelnut shell columns and the breakthrough curves were determined by varying bed depth, flow rate and influent concentration. The data were processed according to Bohart-Adams model and the column performances could be predicted by the bed depth service time (BDST) approach.

Structural characteristics of keratin regenerated from water (KW) and from formic (KF) acid solutions were compared. Amino acid composition and molecular weight distribution of KW and KF samples were studied by high performance liquid chromatography (HPLC) and SDS-PAGE electrophoresis. Turbidity measurement showed that keratin dissolved in formic acid forms transparent and stable solutions and no flocculation occurs. In addition, because of its good solvation properties, studied by viscosity measurements, formic acid can be used as a co-solvent to prepare keratin-based blend solutions. Structural studies carried out by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and near infrared (NIR) suggest that formic acid stabilizes the beta-sheet structure. Thermogravimetric analysis (TGA) reveals a higher thermal stability of keratin regenerated from formic acid with respect to keratin regenerated from water. (c) 2007 Elsevier B.V. All rights reserved.

Blends of poly(ethylene oxide) (PEO) and keratin were prepared with the aim of obtaining bio-compatible materials suitable for film and fibre production. Aqueous keratin solutions, prepared by keratin extraction from wool with urea, m-bisulphite and sodium dodecyl sulphates (SDS), filtration and dialysis, were added with different amounts of PEO and solid films were prepared by casting. The addition of SDS prevents protein aggregation. Morphological, thermal and spectroscopic analysis of the films pointed out that keratin hinders the PEO crystallization process, since a progressive decrease in the size of PEO spherulites is observed and the melting point and the related enthalpy decrease with increasing the keratin content. On the other hand, according to thermal and spectroscopic investigations. PEO seems to interfere with the keratin self-assembling giving the protein a different thermal behaviour.

Liquid polybutadienes were epoxidized with hydrogen peroxide-acetic acid confirming the influence of the microstructure on the epoxy content. Thermal cross-linking of the epoxidized products was studied by DSC and a different behaviour due to epoxy content as well as to microstructure was found. A correlation between enthalpy/epoxy ratio and vinyl content was also observed. The addition of a radical initiator as dicumyl peroxide (DCP) yielded exothermal effects of cross-linking in the original polybutadienes, confirming the higher reactivity of the vinyl groups. In the epoxidized products, the introduction of DCP gave a peak split, which was explained by the overlap of two cross-linking mechanisms, due to residual double bonds and epoxy groups. From the DSC data, the isothermal curves of cross-linking conversion were calculated as a function of time, for a better comparison of the performances and properties of the epoxidized polybutadienes.

The kinetics of the reaction of maleic anhydride with liquid polybutadienes of various microstructures was studied by using differential scanning calorimetry (DSC). The kinetic results of thermal maleinization show a dependence from m.w. and polybutadiene microstructure. The introduction of a gel inhibitor as copper naphthenate has proved that crosslinking reactions also occur during the maleinization. On the other hand, the maleinization in the presence of a radical initiator as dicumyl peroxide (DCP) shows thermal effects higher than pure thermal reaction with a partial overlap of the calorimetric peaks due to maleinization and crosslinking.

The in situ polymerisation of acrylic acid using low temperature plasma treatment was carried out on polyester, polyamide and polypropylene fabrics with the aim of improving their dyeability with basic dyes. The overall colour strength obtained was significantly increased as a result of this treatment. However, while the wash fastness was acceptable on polyamide, it was unsatisfactory on polyester and polypropylene fabrics, probably due to lack of penetration of these fibres by the acrylic acid monomer. Scanning electron microscopy and Fourier transform infrared spectroscopy confirmed that grafting of polyacrylic acid had taken place only on the surface of the polyester and polypropylene fibres, but in the case of polyamide the interior of the fibre was also modified.

In the past, semiconductive textiles including yarns and fabrics, have been produced by incorporating conductive fillers (particularly carbon, metal powder or conductive polymers) into the fibre structure or by coating fibres with metals or thin films of conductive polymers. Incorporation of large amounts of conductive fillers results in a deterioration of mechanical properties and processing problems of the fibres. Conductive polymers, such as polypyrrole (Ppyr), deposited on textile substrates, are highly susceptible to oxidation and abrasion. Recent research carried out in our laboratories, shows that polypyrrole can be embedded in natural and man made cellulose-based fibres, such as cotton, viscose, cupro and lyocell, by means of internal polymerisation taking place in the amorphous region of the fibres. In this work, pyrrole was applied by simple finishing process at room temperature from an aqueous solution of the monomer that penetrates into the fibre similarly to a non-reactive dye. Subsequent polymerisation caused its permanent insolubility in the internal fibre structure, leading to high levels of fastness to washing and to light exposure, without significant modification of the mechanical properties. This low cost technological application is of particular interest for developing new technical apparel, such as antistatic fabrics for work clothing, sportswear, heating and cooling equipment, etc.

A series of poly(propylene-glycol-diacrylates) (PPGDA) having molecular weights (MW) in the range 300–3,000 and an acrylic functionality near to two were synthesized by acrylation of the corresponding hydroxy-terminated oligomers with acrylic acid in the presence of p-toluensulphonic acid as a catalyst. The M¯n of the acrylated products was found slightly lower than that of the starting oligomers, indicating the occurrence of an acidic degradation reaction which does not influence the acrylic functionality. The acrylated oligomers were ultraviolet (UV) cured until a complete double bond disappearance was obtained: only in the presence of tripropylene-glycol-diacrylate (TPGDA) were small amounts of residual unsaturations revealed. Rubbery materials were usually obtained, with the exception of TPGDA. The properties of the cured PPGDA were investigated by means of differential scanning calorimetry, thermomechanical analysis, and dynamic mechanical thermal analysis. The Tg values were found to decrease by increasing the MW of the used oligomers, that is, by increasing the length of the chain between the two acrylic double bonds. A good agreement with the Nielsen equation was found. Moreover, the equilibrium swelling values in water were measured; the obtained values were interpreted in terms of the solubility parameters of the oligomers and of the crosslinking density of the networks. Finally, some mixtures of PPGDA oligomers with a typical epoxy-acrylate resin were UV cured; their properties confirm the high flexibilizing effect of the PPGDA oligomers. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:491–497, 1997