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UPCommons - E-prints UPC Universitat Politècnica de Catalunya (68,193 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 109

1. An improved TCF sequence for biobleaching kenaf pulp: influence of the hexenuronic acid content and the use of xylanase - Andreu Terrén, Glòria; Vidal Lluciá, Teresa
Enzymatic delignification with laccase from Trametes villosa used in combination with chemical mediators (acetosyringone, acetovanillone and 1-hydroxybenzotriazole) to improve the totally chlorine-free (TCF) bleaching of kenaf pulp was studied. The best final pulp properties were obtained by using an L-HBT-QPo sequence developed by incorporating a laccase-mediator stage into an industrial bleaching sequence involving chelation and peroxide stages. The new sequence resulted in increased kenaf pulp delignification (90.4%) and brightness (77.2%ISO) relative to a conventional TCF chemical sequence (74.5% delignification and 74.5% brightness). Also, the sequence provided bleached kenaf fibers with high cellulose content (pulp viscosity of 890 g . mL...

2. Gallic acid vehiculized through liposomes or mixed micelles in biofunctional textiles - Marti Gelabert, Meritxell; Martínez Rodríguez, Vanessa; Lis Arias, Manuel José; Valldeperas Morell, José; de la Maza, Alfons; Parra Juez, José Luis; Coderch Negra, Luisa
Liposomes and mixed micelles were used to vehiculize gallic acid, as antioxidant, when applied to different textiles designed to be in contact with the skin as biofunctional textiles. Foulard and bath exhaustion processes were assayed without the use of a binder. Liposomes with the antioxidant encapsulated were applied to cotton, polyamide, polyester, acrylic, and wool, using bath exhaustion and the pad-dry process. Higher absorption was obtained with bath exhaustion than with the pad-dry process for all fabrics. Liposome application to the different textiles showed an adequate substantivity for most fibers. However, the high desorption of most synthetic acrylic and polyester fibers confirmed the preferential application of...

3. Autoclaved cellulose fibre reinforced cement: effects of silica fume - Fernández Carrasco, Lucía; Claramunt Blanes, Josep; Ardanuy Raso, Mònica
With the aim of developing vegetable-fibre cement composites free of portlandite and with short curing process, this study analyses the influence of the curing conditions and the addition of pozzolanic material on the hydration of Portland cement–fibre matrices. Different specimens of cement composites with and without cellulose fibres and with and without silica fume were cured using autoclaving steam and normal curing. The hydration products and the microstructure of the resulting pastes were analysed by means of FTIR and BSE–SEM and the degree of hydration was quantified with Image analysis. The results indicate that the hydration products and the hardness...

4. Effects of needling parameters on some structural and physico-mechanical properties of needle-punched nonwovens - Ventura Casellas, Heura; Ardanuy Raso, Mònica; Capdevila Juan, Francisco Javier; Cano Casas, Francesc; Tornero García, José Antonio
The main objective of this paper is to study the effects of the processing parameters of the needle-punching machine and the interactions between them on some physico-mechanical properties of interest of nonwoven (NW) fabrics. For this purpose, a fractional factorial design has been planned with two levels for each factor: feeding speed, delivery speed, stroke frequency, penetration depth and gap between plates. Sixteen NW fabrics were obtained from polyester fibre and characterized by tensile strength and stiffness for mechanical behaviour and air permeability as physical properties of interest in some technical applications. The results have been subjected to statistical analysis...

5. Structural insights on laccase biografting of ferulic acid onto lignocellulosic fibers - Rencoret, Jorge; Aracri, Elisabetta; Gutíerrez, Ana; Del Rio, Jose C.; Torres López, Antonio Luis; Vidal Lluciá, Teresa; Martínez, Ángel T.
Treatment of high-kappa sisal pulp with Trametes villosa laccase and ferulic acid resulted in strong increases of kappa-number and acid-group content due to biografting of this phenolic acid, as shown by pyrolysis in the presence of tetramethylammonium hydroxide. The coupling linkages were investigated by 2D NMR of the lignin isolated from pulps. The aromatic region of the spectra showed incorporation of the cinnamic molecule, representing similar to 4% of the lignin content, that according to the displacement of its olefinic C-13(beta)-H-1(beta) signal to 117.0/6.40 ppm would be C-4-etherified. The aliphatic region of the spectra showed that ferulic acid also incorporates...

6. Influence of the dye transfer inhibitors for the washing of softened cotton fabric - Carrión Fité, Francisco Javier
In this, work the performance of several dye transfer inhibitors (DTI) copolymers (PVP, PVNO and PVNO with PVP) was tested for use as DTIs in washing softened undyed cotton fabric, in the presence of a direct dye in the washing bath, with and without water hardness. Three direct dyes were tested: red, blue and yellow. The detergent used was composed of an LAS anionic surfactant and a non-ionic fatty alcohol ethoxylate surfactant with 7¿m. OE, both separately and in the different molar proportions anionic with non ionic, at a total concentration of 5¿×¿10-3¿ M, and in the presence of zeolite...

7. Sonochemically processed cationic nanocapsules: Efficient antimicrobials with membrane disturbing capacity - Fernandes, Margarida M.; Francesko, Antonio; Torrent Burgués, Juan; Carrión Fité, Francisco Javier; Macedo Fernandes, Margarida Maria; Tzanov, Tzanko; Heinze, Thomas
Bacterial-mediated diseases are a major healthcare concern worldwide due to the rapid spread of antibiotic-resistant bacteria. One strategy to manage the bacterial infections while avoiding the emergence of resistant strains implies specific targeting and disruption of bacteria membranes. This work evaluates the potential of nanostructured biopolymer derivatives, nanocapsules (NCs), to disrupt the bacteria cell walls and effectively kill planktonic microorganisms. Two biopolymers, chitosan and cellulose, were chemically modified to synthesize derivatives with improved cationic character (thiolated chitosan and aminocellulose) prior to their processing into nanocapsules via a one-step sonochemical process. The interactions of NCs, displaying an average size of around...

8. Effect of texturing on porosity and critical dissolution time of polyamide 6.6 multifilaments - Cayuela Marín, Diana; Maillo Garrido, Josefina; Morales, C; Manich, Albert M.
The anomalous behaviour of polyamide 6.6 fibres textured by false twist to different physico-chemical techniques (as the critical dissolution time, CDT), compared with those obtained in polyester fibres, was attributed to a cracking of the. surface and/or to an increase in fibre porosity. This cracking appears when original fibre is treated at high temperature and it is due to the breakage of the skin/core structure of polyamide 6.6. This cracking has been demonstrated by the determination of drying kinetics in a thermogravimetric test that has been developed for this fibre

9. Preparation and characterization of cellulosic fibre-reinforced polypropylene foams - Ardanuy Raso, Mònica; Sousa Pais Antunes, Marcelo de; Velasco Perero, José Ignacio
The preparation and characterization of cellulosic fibre-reinforced polypropylene composite foams is presented. The cellulose fibres were isolated from a barley straw obtained from local sources. They were compounded with the polymer in the melt state to obtain composites with nominal concentrations of 10 and 20% by weight. After compression-moulding the composite samples were foamed in a high-pressure batch-process employing CO2 as foaming agent. The effects of the fibre loading on the basics characteristics of the foams was investigated

10. 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...

11. 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...

12. 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...

13. 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...

14. 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...

15. 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...

16. 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,...

17. 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...

18. 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...

19. 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%....

20. 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...

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