Manel Lis
Universitat Politecnica de Catalunya, Chemical Engineering, Faculty Member
- Pharmacology, Pharmacokinetics, Transdermal Drug Delivery System, Extended Release Formulations, Infectious Diseases, Gastrointestinal Drug Therapy, and 19 moreColloids and Surfaces, Nanotechnology, Materials Science, Chemical Engineering, Surface Chemistry, Surface Science, Microemulsions, Nanoscience, Pharmacotherapy, Reaction Engineering Course, Industrial Chemistry/Chemical Engineering, Chemical Reaction Engineering, Mechanisms of Heterogeneous Catalytic Reactions, Heterogeneous Catalysis, Catalyst, Chemical Kinetics, Reaction mechanisms and Catalysis, Chemical Reaction Engineering and Reactor Analysis, Self Assembly, and Libros Digitales(Colloids and Surfaces, Nanotechnology, Materials Science, Chemical Engineering, Surface Chemistry, Surface Science, Microemulsions, Nanoscience, Pharmacotherapy, Reaction Engineering Course, Industrial Chemistry/Chemical Engineering, Chemical Reaction Engineering, Mechanisms of Heterogeneous Catalytic Reactions, Heterogeneous Catalysis, Catalyst, Chemical Kinetics, Reaction mechanisms and Catalysis, Chemical Reaction Engineering and Reactor Analysis, Self Assembly, and Libros Digitales)edit
- Chemical Engineer, Master in Engineering and PhD on Mass and Energy Transport in Polymers Teaching Chemical Engineeri... moreChemical Engineer, Master in Engineering and PhD on Mass and Energy Transport in Polymers Teaching Chemical Engineering since 1984. ESEIAAT.UPCMember of INTEXTER. UPCResearch Group POLQUITEX. Focussed on the physico-chemical aspects on Drug-Delivery Systems based on polymeric structuresHead of Surfactants and Detergency Laboratory at INTEXTER-UPC(Chemical Engineer, Master in Engineering and PhD on Mass and Energy Transport in Polymers Teaching Chemical Engineering since 1984. ESEIAAT.UPCMember of INTEXTER. UPCResearch Group POLQUITEX. Focussed on the physico-chemical aspects on Drug-Delivery Systems based on polymeric structuresHead of Surfactants and Detergency Laboratory at INTEXTER-UPC)edit
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We investigated the performance of cotton fabrics coated with DOPO-HQ and Zr-based Metal–organic Frameworks when exposed to fire. The chemical structure of the cotton fabrics before and after the coating was characterized using FTIR... more
We investigated the performance of cotton fabrics coated with DOPO-HQ and Zr-based Metal–organic Frameworks when exposed to fire. The chemical structure of the cotton fabrics before and after the coating was characterized using FTIR spectroscopy, and the surface morphology of cotton and their combustion residues was probed via scanning electron microscopy. In our experiments, we used flammability tests and thermogravimetric methods to understand the burning behavior of the coated fibers, as well as their thermal stability. The cotton fabrics coated with DOPO-HQ and Zr MOFs exhibited shorter combustion times, had better thermal degradation properties, promoted the creation of heat-insulating layers, and exhibited improved smoke suppression behavior.
Research Interests: Polymers()
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The textile fiber made of poly(trimethylene terephthalate) came onto the market a few years ago. This fiber has certain advantages over traditional polyester, especially its greater elasticity and the fact that it can be dyed at lower... more
The textile fiber made of poly(trimethylene terephthalate) came onto the market a few years ago. This fiber has certain advantages over traditional polyester, especially its greater elasticity and the fact that it can be dyed at lower temperatures. Here we study the dyeing kinetics of this “new” fiber using an azo disperse dye, C.I. Disperse Red 82, observing that the dyeing rate increases with temperature and that dyebath exhaustions only reach acceptable levels at temperatures above 80 °C. In order to quantify and compare the experimental data obtained, three kinetics models have been chosen. To fit results with models, non-linear regression methods have been applied and, to differentiate between early and final stages, two levels of exhaustion have been checked. From results obtained with the Chrastil model, apparent diffusion coefficients and the activation energy of diffusion have been calculated.
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In this work, the antioxidant gallic acid (GA) has been encapsulated in microspheres prepared with poly-ε-caprolactone (PCL) and incorporated into polyamide (PA) obtaining the cosmeto-textile. The topical application of the... more
In this work, the antioxidant gallic acid (GA) has been encapsulated in microspheres prepared with poly-ε-caprolactone (PCL) and incorporated into polyamide (PA) obtaining the cosmeto-textile. The topical application of the cosmeto-textile provides a reservoir effect in the skin delivery of GA. The close contact of the cosmeto-textile, containing microsphere-encapsulated GA (ME-GA), with the skin and their corresponding occlusion, may be the main reasons that explain the crossing of active principle (GA) through the skin barrier, located in the stratum corneum, and its penetration into the different compartments of the skin, epidermis and dermis. An ex vivo assessment was performed to evaluate the antioxidant effect of the ME-GA on the stratum corneum (SC) using the thiobarbituric acid-reactive species (TBARS) test. The test is based on a non-invasive ex vivo methodology that evaluates lipid peroxides formed in the outermost layers of the SC from human volunteers after UV radiation ...
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Oregano essential oil was encapsulated in poly-ϵ-caprolactone nanoparticles by a nanoprecipitation method using glycerin as a moisturizer. Nanocapsule characterization was performed by measuring the particle size, colloidal stability and... more
Oregano essential oil was encapsulated in poly-ϵ-caprolactone nanoparticles by a nanoprecipitation method using glycerin as a moisturizer. Nanocapsule characterization was performed by measuring the particle size, colloidal stability and encapsulation efficiency using dynamic light scattering, UV–Vis spectrophotometry and scanning electron microscopy (SEM). The nanoparticles had a mean particle size of 235 nm with a monomodal distribution. In addition, a low polydispersity index was obtained, as well as a negative zeta potential of −36.3 mV and an encapsulation efficiency of 75.54%. Nanocapsules were applied to polyester textiles through bath exhaustion and foulard processing. Citric acid and a resin were applied as crosslinking agents to improve the nanocapsules’ adhesion to the fabric. The adsorption, desorption, moisture content and essential oil extraction were evaluated to determine the affinity between the nanocapsules and the polyester. The adsorption was higher when the citr...
Research Interests: Polymers()
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Differences in hydrolysis behaviour between lyocell and viscose type regenerated celluloses (viscose and modal) have been evaluated by the study of the enzymic hydrolysis by cellulases. Kinetic parameters (Vem and ke) and enzyme catalytic... more
Differences in hydrolysis behaviour between lyocell and viscose type regenerated celluloses (viscose and modal) have been evaluated by the study of the enzymic hydrolysis by cellulases. Kinetic parameters (Vem and ke) and enzyme catalytic specificity were calculated during cellulase processing. The results show low adsorption, catalytic specificity and rate of hydrolysis (Vem=0.407 h/l h) of lyocell fibres ahead of the
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Metal-organic frameworks (MOFs) have great potential for the development of fire barriers for flammable materials. Accordingly, zirconium-based metal-organic framework (Zr-MOF), branched polyethyleneimine (BPEI), and vinyltriethoxysilane... more
Metal-organic frameworks (MOFs) have great potential for the development of fire barriers for flammable materials. Accordingly, zirconium-based metal-organic framework (Zr-MOF), branched polyethyleneimine (BPEI), and vinyltriethoxysilane (VTES) were deposited to produce composites assembled on cellulosic fibers to investigate their barrier effects. The structure, morphology, and thermal properties of the cellulosic fibers were characterized using FTIR spectroscopy, SEM, and TGA. Compared with the untreated cotton sample, the temperature of the maximum rate of weight loss (Tmax) of C-Zr-MOF/BPEI/VTES increased from 479 to 523.3 °C and the maximum weight loss rate (Rmax) at Tmax decreased from 37.6 to 17.2 wt%/min. At 800 °C, the pristine cotton was burned out without residues whereas the residual char content of the C-Zr-MOF/BPEI/VTES sample was 7.2355 wt%. From the vertical burning tests, the results suggested that the C-Zr-MOF/BPEI/VTES sample had better barrier effects by reducing...
Research Interests: Polymers()
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RESUMEN El mercerizado es uno de los tratamientos más importantes que se realizan sobre las fibras celulósicas, para mejorar las propiedades de estabilidad dimensional y accesibilidad. El objetivo del trabajo es el de estudiar el efecto... more
RESUMEN El mercerizado es uno de los tratamientos más importantes que se realizan sobre las fibras celulósicas, para mejorar las propiedades de estabilidad dimensional y accesibilidad. El objetivo del trabajo es el de estudiar el efecto que produce el tratamiento de mercerizado, con diferentes concentraciones de hidróxido sódico, sobre las propiedades mecánicas de tracción (alargamiento, módulo de Young, tenacidad y trabajo de rotura) de muestras de hilo compuesto por fibras obtenidas por hilatura en óxido de N-metilmorfolina (NMMO), las cuales se denominan genéricamente lyocell. Los resultados experimentales indican que se produce una disminución progresiva de las propiedades mecánicas hasta una concentración 4,18 M de NaOH, manteniéndose constante el comportamiento a partir de este valor. Esta modificación en el comportamiento es consecuencia de los cambios estructurales y de cristalinidad producidos en la fibra. Palabras clave Lyocell, propiedades mecánicas, mercerizado. 1. INTRO...
La récente apparition de cette fibre présente les avantages d’un procédé de fabrication moins polluant que celui de la viscose conventionnelle, tout en améliorant les propriétés de résistance et de ténacité en milieu humide. Le... more
La récente apparition de cette fibre présente les avantages d’un procédé de fabrication moins polluant que celui de la viscose conventionnelle, tout en améliorant les propriétés de résistance et de ténacité en milieu humide. Le comportement de la fibre lyocell par rapport à l’absorption de colorants directs revêt une certaine importance dans la phase de teinture correspondante, pendant le traitement chimique et industriel de cette fibre. L’étude vise à caractériser les paramètres influents dans le processus d’absorption de colorants directs sur les fibres de lyocell, à partir de l’analyse des isothermes d’absorption dans l’équilibre du colorant C.I. Direct Blue 1. A partir des résultats expérimentaux, nous avons déterminé les équations d’équilibre pour l’interprétation du comportement du système en faisant une analyse comparative des équations proposées par Nernst, Freundlich et Langmuir et nous avons calculé le volume libre interne caractéristique de la fibre lyocell, V(l/kg). Nous...
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Dyes are complex molecules that can sometimes cause damage to the aquatic environment and harm human health. They are often not completely removed from effluent by the usual treatments; therefore, ...
Research Interests: Textile()
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ABSTRACT
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The most efficient way to hydrolyse cellulose from wheat straw is by enzymic hydrolysis, which can be improved by different pretreatments of the substrate. The enzyme kinetics of alkali (sodium hydroxide) pretreated wheat straw was... more
The most efficient way to hydrolyse cellulose from wheat straw is by enzymic hydrolysis, which can be improved by different pretreatments of the substrate. The enzyme kinetics of alkali (sodium hydroxide) pretreated wheat straw was studied using different concentrations of a commercial cellulase enzyme (6.25–75g/L). This pretreatment increased hydrolysis compared to untreated wheat straw. The influence of enzyme concentration on the production of reducing sugars was studied from two different theoretical approaches. In the first, the hydrolysis model and kinetic parameters (maximal velocity, Vemax, and half-saturation constant, Ke) were determined from initial velocities by an alternative approach to the classical Michaelis–Menten equation. In the second, the Chrastil approach is used, which is the study of all the time values from the rate of product formation, taking into account that in a heterogeneous system, these reactions are diffusion limited and the time curves depend strongly on the heterogeneous rate-limiting structures of the enzyme system.
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ꞵ-Cyclodetrin (ꞵ-CD) is an oligosaccharide composed by seven units of 20 D-(+)-glucopyranose joined by α-1,4 bonds, which is obtained from starch. Its singular trunk 21 conical shape organization with a well-defined cavity provides an... more
ꞵ-Cyclodetrin (ꞵ-CD) is an oligosaccharide composed by seven units of 20 D-(+)-glucopyranose joined by α-1,4 bonds, which is obtained from starch. Its singular trunk 21 conical shape organization with a well-defined cavity provides an adequate environment for a 22 several types of molecules to be included. The complexation changes the properties of the guest 23 molecules increasing its stability, bioavailability, protecting against degradation, reducing its 24 volatility, etc. Thanks to its versatility, biocompatibility and biodegradability ꞵ-CD is widespread 25 in many researches and industrial applications. In this review, we summarize the role of ꞵ-CD and 26 its derivatives in the textile industry. First we present some general physicochemical characteristics 27 followed by its application in the areas of dyeing, finishing and wastewater treatment. The review 28 covers since the role of ꞵ-CD as auxiliary agent on dyeing, as matrix to dye adsorption until the 29 chemical modificat...
Biofunctional textiles are materials that exert a biological effect on human skin. Such textiles constitute the basis for the delivery system of cosmetic or pharmaceutical substances when the textile comes into contact with skin. The... more
Biofunctional textiles are materials that exert a biological effect on human skin. Such textiles constitute the basis for the delivery system of cosmetic or pharmaceutical substances when the textile comes into contact with skin. The actives are commonly incorporated in vehicles which may break when the garment rubs the skin allowing the release of the compounds directly in order to be absorbed by the skin. These biofunctional textiles may help, for example, people with sensitive skin, to whom the active substance can slowly be released onto the skin. In fact, there are already several textile products in the market claiming that they have several properties that are usually found in cosmetics (1), such as moisturizing, slimming, energizing, refreshing, relaxing, vitalising, UV protecting or just simply perfumed. There is a real need to develop test methods to check the effectiveness and durability of the claimed properties (2). Active principle microencapsulation not only solves th...
The aim of the chapter is to state different new possibilities that textile substrates offer for more specialized functions as Biomedical devices, Cosmetics, Skin treatment, and which are the mechanisms involved in such new applications.... more
The aim of the chapter is to state different new possibilities that textile substrates offer for more specialized functions as Biomedical devices, Cosmetics, Skin treatment, and which are the mechanisms involved in such new applications. How to quantify the transport phenomena from the substrate to the skin, or to surrounding different medium, in which they have to be used. Textiles are covering 80% of the human body and a big percentage of that is in close contact with skin. If the system of vehiculization of the active principles is, carefully, designed, the reservoir effect of the polymeric chains of fibers can play a very interesting role in the delivery of the active principle. Microencapsulation, lipidic aggregates and nanofibers, have shown very promising experimental results. These results will help to other researchers to develop, more accurate systems, which will valorize textile substrates, fibers and tissues for the use in more sophisticated fields.
The hydrophilicity of fibers is directly related to the comfort of a fabric and represents one of the most important aspects of a textile. Therefore, polyester (PES) modification has focused on an increase in moisture content and a... more
The hydrophilicity of fibers is directly related to the comfort of a fabric and represents one of the most important aspects of a textile. Therefore, polyester (PES) modification has focused on an increase in moisture content and a subsequent improvement of the user’s experience. Based on the glycerol hygroscopic properties, the main objective has been the enhancement of the hydrophilicity of polyester by glycerol treatments. Furthermore, microwave irradiation and alkaline treatment have been applied, in order to increase glycerol adhesion. Treated PES samples were characterized by performing moisture content, negative ion, water diffusion and water vapor resistance analyses. The effect of different treatment conditions such as bath ratio (1/10 or 1/15), temperature (40, 60 or 100 °C), time (2 or 5 min) and microwave radiation intensity (300 or 500 W) was evaluated. The moisture content of treated PES results indicated that by decreasing the bath ratio and increasing the time and te...
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Las presiones medioambientales sobre la industria textil y el consumo de agua y energia de dicho sector, llevan a la adopcion de medidas que influyen directamente sobre los procesos industriales de tintura. Disminuir el impacto... more
Las presiones medioambientales sobre la industria textil y el consumo de agua y energia de dicho sector, llevan a la adopcion de medidas que influyen directamente sobre los procesos industriales de tintura. Disminuir el impacto medioambiental optimizando procesos para conseguir mejorar el nivel de agotamiento y/o reutilizar los banos finales, con o sin tratamiento intermedio, son algunas de las medidas que se vienen aplicando. En este trabajo se estudiara el caso de reutilizaciones directas de banos de tintura con CI Azul Disperso 56 y microfibras de poliester, con el objeto de evaluar su comportamiento en cineticas no isotermicas en el caso de 25 reutilizaciones a partir del bano original. A partir de los resultados obtenidos puede observarse una tendencia del % de agotamiento con el numero de reutilizaciones. Disminuye hasta la 5o reutilizacion, manteniendose aproxima-damente constante des de la 6a hasta la numero 25.
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Abstract Hemp (Cannabis sativa L.) is a plant of which, its ease of cultivation, structure and properties, provide it great potential for industrial applications; nevertheless, the unfavorable content of lignin complicates its processing,... more
Abstract Hemp (Cannabis sativa L.) is a plant of which, its ease of cultivation, structure and properties, provide it great potential for industrial applications; nevertheless, the unfavorable content of lignin complicates its processing, especially in the textile area. Thus, an appropriate knowledge of the delignification process would lead to treating hemp fibers as cotton fibers. In this work, hemp has been treated with an alkaline liquor [NaOH 1 M] at 110 °C during different times and afterwards, the substrates were chemically characterized in order to determine their lignin content and also analyzed by thermogravimetry (TGA). Through the correlation analysis, the relationship between lignin content, onset temperature of cellulose decomposition and loss of mass at the different decomposition steps were established. A hyperbolic kinetic model to explain the influence of alkaline treatment time on lignin content and also on the loss of mass at the four steps of decomposition of the samples by TGA up to 600 °C has been developed. Although it has been found that the degradation of lignin occurred across the entire temperature range, results have shown that the influence of treatment time has become clearly relevant on lignin content, Step2 (180.5 °C-273.5 °C) where a fraction of 10 to 16% of lignin was degraded, and Step3 273.5 °C-396.5 °C) where cellulose was mainly decomposed and 20% of lignin was also degraded.
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Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain Textile Research Institute of Terrassa (INTEXTER), Universitat Politècnica de Catalunya, Terrassa, Spain “Josep Carilla” Thermal Analysis and Calorimetry... more
Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain Textile Research Institute of Terrassa (INTEXTER), Universitat Politècnica de Catalunya, Terrassa, Spain “Josep Carilla” Thermal Analysis and Calorimetry Laboratory (IQAC-CSIC), Barcelona, Spain Statistics and Operations Research Department, Universitat Politècnica de Catalunya, Terrassa, Spain Cosmetic and Textile Innovations Group (IQAC-CSIC), Barcelona, Spain
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Abstract The microencapsulation of essential oils and its application in textile articles allows the aggregation of different functionalities to the substrates, imparting them antimicrobial properties, cosmetic effects, UV protection,... more
Abstract The microencapsulation of essential oils and its application in textile articles allows the aggregation of different functionalities to the substrates, imparting them antimicrobial properties, cosmetic effects, UV protection, application of drugs, among others. Therefore, the coacervation technique allows good results using starch to prepare the microcapsules. The objective of this work was the microencapsulation of Aloe Vera with cornstarch using the simple coacervation technique in cotton nonwoven fabric using butane tetracarboxylic acid (BTCA) as a binding agent. Optical and Scanning electron microscopy were performed to understand the morphology of the microcapsules obtained; thermogravimetry, to the comprehension of the thermal degradation of the microcapsules; mass gain percentage; FTIR was used to prove the interaction between nonwoven and microcapsule and finally, the CIE WI white index. The micrography allowed the observation of granular morphology, predominantly angular. The thermogravimetric curves have shown two significative thermal events: dehydration of the oil and degradation of the starch. The samples presented darker coloration; however, their quality was not compromised by the finishing. For this reason, the characterizations allowed to infer that the simple coacervation using this method is a simple process, with good results for the encapsulation of essential oils.
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Abstract The use of biopolymers such as cyclodextrin in textiles for the development of biofunctional fabrics is an alternative for the development of eco-friendly textiles. Cyclodextrins can create covalent interactions with the chemical... more
Abstract The use of biopolymers such as cyclodextrin in textiles for the development of biofunctional fabrics is an alternative for the development of eco-friendly textiles. Cyclodextrins can create covalent interactions with the chemical groups available in wool, allowing the sorption of active molecules that will be released, such as the citronella oil. Therefore, this work investigates the formation of cyclodextrin complex oil applied in wool and its release mechanism. The complexes obtained and grafted to the fabric. New microstructures formed have been characterized using instruments as TGA, DLS, FTIR-ATR and SEM, besides the verification of the durability of the finish and the cytotoxicity of the obtained fabric. The release of citronella oil was, also analyzed and mathematical adjustments were performed using the approach proposed by Korsmeyer-Peppas in order to verify the release mechanisms. Results have indicated the formation of the complex and its fixation by covalent bonding, according to the FTIR-ATR specter and SEM images, have shown an non-fickian, but controlled, release profile. For this reason, the application of the complexes in wool fabrics shows promising options for the design and production of eco-friendly biofunctional materials for controlled release, allowing the oil properties to be used in textile matrices.
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Abstract Essential oils are complex, volatile liquid mixtures that can be extracted from various parts of plants. Their main characteristics are strong fragrance and biological properties. Studying the characteristics of oils along with... more
Abstract Essential oils are complex, volatile liquid mixtures that can be extracted from various parts of plants. Their main characteristics are strong fragrance and biological properties. Studying the characteristics of oils along with the possibility of an interaction with textiles creates new possible uses of this material. However, when oil is applied to a textile substrate, it is necessary to develop an oil release model, while most of the works only explore the application procedure and the fixed oil durability against washes. Thus, this work reports the mechanism and kinetics of controlled release of microencapsulated citronella oil from wool. The microencapsulation was done by complex coacervation with gelatin and gum Arabic biopolymers as shell materials. Optical microscopy, scanning electron microscopy and Fourier-transform infrared spectroscopy were used to confirm the encapsulation. The microcapsules were then supported by foulard in wool, fixed on fabrics and evaluated by attenuated total reflection Fourier-transform infrared spectroscopy. The controlled release of citronella from the microcapsules deposited on the fabric was studied in vitro. The microcapsules formed had a multi-core structure, and when applied to wool they showed diffusion by a Fickian mechanism in the first release stage and on the second stage changed to non-Fickian kinetics. The controlled release indicates that the textile structure influences the release model due to an interaction between fabric and water.
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Microencapsulated finishes are an important element in the development of new textiles. In this context, a large area to be explored is microencapsulation of essential oils in textiles. This technique offers the possibility of developing... more
Microencapsulated finishes are an important element in the development of new textiles. In this context, a large area to be explored is microencapsulation of essential oils in textiles. This technique offers the possibility of developing new products with many advantages over traditional fabrics, as traditional finishing may be ineffective for reasons related to uncontrolled release of the active principle while microencapsulation aims to achieve increased duration of the finishing effect. However, many studies present only the application of microcapsules in a textile but do not report how the release of the encapsulated material occurs or the influence of the textile matrix. This paper reports the mechanism and kinetics of controlled release of microencapsulated citronella oil in cotton and polyester. The microencapsulation was done by complex coacervation with gelatin and gum Arabic as shell materials. The resulting microcapsules were analyzed by optical microscopy, scanning electron microscopy, thermogravimetric analysis, and dynamic light scattering. They were then applied in cotton and polyester and evaluated by attenuated total reflection Fourier-transform infrared spectroscopy. Finally, the controlled release of citronella from the microcapsules deposited on the fabrics was studied in vitro. It was found that the release was directly influenced by the type of fiber: the microcapsules in polyester showed diffusion by a Fickian mechanism, while a non-Fickian kinetic model fit for the modified cotton. Comprehension of such controlled release processes is fundamental for achieving and developing more durable finishing effects.
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ABSTRACT Treating Lyocell fibers with cellulases has become an indispensable step in dyeing and finishing these fibers, even though the effectiveness and influence of such treatment can only be evaluated qualitatively. This paper presents... more
ABSTRACT Treating Lyocell fibers with cellulases has become an indispensable step in dyeing and finishing these fibers, even though the effectiveness and influence of such treatment can only be evaluated qualitatively. This paper presents a quantitative evaluation of the effect of cellulases on Tencel fibers and studies the influence of initial concentration and treatment time. Results are then used to establish a mathematical model that relates the level of attack with concentration and time.
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The primary advantages of electrospun membranes include the ability to obtain very thin fibers that are on the order of magnitude of several nanometers with a considerable superficial area and the possibility for these membranes to be... more
The primary advantages of electrospun membranes include the ability to obtain very thin fibers that are on the order of magnitude of several nanometers with a considerable superficial area and the possibility for these membranes to be manipulated and processed for many different applications. The purpose of this study is to evaluate and quantify the transport mechanisms that control the release of drugs from polymer-based sandwich membranes produced using the electrospinning processes. These electrospun membranes were composed of poly(lactic acid) (PLA) because it is one of the most promising biodegradable polymers due to its mechanical properties, thermoplastic processability and biological properties, such as its biocompatibility and biodegradability. The transport mechanism that controls the drug delivery was evaluated via the release kinetics of a bioactive agent in physiological serum, which was used as a corporal fluid simulation. To describe the delivery process, mathematical models, such as the Power Law, the classical Higuchi equation and an approach to Fick's Second Law were used. Using the applied mathematical models, it is possible to conclude that control over the release of the drug is significantly dependent on the thickness of the membrane rather than the concentration of the drug.
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In order to provide another way of reducing the stock of used tyres and polyvinyl chloride waste, a new material is developed and studied. Formulation includes a matrix constituted by a compound of recycled polyvinyl chloride with... more
In order to provide another way of reducing the stock of used tyres and polyvinyl chloride waste, a new material is developed and studied. Formulation includes a matrix constituted by a compound of recycled polyvinyl chloride with plasticized polyvinyl chloride and a reinforcement of ground tyre rubber. Acoustic and mechanical properties of different compositions of polyvinyl chloride/ground tyre rubber were tested in order to determine their suitability for applications fulfilling industry requirements. Sound absorption has been analyzed, showing interesting results at frequencies higher than 2500 Hz. The obtained values are found to be depending on the thickness of the sample, the content of the ground tyre rubber and the existence of gaps, pores and voids either between layers or in the interphase between the matrix and reinforcement. From the study of the mechanical properties, we may observe that the ground tyre rubber act as filler, improving stiffness of polyvinyl chloride/gr...
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This study investigates the relationship between color perceptual attributes and color emotions, as well as the influence of different cultural backgrounds. Totally 214 color samples were evaluated on 12 emotion variables by subjects from... more
This study investigates the relationship between color perceptual attributes and color emotions, as well as the influence of different cultural backgrounds. Totally 214 color samples were evaluated on 12 emotion variables by subjects from seven different region groups in the psychophysical experiment. By factor analysis, it was found that three factors were sufficient to represent 80 “region-emotion” variables. For each variable, there is no distinct difference among different region groups. The 12 emotion variables could be divided into four categories, namely, activity index, potency index, definition index, and temperature index. Factor scores were further calculated to study the determinants on each factor. The analysis showed that the three factors were mainly related to chroma, lightness, and hue, respectively. It was concluded that chroma and lightness were the most important factors on color emotion, whereas the influences of hue and cultural background were very limited. © ...
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ABSTRACT Ceramides are the main constituents of the lipid lamellas present in the intercellular domains of the stratum corneum from human skin. They have a main role in the structure and the barrier function of the skin, which is... more
ABSTRACT Ceramides are the main constituents of the lipid lamellas present in the intercellular domains of the stratum corneum from human skin. They have a main role in the structure and the barrier function of the skin, which is fundamental in the sensitive skin. Recent studies have demonstrated that the liposome structures formed with internal wool lipids with a relevant amount of ceramides provide both a reinforcement of the barrier function of the skin and an increase of the cutaneous hydration (1, 2). The present project has been designed to obtain new smart textiles containing ceramides to confer a regenerative effect to the skin in contact with them based on their repairing properties of the barrier function. The experimental methodology used to achieve an appropriate application of the vehicles into textiles (polyamide or cotton) to obtain a gradual release of the active compounds (ceramides) is being investigated. The main aim is to provide a beneficial and repairing skin effect taking into account the existing friction between skin and textile. On the other hand, ethylhexyl methoxycinnamate have been encapsulated in different vehicles and used as reference probes to follow their fixation and release into the textiles.
Biofunctional textiles with integrated drug-delivery systems can help in the fight against vector-borne diseases. The use of repellent agents derived from plants and oils is an alternative to DEET (N,N-diethyl-m-methylbenzamide), which... more
Biofunctional textiles with integrated drug-delivery systems can help in the fight against vector-borne diseases. The use of repellent agents derived from plants and oils is an alternative to DEET (N,N-diethyl-m-methylbenzamide), which has disadvantages that include toxic reactions and skin damage. However, some researchers report that oils can be ineffective due to reasons related to uncontrolled release. In this work, the mechanism of control of citronella oil (OC) complexed with β-cyclodextrin (βCD) on cotton (COT) and polyester (PES) textiles was investigated. The results obtained reveal that finishing cotton and polyester with β-cyclodextrin complexes allows for control of the release mechanism of the drug from the fabric. To assess the complexes formed, optical microscopy, SEM, and FTIR were carried out; the yield of complex formation was obtained by spectroscopy in the ultraviolet region; and controlled release was performed in vitro. Oil complexation with βCD had a yield of ...
Research Interests: Polymers()
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β-Cyclodextrin (β-CD) is an oligosaccharide composed of seven units of D-(+)-glucopyranose joined by α-1,4 bonds, which is obtained from starch. Its singular trunk conical shape organization, with a well-defined cavity, provides an... more
β-Cyclodextrin (β-CD) is an oligosaccharide composed of seven units of D-(+)-glucopyranose joined by α-1,4 bonds, which is obtained from starch. Its singular trunk conical shape organization, with a well-defined cavity, provides an adequate environment for several types of molecules to be included. Complexation changes the properties of the guest molecules and can increase their stability and bioavailability, protecting against degradation, and reducing their volatility. Thanks to its versatility, biocompatibility, and biodegradability, β-CD is widespread in many research and industrial applications. In this review, we summarize the role of β-CD and its derivatives in the textile industry. First, we present some general physicochemical characteristics, followed by its application in the areas of dyeing, finishing, and wastewater treatment. The review covers the role of β-CD as an auxiliary agent in dyeing, and as a matrix for dye adsorption until chemical modifications are applied a...
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Interfacial interactions between matrix and reinforcement of composites influences greatly in final properties of the material. Carbon Fibers are characterized for to have low interactions with resins when forming a composite material. In... more
Interfacial interactions between matrix and reinforcement of composites influences greatly in final properties of the material. Carbon Fibers are characterized for to have low interactions with resins when forming a composite material. In the present study, 0.3 wt% of GO/rGO were incorporated in three systems of epoxy resin/carbon fiber as reinforcing fillers, trying to profit the chemical affinity between aromatics structures of GO/rGO and polar interactions with epoxy resin. GO/rGO were characterized by XPS, TGA was performed on carbon fiber, epoxy resins and composites obtained and SEM was utilized to observe composite samples in detail once mechanical tests were conducted. Composites experienced noticeable enhancements by employing Bisphenol Epoxy (BP) cured with methyl cyclohexane-1,2-dicarboxylic anhydride (MCHDA) as matrix and carbon fiber of 300 g/cm2 as reinforcement; Youngs modulus, rupture stress and elongation to fail- ure increased almost twofold compared to non-modifie...