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UPCommons - E-prints UPC Universitat Politècnica de Catalunya (63.328 recursos)
E-prints UPC cobreix dues finalitats: per una banda, és el dipòsit institucional de la UPC que recull els articles de revista, les comunicacions de congrés i els reports de recerca generats en les activitats de recerca del personal docent i investigador de la universitat; per l'altra, és una eina que permet accelerar la producció científica, allotjant versions de documents prèvies a la publicació en una revista o a les actes d’un congrés.

Articles de revista

Mostrando recursos 1 - 20 de 100

1. Inter-laboratory comparisons of hexenuronic acid measurements in kraft eucalyptus pulps using a UV-Vis spectroscopic method - Zhu, Yufan; Zhou, H.F; Chai, X.S; Johannes, Donna; Pope, Richard; Valls Vidal, Cristina; Roncero Vivero, María Blanca
An inter-laboratory comparison of a UV-Vis spectroscopic method (TAPPI T 282 om-13 “Hexeneuronic acid content of chemical pulp”) for hexeneuronic acid measurements was conducted using three eucalyptus kraft pulps. The pulp samples were produced in a laboratory at kappa numbers of approximately 14, 20, and 35. The hexeneuronic acid contents of the three pulps were approximately 55–65 μmol/g, or with a variation of approximately 15%. Five laboratories from four different countries participated in this round-robin study as part of the evaluation of the TAPPI provisional method for upgrading to a TAPPI standard method. The comparative study showed that the orders...

2. The detergency of surfactant mixtures and bentonites on cotton fabric - Carrión Fité, Francisco Javier
The primary aim of this work is to attain improvement of the softness of cotton fabric during the washing process with ecological surfactants. To attain that improvement, sodium bentonite was added to the detergent formulations to produce a softening effect during washing and obtain the so called “soft detergent” effect. Sodium bentonite (a mineral composed mainly of hydrated aluminium silicates) was mixed with the surfactants used in ecological detergents. This product was used with a suitable particle size that, given its large specific surface area, facilitated its deposition on the cotton fabric, producing the desired effect of increasing the softness...

3. Softening effect of bentonite and redeposition of solid impurities on washed cotton fabric - Carrión Fité, Francisco Javier
The aim of this work is to propose a contribution to obtain an improvement in the redeposition of solid impurities on cotton fabric during washing with ecological surfactants and also the enhancement of their smoothness. For that purpose, sodium bentonite was added to the detergent formulations to produce a smoothing effect while washing, to obtain what is known as “softergent”. Thus, smoothing with this product, the necessity of adding softener in the last rinse during washing is eliminated, with the savings of softeners and time and more ecological waste water. This was possible given the excellent compatibility of the bentonite...

4. Correlation analysis between a modified ring method and the FAST system - Carrera Gallissà, Enric; Capdevila Juan, Francisco Javier; Valldeperas Morell, José
The original ring method and some of its modified versions were examined with a view to developing a straightforward, universal alternative for use by the textile industry. For this purpose, a total of 42 specimens of commercial woven fabrics differing in composition, weave type and aerial weight were studied by using the FAST method and a modified version of the ring method developed by the authors. Correlation between the results of the two methods was found to depend largely on (a) fabric formability, (b) bending rigidity, and (c) maximum extraction force and the time needed to reach it. Regression equations relating the...

5. Application of microcapsules in spinning - Marsal Amenós, Félix
A new method has been developed for applying microcapsules in the spinning process, in all yarns made on ring spinning machines, whether short fiber or long fiber. The mircocapsules were placed in the interstices of the yarn, before twisting. This solves the problem of permanence of the effect provided by the active ingredients contained in the mircrocapsule, for functionality and use of textile garments, against repeated washing. The method is technically and industrially feasible. This has been demonstrated by the interest shown by an important manufacturer of spinning machinery. The proposed method is valid for all types of fibers that...

6. Preparation of durable insecticide cotton fabrics through sol-gel treatment with permethrin - Ardanuy Raso, Mònica; Faccini, Mirko; Amantia, David; Aubouy, Laurent; Borja, Guadalupe
This paper presents the development of an industrially viable procedure for the fabrication of durable insecticide textiles based on the sol–gel technique. Permethrin was incorporated on cotton fabrics by a silicon oxide nanocoating applied by conventional padding followed by curing. The effect of the sol–gel process parameters, such as silica solid content and the permethrin/tetraethyl orthosilicate (TEOS) ratio on the insecticide activity and on the textile properties of the resulting fabricswas evaluated. The application of the nanosol coating results in textiles with a high anti-mosquito effect without altering their flexibility and softness.Moreover, this method allows the insecticide content to be...

7. Effectiveness of novel xylanases belonging to different GH families on lignin and hexenuronic acids removal from specialty sisal fibres - Valenzuela Mayorga, Susana Valeria; Valls Vidal, Cristina; Roncero Vivero, María Blanca; Vidal Lluciá, Teresa; Díaz Lucea, Pilar; Pastor Blasco, Francisco Ignacio Javier
Background: The effectiveness of xylanases on lignin removal from pulps differs widely depending on the enzyme family, the type of pulp and the bleaching sequence among other factors. Xylanases can also reduce the presence of undesirable hexenuronic acids in the papermaking fibers. The performance of non-commercial xylanases belonging to families GH10, GH30, GH30-CBM35 and GH11, and of the multicomponent xylanase from Paenibacillus barcinonensis for lignin and hexenuronic acids removal from sisal (Agave sisalana) has been evaluated. Results: Sisal pulps were bleached by an XP sequence, where X denotes the enzyme treatment and P a hydrogen peroxide extraction stage. Kappa number,...

8. Enzymatic strategies to improve removal of hexenuronic acids and lignin from cellulosic fibers - Valls Vidal, Cristina; Vidal Lluciá, Teresa; Roncero Vivero, María Blanca
Different enzymatic strategies were applied to improve lignin and hexenuronic acid (HexA) removal. Three laccases (L) with different redox potentials were applied in combination with 1-hydroxybenzotriazole or methyl syringate to softwood sulfite and hardwood kraft fibers. The enzymes with a high-redox potential from Pycnoporus cinnabarinus and Trametes villosa were found to be the most efficient. The bleaching efficiency was not significantly influenced by the presence or absence of HexA in the different types of lignocellulosic fibers.Subsequently, the lignin or HexA removal in the presence of different mediators was evaluated in eucalyptus fibers with the T. villosa laccase (TvL). Natural mediators...

9. Preparation of durable insecticide cotton fabrics through sol–gel treatment with permethrin - Ardanuy Raso, Mònica; Faccini, Mirko; Amantia, David; Aubouy, Laurent; Borja, Guadalupe
This paper presents the development of an industrially viable procedure for the fabrication of durable insecticide textiles based on the sol–gel technique. Permethrin was incorporated on cotton fabrics by a silicon oxide nanocoating applied by conventional padding followed by curing. The effect of the sol–gel process parameters, such as silica solid content and the permethrin/tetraethyl orthosilicate (TEOS) ratio on the insecticide activity and on the textile properties of the resulting fabricswas evaluated. The application of the nanosol coating results in textiles with a high anti-mosquito effect without altering their flexibility and softness.Moreover, this method allows the insecticide content to be...

10. Plasma surface functionalization and dyeing kinetics of Pan-Pmma copolymers - Labay, Cedric; Canal Barnils, Cristina; Rodríguez Sorigué, M. Cristina; Caballero Manresa, Gabriel; Canal Arias, José Ma
Fiber surface modification with air corona plasma has been studied through dyeing kinetics under isothermal conditions at 30 °C on an acrylic-fiber fabric with a cationic dye (CI Basic Blue 3) analyzing the absorption, desorption and fixing on the surface of molecules having defined cationic character. The initial dyeing rate in the first 60 s indicates an increase of 58.3% in the dyeing rate due to the effect of corona plasma on the acrylic fiber surface. At the end of the dyeing process, the plasma-treated fabrics absorb 24.7% more dye, and the K/S value of the acrylic fabric increases by 8.8%....

11. An enzyme-catalysed bleaching treatment to meet dissolving pulp characteristics for cellulose derivatives applications - Quintana, Elisabet; Valls Vidal, Cristina; Vidal Lluciá, Teresa; Roncero Vivero, María Blanca
Bleached cellulose with good end-properties (_90% ISO brightness and 62% cellulose preservation) was obtained by using a totally chlorine-free biobleaching process (TCF). Unbleached sulphite cellulose was treated with Trametes villosa laccase in combination with violuric acid. This enzymatic stage (L) was followed by a chelating stage (Q) and then by a hydrogen peroxide stage reinforced with pressurized oxygen (Po), resulting to an overall LQPo sequence. The use of violuric acid was dictated by the results of a preliminary study, where the bleaching efficiency of various natural (syringaldehyde and p-coumaric acid) and synthetic mediators (violuric acid and 1-hydroxybenzotriazole) were assessed. The...

12. Abrasive elements and abrasion resistance tests for car seat upholstery - Jerkovic, Ivona; Pallarés, Josep Maria; Ardanuy Raso, Mònica; Capdevila Juan, Francisco Javier
The weight of textile components in automobiles is expected to rise to 35 kg by 2020, and the average lifetime of a vehicle is about 12 years. Car seats are the most important part of the interior decoration, and polyester is the most widely used material in car seat covering. Abrasion resistance tests are used to quantify the duration of car seat upholstery in normal usage, and this is one of the most important requirements. Several testing methods, standards, and car producer specifications have been developed to define the abrasion resistance of specified materials, and pre-tests have been taken to...

13. Relationship between microstructure and properties of false-twist textured and stabilized polylactide. Part 2: physicochemical characterization, accessibility of the amorphous phase and dyeing behavior - Cayuela Marín, Diana; Montero, Lucila; Riva Juan, Ascensión; Prieto Fuentes, María Remedios; Martí, Meritxell; Manich, Albert M.
Polylactide fibers (PLA), textured by false twist at different temperatures (135, 150 and 165º C) and draw ratios (1.30, 1.35 and 1.40) were stabilized by the application of a continuous thermal treatment at 100º C and 50 m/min. The effect of thermal stabilization on the microstructure was determined by physicochemical tests such as iodine sorption or differential solubility. Iodine sorption and differential solubility are closely related to the crystallinity of the samples. Stabilization enhances crystallinity and orientation with the result that differences between the samples are diminished. Color value differences, albeit reduced, in some cases exceed the accepted limits. Color...

14. Laccase-mediated coupling of nonpolar chains for the hydrophobization of lignocellulose - García Ubasart, Jordi; Vidal Lluciá, Teresa; Torres López, Antonio Luis; Rojas, Orlando J.
We investigate the use of laccase enzymes to couple short nonpolar chains containing aromatic groups onto flax fibers and nanofibrillated cellulose (NFC) with different lignin contents. Trametes villosa, Pycnoporus cinnabarinus, and Myceliophthora thermophila were used to facilitate surface coupling and to produce materials with different levels of hydrophobicity. Heat treatment of fiber webs after lacccase-mediated coupling markedly increased the resistance to water absorption. The highest hydrophobization levels of flax fibers was achieved by coupling dodecyl 3,4,5-trihydroxybenzoate (HB-C12), which yielded water contact angles (WCAs) of 80−96 degrees and water absorption times (drop tests) of ca. 73 min. The results from apparent...

15. Biomodification of cellulose flax fibers by a new cellulase - Garcia Ubasart, Jordi; Torres López, Antonio Luis; Vila, Carlos; Pastor, Francisco J.; Vidal Lluciá, Teresa
The potential of the new cellulase Cel9B from Paenibacillus barcinonensis for the modification of cellulose flax fibers was for the first time assessed in this work. Cel9B treatments were found to enhance the development of properties during the refining of fibers, the precise effects depending on the enzyme dose used. Scanning electron micrographs showed the treatments to alter flax fiber surface and cause defibrillation, peeling and fiber wall removal. Zero-span tensile strength was determined to elucidate the changes in intrinsic resistance of cellulose fibers and solubilization of carbohydrates evaluated by HPLC. Low Cel9B doses resulted in improved tensile strength in...

16. Effect of commercial xylanases applied at extreme conditions in a eucalyptus pulp mill - Fillat, Úrsula; Roncero Vivero, María Blanca; Bassa, Alexandre; Sacón, Vera Maria
In this study, we examined the effect of treating eucalyptus pulp with various commercial xylanases to identify the most effective enzyme for use under the industrial bleaching conditions used at the Jacareí mill of the Brazilian firm Fibria, which include a high pH and temperature. Based on the results, the use of two of the nine enzymes studied reduced the kappa number by 1.5 units, increased brightness by 2.5% ISO, and decreased hexenuronic acids (HexA) content by more than 10 μmol/g relative to a control treatment in the absence of enzyme. The most marked changes in brightness were observed on...

17. Laccase for biobleaching of eucalypt kraft pulp by means of a modified industrial bleaching sequence - Moldes, Diego; Vidal Lluciá, Teresa
Biobleaching of kraft pulp is a possible application of laccase, but it has not been described in detail for complete industrial bleaching sequences yet. Therefore, in this work, the biobleaching of Eucalyptus globulus kraft pulp was performed using a modified industrial totally chlorine-free sequence. The modification consisted in the substitution of an enzymatic delignification stage, based on the application of laccase from Trametes villosa, for the first alkaline extraction one. The enzymatic stage was performed with several synthetic and natural mediators, namely 1-hydroxybenzotriazole (HBT), violuric acid (VA), methyl syringate, and syringaldehyde. Several pulp properties were analyzed after each stage of...

18. Effect of residual lignin and heteropolysaccharides in nanofibrillar cellulose and nanopaper from wood fibers - Ferrer Carrera, Ana; Quintana, Elisabet; Filpponen, Ilari; Solala, Iina; Vidal Lluciá, Teresa; Rodríguez Pascual, Alejandro; Laine, Janne; Rojas, Orlando J.
Unbleached (UN), oxygen-delignified and fully-bleached (FB) birch fibers with a residual lignin content of ca. 3, 2 and\1 %, respectively, were used to produce nanofibrillated cellulose (NFC) and nanopaper by using an overpressure device. The tensile index, elongation and elastic modulus of nanopaper were compared and the effect of residual cellwall components accessed. Under similar manufacturing conditions, UN NFC produced nanopaper with a density of 0.99 g/cm3, higher than that from FB NFC (0.7 g/cm3). This translated in much lower air permeability in the case of UN nanopaper (1 and 11 mL/min for UN and FB samples, respectively). Fundamentally, these...

19. Continuous reuse of water and electrolyte from decolorized reactive dyebaths - López Grimau, Víctor; Gutiérrez Bouzán, María Carmen; Valldeperas Morell, José; Crespi Rosell, Martin
In this work, the feasibility of reusing water and salt from reactive dyebaths after electrochemical decolourization was evaluated. Dyeing series of ten reuses with three reactive dyes (Navy Blue Procion H-EXL, Crimson Procion H-EXL and Yellow Procion H-EXL) were carried out (individually and in a trichromie) and color differences and total organic carbon values were measured to study how the successive reuses affect the quality dyeing. The first reuse produced dyeings with low colour differences with respect to a standard dyeing. In the subsequent reuses, colour differences increased until they reached a constant value at the 4th or 5th reuse, following a similar behavior to the organic...

20. Washing wool with surfactants and a non-toxic solvent microemulsion: influence of water hardness - Carrión Fité, Francisco Javier
In this work, detersive power (soil removal) was studied after washing a soiled wool fabric with addition of a non-toxic solvent microemulsion to conventional washing detergent formulations with the aim of improving the performance of the conventional washing. The non-toxic solvent used was dimethyl sulfoxide micro-dispersed with an amphoteric surfactant as emulsifier. The fabric was washed with biodegradable non-ionic surfactants such as an alcohol ethoxylate (AE) with 7 mE.O. and an alkyl polyglucoside with 1.4 glucoside groups (APG). The fabric used was EMPA 107 wool (soiled with standard impurities). The non-ionic surfactants were used separately and in mixture in varying...

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