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UPCommons - E-prints UPC Universitat Politècnica de Catalunya (81,070 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 129

1. Comparative evaluation of the action of two different endoglucanases. Part II: on a biobleached acid sulphite pulp - Quintana, Elisabet; Valls Vidal, Cristina; Vidal Lluciá, Teresa; Roncero Vivero, María Blanca
A TCF sulphite pulp, bleached at the laboratory scale with a laccase–violuric acid system and complemented with a pressurized hydrogen peroxide stage, was treated with two endoglucanases, one obtained from Paenibacillus barcinonensis (B) and the other one produced from Cerrena unicolor (F) to improve cellulose reactivity. The treated pulps were evaluated in terms of brightness, viscosity, a-cellulose, water retention value, fibre morphology, Fock solubility, NMR and carbohydrate composition of pulps and liquors. Results revealed that both endoglucanases improved cellulose reactivity, albeit in a different way; thus, B caused no scissions in the cellulose chain and no significant reduction in fibre...

2. Comparative evaluation of the action of two different endoglucanases. Part I: on a fully bleached, commercial acid sulfite dissolving pulp - Quintana, Elisabet; Valls Vidal, Cristina; Vidal Lluciá, Teresa; Roncero Vivero, María Blanca
A fully bleached commercial acid dissolving pulp was treated with two endoglucanases, one obtained from Paenibacillus barcinonensis (B) and the other one produced from Cerrena unicolor (F) with the intention to improve cellulose reactivity and processability in the viscose process. B cellulose was tested under 120 U/g oven dry pulp (odp) and the F cellulase under two conditions, 12 and 60 U/g odp. In addition, a purification stage, consisting in a cold caustic extraction (CCE) of 9 % w/v NaOH, was applied before or after the enzymatic treatment in order to reduce the amount of hemicellulose and improve the action...

3. Mejora de la permanencia de las microcápsulas sobre los textiles - Marsal Amenós, Félix
La aplicación de las microcápsulas sobre los textiles es un tema ya conocido y que da, en la mayoría de los casos, buenos resultados. El principal problema es la permanencia del efecto que se quiere impartir al tejido frente al uso y a los lavados sucesivos. La fina cutícula de las microcápsulas se rompe y se pierde el producto activo y en los lavados domésticos o industriales se elimina una gran cantidad de cápsulas. En la actualidad los valores de permanencia máxima sobre los textiles están próximos a los cinco lavados. Con el nuevo método expuesto por Feliu Marsal en...

4. Aplicaçao de microesferas para desenvolvimiento de novos acabamentos têxteis - Maestá Bezerra, Fabricio; dos Santos Crocato, Gilson; Valldeperas Morell, José; Lis Arias, Manuel José; Carreras Parera, Núria; Acuña, Victor
A microencapsuldao é uma técnica muito utilizada por diversas indústrias e consiste em prender princípios ativos, aromas, fármacos, cosméticos e outros, em estruturas, que os liberaráo de maneira dosada e prolongada, de acordo com a aplicaçáo. A obtençáo das mlcrocápsulas é feita das mais diversas formas, utilizando matri:zes e princípios ativos que sejam compatíveis tanto fisicamente quanto quimicamente. .A utilizaçao das microcápsulas na área téxtil é vista como um avanço na área de acabamento e possível soluçáo para uma nova integraçáo entre corpo e substrato textil

5. Studying the effects of laccase treatment in a softwood dissolving pulp: cellulose reactivity and crystallinity - Quintana, Elisabet; Valls Vidal, Cristina; Garcia Barneto, Agustín; Vidal Lluciá, Teresa; Ariza, J.; Roncero Vivero, María Blanca
An enzymatic biobleaching sequence (LVAQPO) using a laccase from Trametes villosa in combination with violuric acid (VA) and then followed by a pressurized hydrogen peroxide treatment (PO) was developed and found to give high bleaching properties and meet dissolving pulp requirements: high brightness, low content of hemicellulose, satisfactory pulp reactivity, no significant cellulose degradation manifested by a-cellulose and HPLC, and brightness stability against moist heat ageing. The incorporation of a laccase–mediator system (LMS) to bleach sulphite pulps can be a good alternative to traditional bleaching processes since thermogravimetric analysis (TGA) showed that the laccase treatment prevented the adverse effect of...

6. Sustainable dyeing of denim using indigo dye recovered with polyvinylidene difluoride ultrafiltration membranes - Buscio Olivera, Valentina; Crespi Rosell, Martin; Gutiérrez Bouzán, María Carmen
Indigo is one of the most consumed dyes in the textile sector, as it is widely used for the dyeing of denim clothes. About 15% of indigo used in the dyeing process is discharged to the wastewater treatment plants or sometimes into rivers, in countries where regulations are not strictly applied. In this work, real effluents that contained indigo dye were treated by means of 4 different ultrafiltration membranes. The feasibility to recover the concentrated dye with lab and semi-industrial pilots was also investigated. The studied membranes achieved up to 99% colour removal and 80% chemical oxygen demand (COD) decrease....

7. Reuse of textile wastewater after homogenization–decantation treatment coupled to PVDF ultrafiltration membranes - Buscio Olivera, Valentina; Marín, María José; Crespi Rosell, Martin; Gutiérrez Bouzán, María Carmen
The textile industry is one of the largest consumers of water in the world and its wastewater is a serious problem when it is discharged without the proper treatment. In this work, wastewater generated by textile industry was treated coupling a homogenization–decantation treatment with polyvinylidene difluoride (PVDF) ultrafiltration membranes. Initially, the wastewater was aerated in a homogenization–decantation tank where 17% colour and 10% chemical oxygen demand (COD) were removed. The aerated effluent was treated with an ultrafiltration membrane in order to reuse the permeate in new dyeing processes. Firstly, the ultrafiltration treatment was performed in a laboratory plant. The permeate...

8. A facile and green method to hydrophobize films of cellulose nanofibrils and silica by laccase-mediated coupling of nonpolar colloidal particles - Cusola Aumedes, Oriol; Roncero Vivero, María Blanca; Vidal Lluciá, Teresa; Rojas, Orlando J.
Hydrophobic particles based on dodecyl 3,4,5-trihydroxybenzoate (LG) were coupled onto the surface of cellulose nanofibrils (CNFs) and silica by treatment with a multicomponent colloidal system (MCS) derived from the laccase-mediated reaction of LG in the presence of a sulfonated lignin (SL). Surface modification upon treatment with MCS was monitored insitu and in real time by quartz crystal microgravimetry. The colloidal stability of MCS and its components in water was followed by measuring space- and time-resolved light transmission and back scattering. The sulfonated lignin increased dispersion stability and reduced the characteristic MCS particle size [from approximate to 4 to approximate to...

9. Rapid functionalisation of cellulose-based materials using a mixture containing laccase activated lauryl gallate and sulfonated lignin - Cusola Aumedes, Oriol; Valls Vidal, Cristina; Vidal Lluciá, Teresa; Roncero Vivero, María Blanca
An innovative method has been developed for the surface hydrophobisation of cellulose-based materials by coating it with a functionalised solution (FS), in which sonicated lauryl gallate (LG, dodecyl 3,4,5,-trihydroxybenzoate), sulfonated kraft lignin, and the enzyme laccase play a pivotal role. The rapid treatment with FS increases the hydrophobicity of cellulose sheets considerably. The FS retention on the paper surface was analysed as a function of refining and application of additives. The properties of the functionalised sheets were assessed by the water-drop test (WDT), and the surface free energy (SFE) was determined via contact angle (CA) measurements in a goniophotometer. WDT...

10. Colour change of polyester dyed fabric during washing by ecological surfactants - Carrión Fité, Francisco Javier
Alkyl polyglucosides (APGs) have appeared on the market, offering good levels of biodegradability and ecotoxicity. These nonionic surfactants, obtained from natural substances, are 100% biodegradable and very suitable for washing. They are highly soluble, only slightly sensitive to electrolytes and rarely influenced by water hardness. This paper analyses the behaviour of APG and linear alkyl sulfonate, separately and in mixtures of different proportions, in order to show how dyed polyester fabric changed colour during washing and how dye transfers to white textile items (diacetate, polyamide, cotton, acrylic and wool). Before this process, the polyester was dyed with disperse dyes. Disperse...

11. Influence of special clays as builder in ecological detergents - Carrión Fité, Francisco Javier
The aim of this work is to determine the influence of certain clay micro particles added to detergent formulation to act as builders in removal of impurities (detersive power) during the washing of a standard cotton fabric (EMPA), and also to determine the whiteness of the fabric and its softness after washing. Sepiolite was used separately and together with bentonite, in the forin of micro partides. Bentonite is held to have a softening effect on cotton. A whitener was added to the detergent formulations to compensate for a possible effect of diminished whiteness in the washed fabric. Scanning electron microscope...

12. Cellulosic fiber reinforced cement-based composites: a review of recent research - Ardanuy Raso, Mònica; Claramunt Blanes, Josep; Toledo Filho, Romildo Dias
In the last few years, an increase in interest has been given to the use of cellulose fibers as alternatives for conventional reinforcements in composites. The development of commercially viable environmentally friendly and healthy materials based on natural resources is on the rise. In this sense, cellulosic fibers as reinforcements for cement mortar composites constitute a very interesting option for the construction industry. This paper presents a review of the research done during the last years in the area of the cement-based composites reinforced with cellulose fibers. The fibers used, processing methods, mechanical behaviour and durability are presented. The main...

13. Cellular structure and mechanical properties of starch-based foamed blocks reinforced with natural fibers and produced by microwave heating - López-Gil, Alberto; Silva-Bellucci, Felipe; Velasco, Daniel; Ardanuy Raso, Mònica; Rodríguez-Pérez, Miguel Ángel
The cellular structure and mechanical properties in compression of starch-based foams filled with natural reinforcements, such as grape wastes, cardoon wastes and barley straw fibers, have been studied in this work. The foams were produced by a microwave foaming process in which water is the plasticizer and at the same time the blowing agent. The use of thermoformed sheets as solid precursors for foaming allowed the production of foamed blocks with cells elongated in the expansion direction and with better properties in terms of rigidity and strength than foams produced in previous works by microwave heating of pellets. Moreover, the...

14. Corona plasma modification of polyamide 66 for the design of textile delivery systems for cosmetic therapy - Labay, Cedric Pierre; Canal Arias, José Ma; Navarro Sentanyes, Antonio; Canal Barnils, Cristina
Cosmetic and medical applications of technical textiles are a research expanding field. One of the added values of these new materials would be that they are suitable to contain and release active ingredients in a controlled manner. The influence of the initial state of the surface of polyamide 6.6 (PA66) fibers on the wetting properties of the fibers as well as on the incorporation of caffeine on the fibers and on its release kinetics from the fibers has been investigated. Comparison between industrially-finished PA66 fabrics and laboratory washed fabrics has been done to carry out this study. Furthermore, surface modification...

15. 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 microcapsules 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 microcapsule, 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...

16. Effect of surface treatment of titanium dioxide nanoparticles on non-isothermal crystallization behavior, viscoelastic transitions and cold crystallization of poly(ethylene terephthalate) nanocomposites - Cayuela Marín, Diana; Cot Valle, María Ana; Riva Juan, Mª del Carmen; Sanchez Leija, Regina Janete; Sanchez Loredo, Maria Guadalupe; Algaba Joaquín, Inés María; Manich Bou, Albert M.
The effect of untreated and tri-n-octylphosphine oxide (TOPO) surface-treated TiO2 nanoparticles when included as filler in poly (ethylene terephthalate) on its compatibility, non-isothermal crystallization behavior, viscoelastic transitions and cold crystallization has been studied. The effectiveness of the surface treatment has been studied using infrared spectrophotometry (FTIR) and thermogravimetric analysis (TGA). The effect of the untreated and surface-treated nanofiller content in the polymer, added by an extrusion process, on the non-isothermal crystallization has been studied by differential scanning calorimetry (DSC). The influence on the viscoelastic transitions and cold crystallization of PET nanocomposites has been studied through thermomechanical analysis (TMA). The surface...

17. A critical comparison of methods for the analysis of indigo in dyeing liquors and effluents - Buscio Olivera, Valentina; Crespi Rosell, Martin; Gutiérrez Bouzán, María Carmen
Indigo is one of the most important dyes in the textile industry. The control of the indigo concentration in dyeing liquors and effluents is an important tool to ensure the reproducibility of the dyed fabrics and also to establish the efficiency of the wastewater treatment. In this work, three analytical methods were studied and validated with the aim to select a reliable, fast and automated method for the indigo dye determination. The first method is based on the extraction of the dye, with chloroform, in its oxidized form. The organic solution is measured by Ultraviolet (UV)-visible spectrophotometry at 604 nm....

18. Strategies to improve the mechanical properties of starch-based materials: plasticization and natural fibers reinforcement - López Gil, Alberto; Rodríguez Pérez, Miguel Ángel; de Saja, José Antonio; Bellucci, Felipe Silva; Ardanuy Raso, Mònica
Biodegradable polymers are starting to be introduced as raw materials in the food-packaging market. Nevertheless, their price is very high. Starch, a fully biodegradable and bioderived polymer is a very interesting alternative due to its very low price. However, the use of starch as the polymer matrix for the production of rigid food packaging, such as trays, is limited due to its poor mechanical properties, high hidrophilicity and high density. This work presents two strategies to overcome the poor mechanical properties of starch. First, the plasticization of starch with several amounts of glycerol to produce thermoplastic starch (TPS) and second,...

19. Estudi de la composició de les mostres de teixit dels enterraments de la fossa de la Basílica dels Sants Màrtirs Just i Pastor de Barcelona - Carrera Gallissà, Enric
Postprint (published version)

20. Characterization and treatments of oil palm frond fibers and its suitability for technical applications - Ventura Casellas, Heura; Morón Soler, Moises; Ardanuy Raso, Mònica
The aim of this paper is to explore the potential of oil palm frond fibers (OPFf) for technical applications such as composite reinforcement. For this purpose, fibers obtained from frond wastes were subjected to various chemical treatments with NaOH and chemically and morphologically characterized. Afterward, composites of poly-lactic acid matrix and nonwoven matts made with the treated and the untreated OPFf were prepared and the mechanical properties tested. It was found that the alkaline treatment was effective for increasing the wettability of the fibers leading to composites with a good-balanced between lightness and toughness for potential applications in packaging or...

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