UPCommons - E-prints UPC Universitat Politècnica de Catalunya
(51.517 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 81
1.
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...
2.
Cyclodextrin functionalization of several cellulosic substrates for prolonged release of antibacterial agents - Cusola Aumedes, Oriol; Tabary, Nicolas; Naceur Belgacem, Mohamed; Bras, Julien
Several cellulosic substrates have been surface-functionalized with cyclomaltoheptaose (b-cyclodextrin, b-CD) using citric acid as a crosslinker agent to obtain new surface-modified materials able to release antiseptic molecules over a prolonged period, in view of their use in medical domain. Three different commercial cellulosic substrates were used, namely: (i) an uncoated paper, (ii) a crepe paper, and (iii) a medical bandage. They were successfully grafted by a crosslinked polymer consisting on b-CD molecules as assessed by scanning electron microscopy and Fourier transform infrared spectroscopy analysis. Several time–temperature kinetic cycles were performed to reach the optimum curing parameters. The grafted and nongrafted...
3.
The PVP/VI copolymer dye transfer inhibition agent during the washing of the polyester fabric - Carrión Fité, Francisco Javier
The objective of this research was to study the effect of the copolymer polyvinylpyrrolidone/vinylimidazole (PVP/VI) for use as a dye transfer inhibitor (DTI) during the washing of dyed polyester fabric, depending on the detergent components. The DTI was used to find its efficiency during repeated washings of polyester fabric dyed with disperse dyes. At the same time, its efficiency was tested fer preventing dye migration to other fabrics, such as polyester, cellulose diacetate, acrylic, polyamide, cotton and wool. The influence of anionic (SDBS) and non-ionic (alkyl ethoxylates with 6 EO-groups) surfactants in different proportions and with zeolite as a builder...
4.
Application of surface enzyme treatments using laccase and a hydrophobic compound to paper-based media - Cusola Aumedes, Oriol; Valls Vidal, Cristina; Vidal Lluciá, Teresa; Roncero Vivero, María Blanca
A new approach for the hydrophobization of finished cellulosic substrates based on a previously reported enzymatic technique is proposed. Commercial finished paper was hydrophobized by using laccase from Trametes villosa in combination with lauryl gallate (LG) as hydrophobic compound. The efficiency of the method was increased by the use of a lignosulfonate as a natural dispersant to improve the surface distribution of LG on the paper, raise its hydrophobicity and help preserve the enzyme activity. No similar threefold effect from a single compound for the improvement of enzymatic treatments was previously reported. The influence of processing conditions including the LG...
5.
Laccase from Pycnoporus cinnabarinus and phenolic compounds: can the efficiency of an enzyme mediator for delignifying kenaf pulp be predicted? - Andreu Terrén, Glòria; Vidal Lluciá, Teresa
In this work, kenaf pulp was delignified by using laccase in combination with various redox mediators and the efficiency of the different laccase–mediator systems assessed in terms of the changes in pulp properties after bleaching. The oxidative ability of the individual mediators used (acetosyringone, syringaldehyde, p-coumaric acid, vanillin and actovanillone) and the laccase–mediator systems was determined by monitoring the oxidation–reduction potential (ORP) during process. The results confirmed the production of phenoxy radicals of variable reactivity and stressed the significant role of lignin structure in the enzymatic process. Although changes in ORP were correlated with the oxidative ability of the mediators,...
6.
Enzymatic grafting of natural phenols to flax fibres: development of antimicrobial properties - Fillat Latorre, Amanda; Gallardo Román, Óscar; Vidal Lluciá, Teresa; Pastor Blasco, Francisco I. Javier; Díaz Lucea, Pilar; Roncero Vivero, María Blanca
Unbleached flax fibres for paper production were treated with laccase from Pycnoporus cinnabarinus and low molecular weight phenols (syringaldehyde – SA, acetosyringone – AS and p-coumaric acid – PCA) to evaluate the potential of this treatment to biomodify high cellulose content fibres. After the enzymatic treatment with the phenols, an increase in kappa number was found, probably due to a covalent binding of the phenoxy radicals on fibres. Grafting was more evident in pulps treated with PCA (an increase of 4 kappa number points with respect to the laccase control was achieved). Paper handsheets from treated pulps showed antimicrobial activity...
7.
Use of cyclic voltammetry as an effective tool for selecting effcient enhancers for oxidative bioprocesses: importance of pH - Aracri, Elisabetta; Tzanov, Tzanko; Vidal Lluciá, Teresa
Seven natural phenols and two synthetic compounds were evaluated by means of cyclic voltammetry as enhancers for the oxidation of the lignin model compound veratryl alcohol (VAl) and a sulfonated lignin (SL). Their electrochemical behaviors and catalytic efficiencies (CEs) against both substrates were assessed as a function of pH. A general increase in CE of the phenols was for the first time observed in the oxidation of VAl at pH 7 and 8. Methyl syringate (MS), syringic acid (SRC), and syringaldehyde (SRD) exhibited the highest CEs against VAl among the studied phenolic compounds despite the reduced stabilities of their phenoxy...
8.
Performance of new and commercial xylanases for ECF and TCF bleaching of eucalyptus kraft pulp - Valls Vidal, Cristina; Gallardo Román, Óscar; Vidal Lluciá, Teresa; Pastor Blasco, Francisco I. Javier; Díaz Lucea, Pilar; Roncero Vivero, María Blanca
Since xylanases can differ widely in their bleaching efficiency, the performance of one new and two commercial xylanases was evaluated in an eucalyptus kraft pulp following XD (X: xylanase; D: chlorine dioxide) and XP (P: hydrogen peroxide) sequences. The new xylanase did not show a significant bleach boosting effect but increased the hexenuronic acid (HexA) removal by 10% after the D stage. The two commercial xylanases behaved in a different way, being one of them (XC) the most effective in increasing delignification (9%) and brightness (3%ISO). Its effectiveness was related to its greater action on releasing the xylan polymer, thus...
9.
Controle da ensimagem na fiaçao - Marsal Amenós, Félix
O autor mostra, por meio de experimentos, novo método para avaliar a eficácia dos produtos no pré-tratamento dos fios
11.
Nuevo método para la aplicación de las microcápsulas en hilatura - Marsal Amenós, Félix; Palet Alsina, Daniel
Se ha puesto a punto un nuevo método que permite aplicar todo tipo de microcápsulas en el proceso de hilatura, tanto de las fibras cortas como de las fibras largas, para todos aquellos hilos fabricados en continuas de hilar de anillos. La colocación de las microcápsulas en los intersticios del hilo, antes de impartirse la torsión, permite resolver el problema de la permanencia del efecto aportado por los principios activos contenidos en la microcápsula, para la funcionalidad y uso de las prendas textiles, frente a los lavados repetidos
12.
Control de los ensimajes en hilatura - Marsal Amenós, Félix
Se propone un método para valorar la eficacia de un ensimaje, aplicado en el proceso de hilatura, de fácil aplicación industrial y bien correlacionado con la calidad del hilo y de los tejidos obtenidos. Método válido para los procesos de hilatura de fibra cortada, independientemente de su longitud de corte y de finura de las fibras
13.
Determinación de Trash y Neps: ventajas tecnológicas para la hilatura - Marsal Amenós, Félix
En este trabajo se aplica el medidor NATI (Neps And Trash Indicator) en la determinación del contenido de neps y de trash en las cintas y mechas de algodón. Este nuevo equipo es también aplicable a otras fibras, distintas del algodón, ya sean naturales, sintéticas o mezclas de fibras entre sí, que contengan neps y trash y a su vez puede utilizarse para otras formas de presentación de la materia textil, como son las flocas. Se han determinado las condiciones óptimas de trabajo del instrumento y el poder de eliminación de neps y trash en diferentes cardas, comparando los valores...
14.
Simulation of bleaching of soda pulp from Hesperaloe funifera by polynomial and neural fuzzy models - Rosal, Antonio; Valls Vidal, Cristina; Roncero Vivero, María Blanca; Rodríguez Pascual, Alejandro
Influence of variables [soda, (0.5 to 3.0%), hydrogen peroxide (1.0 to 10.0%) and time (1 to 5 h)] in the bleaching of soda pulp of Hesperaloe funifera, on the properties of bleached pulps, was studied. Polynomial and neural fuzzy models had reproduced the results of Kappa number, brightness and viscosity of the pulps with errors less than 10 and 15%, respectively. By simulating the bleaching process of pulp H. funifera, with the polynomial and neural fuzzy models, the optimal values of operating variables can be found, so that the properties of bleached pulps differ little from their best values and...
15.
Influence of enzyme and chemical adsorption on the thermal degradation path for eucalyptus pulp - Barneto, A. G.; Valls Vidal, Cristina; Ariza, José; Roncero Vivero, María Blanca
Changes in thermal degradation path of eucalyptus pulp support enzymes (laccase from Trametes villosa) and chemicals (Tris–HCl or tartrate–tartaric buffer) adsorption on cellulose during biobleaching, thereby increasing cellulose amount that degrades at low temperature and decreasing the apparent crystallinity (ApC) of cellulose crystallites. Changes in ApC, which can be assessed by thermogravimetric analysis—but not X-ray diffraction spectroscopy—affect cellulose volatilization; thus, the higher ApC is, the lower is char production and the higher the volatilization temperature. A linear relationship between ApC and the volatilization/charring ratio (V/C) was observed in this work
16.
Obtaining biobleached eucalyptus cellulose fibres by using various enzyme combinations - Valls Vidal, Cristina; Cadena Chamorro, Edith Marleny; Roncero Vivero, María Blanca
Various combinations of laccases, xylanase and cellulase were used to biobleach cellulose fibres from eucalyptus. The Trametes villosa and Myceliophthora thermophila laccases were used in combination with violuric acid (VATvL system) and methyl syringate (MeSMtL system), respectively, as mediator. A dissimilar mode of action of the two systems was found: the VATvL treatment released both hexenuronic acids and lignin, whereas the MeSMtL released lignin alone. Pulp properties were further improved by applying the mediator before the enzyme during treatment. Pulp properties comparable to those provided by industrial TCF sequences were obtained by inserting a xylanase pretreatment before VATvL, but no...
17.
A neural fuzzy model applied to hydrogen peroxide bleaching of non-wood soda pulps - Rosal, Antonio; Valls Vidal, Cristina; Ferrer, Ana; Rodríguez, Alejandro
A neural fuzzy model was used to examine the influence of pulp bleaching variables of empty fruit bunches from oil palm (EFB) and Hesperaloe funifera, such as soda concentration (0.5-3%), hydrogen peroxide concentration (1-10%) and processing time (1-3 h), on Kappa number, brightness and viscosity. The experimental results are reproduced with errors below 10% and 15% for EFB and H. funifera, respectively. Bleaching pulp simulation permits to obtain optimal values of the operating variables, so that the properties of bleached pulps will only slightly differ from their best values, while the lower values of the operating variables will save chemical...
18.
El control reológico de la mecha aumenta la calidad del hilo y la rentabilidad de la hilatura - Marsal Amenós, Félix
Se propone en este trabajo un control sistemático del comportamiento reológico de las mechas, en una instalación de dinamometría de gradiente de alargamiento constante. Es de aplicación para todo tipo de hilatura, tanto de las fibras cortas como de las fibras largas. Las experiencias industriales realizadas ponen de manifiesto que con este control se optimiza el estirado de la continua de hilar, obteniendo hilos más regulares de masa, con una mayor rentabilidad industrial. Este trabajo se aplica a una hilatura de lana peinada que fabrica hilos finos con una elevada exigencia de calidad
20.
Almidón termoplástico celular reforzado con fibras naturales: Una opción biodegradable para el envasado de alimentos - López Gil, Alberto; Belluci, F.S.; Ardanuy Raso, Mònica; Rodríguez-Pérez, Miguel Ángel; Saja, José Antonio de
Los bioplasticos representan un interesante sector en el mundo de los materiales y actualmente son objeto de un profundo estudio tanto desde el punto de vista académico como tecnológico. Ello es debido principalmente a su origen natural y a su caoacidad de biodegradabilidad en condiciones controladas. El almidón es un prototipo de estos materiales y algunas de sus aplicaciones son uno de los temas analizados por nuestro grupo de investigación CellMat. Concretamente nos hemos centrado en las aplicaciones de este polímero como sólido celular y en el campo del envasado de productos alimenticios. Como método de fabricación se ha empleado...
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