Person: Sánchez Salvador, José Luis
Loading...
First Name
José Luis
Last Name
Sánchez Salvador
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Ingeniería Química y de Materiales
Area
Identifiers
11 results
Search Results
Now showing 1 - 10 of 11
Item In Situ Production and Application of Cellulose Nanofibers to Improve Recycled Paper Production(Molecules, 2019) Balea Martín, Ana; Sánchez Salvador, José Luis; Monte, María de la Concepción; Merayo Cuevas, Noemí; Negro Álvarez, Carlos Manuel; Blanco Suárez, ÁngelesThe recycled paper and board industry needs to improve the quality of their products to meet customer demands. The refining process and strength additives are commonly used to increase mechanical properties. Interfiber bonding can also be improved using cellulose nanofibers (CNF). A circular economy approach in the industrial implementation of CNF can be addressed through the in situ production of CNF using side cellulose streams of the process as raw material, avoiding transportation costs and reducing industrial wastes. Furthermore, CNF fit for use can be produced for specific industrial applications.This study evaluates the feasibility of using two types of recycled fibers, simulating the broke streams of two paper machines producing newsprint and liner for cartonboard, to produce in situ CNF for direct application on the original pulps, old newsprint (ONP), and old corrugated container (OCC), and to reinforce the final products. The CNF were obtained by 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-mediated oxidation and homogenization at 600 bar. Handsheets were prepared with disintegrated recycled pulp and different amounts of CNF using a conventional three-component retention system. Results show that 3 wt.% of CNF produced with 10 mmol of NaClO per gram of dry pulp improve tensile index of ONP ~30%. For OCC, the same treatment and CNF dose increase tensile index above 60%. In both cases, CNF cause a deterioration of drainage, but this effect is effectively counteracted by optimising the retention system.Item Optimization of reagent consumption in TEMPO-mediated oxidation of Eucalyptus cellulose to obtain cellulose nanofibers(Cellulose, 2022) Xu, Hongyu; Sánchez Salvador, José Luis; Balea Martín, Ana; Blanco Suárez, Ángeles; Negro Álvarez, Carlos ManuelEucalyptus cellulose is usually pre-treated by oxidation with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), NaBr and NaClO at pH 10.5 and 25 °C before the mechanical process required to obtain cellulose nanofibers (CNFs). In this study, different aspects to improve the effectiveness and sustainability of the TEMPO-mediated oxidation are analyzed. The optimization was carried out at different reaction times by modifying both the concentration of the NaClO and the amount of the catalysts (TEMPO and NaBr). Results show that the carboxyl groups increased up to 1.1 mmol/g with 5 mmol NaClO/g after 50 min, and that the catalyst concentration can be reduced to 0.025 mmol TEMPO/g and 0.5 mmol NaBr/g to minimize costs while maintaining the high fibrillation degree of the CNFs. The kinetic of the reaction can be considered as zero-order with respect to NaClO, and as first order with respect to cellulose. As a result of this work, the catalyst doses are reduced up to 75% compared to the most widely used catalyst doses (0.1 mmol/g TEMPO and 1 mmol/g NaBr), obtaining highly fibrillated CNFs with a lower environmental impact. This reduction of catalyst doses will reduce the costs and facilitate the implementation of CNF production at industrial scale.Item Comparison Of Mechanical And Chemical Nanocellulose As Additives To Reinforce Recycled Cardboard(Scientific Reports, 2020) Sánchez Salvador, José Luis; Balea Martín, Ana; Monte Lara, M. Concepción; Negro Álvarez, Carlos Manuel; Miller, Meaghan; Olson, James; Blanco Suárez, ÁngelesRecycling cycles cause a decrease in mechanical paper properties due to cellulose fiber degradation. The use of cellulose micro/nanofibers (CMF/CNF) to reinforce paper strength has been well studied, although it has been found to have negative effects on drainage. However, the application of CMF/CNF as paper reinforcement is affected by the nanocellulose type. Thus in this study mechanical and chemical treatments in CNF production were compared. Old corrugated container (OCC) pulp used to produce recycled cartonboard was reinforced with 1) CMF from never-dried northern bleached softwood kraft pulp (NBSK) highly refined in a 16-inch low consistency refiner at 1200 rpm and 25 kW of net power; and 2) CNF from NBSK pulp treated by TEMPO-mediated oxidation and homogenization at 600 bars. CMF/CNF and OCC were pulped at the same time and handsheets formed with cationic starch (CS) as retention system. Mechanical, drainage and flocculation properties were evaluated and compared. Data were also compared with other sources of TEMPO CNF. Results show an improvement in mechanical properties, drainage and flocculation when OCC is reinforced with CMF obtained with LCR. Therefore, high fibrillation was not necessary to improve mechanical paper or cardboard properties.Item Enhanced Morphological Characterization of Cellulose Nano/Microfibers through Image Skeleton Analysis(Nanomaterials, 2021) Sánchez Salvador, José Luis; Campano Tiedra, Cristina; López Expósito, Patricio; Tarrés, Quim; Mutjé, Pere; Delgado Aguilar, Marc; Monte Lara, M. Concepción; Blanco Suárez, ÁngelesThe present paper proposes a novel approach for the morphological characterization of cellulose nano and microfibers suspensions (CMF/CNFs) based on the analysis of eroded CMF/CNF microscopy images. This approach offers a detailed morphological characterization and quantification of the micro and nanofibers networks present in the product, which allows the mode of fibrillation associated to the different CMF/CNF extraction conditions to be discerned. This information is needed to control CMF/CNF quality during industrial production. Five cellulose raw materials, from wood and non-wood sources, were subjected to mechanical, enzymatic, and (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO)-mediated oxidative pre-treatments followed by different homogenization sequences to obtain products of different morphologies. Skeleton analysis of microscopy images provided in-depth morphological information of CMF/CNFs that, complemented with aspect ratio information, estimated from gel point data, allowed the quantification of: (i) fibers peeling after mechanical pretreatment; (ii) fibers shortening induced by enzymes, and (iii) CMF/CNF entanglement from TEMPO-mediated oxidation. Being mostly based on optical microscopy and image analysis, the present method is easy to implement at industrial scale as a tool to monitor and control CMF/CNF quality and homogeneity.Item Simplification of gel point characterization of cellulose nano and microfiber suspensions(Cellulose, 2021) Sánchez Salvador, José Luis; Monte Lara, M. Concepción; Negro Álvarez, Carlos Manuel; Batchelor, Warren; Garnier, Gil; Blanco Suárez, ÁngelesNanocellulose is an emerging material that needs to be well characterized to control its performance during industrial applications. Gel point (Øg) is a convenient parameter commonly used to estimate the aspect ratio (AR) of cellulose nano/microfibers (CNFs/CMFs), providing critical information on the nanofiber network. However, its estimation requires many sedimentation experiments, tedious and time consuming. In this study, a simpler and faster technique is presented to estimate Øg, based on one or two sedimentation experiments, reducing the experiments by a factor of at least 2.5. Here, this new methodology is successfully validated by using the Øg of different CNF/CMF hydrogels calculated with the traditional methodology, showing an error lower than 7%. The error in the estimation of the AR is lower than 3% in all cases. Furthermore, the two mathematical models currently used to estimate Øg, the smoothing spline and the quadratic fit, are compared and the mathematical assumptions improved.Item Critical comparison of the properties of cellulose nanofibers produced from softwood and hardwood through enzymatic, chemical and mechanical processes(International Journal of Biological Macromolecules, 2022) Sánchez Salvador, José Luis; Campano Tiedra, Cristina; Balea Martín, Ana; Tarrés, Quim; Delgado Aguilar, Marc; Mutjé, Pere; Blanco Suárez, Ángeles; Negro Álvarez, Carlos ManuelCurrent knowledge on the properties of different types of cellulose nanofibers (CNFs) is fragmented. Properties variation is very extensive, depending on raw materials, effectiveness of the treatments to extract the cellulose fraction from the lignocellulosic biomass, pretreatments to facilitate cellulose fibrillation and final mechanical process to separate the microfibrils. Literature offers multiple parameters to characterize the CNFs prepared by different routes. However, there is a lack of an extensive guide to compare the CNFs. In this study, we perform a critical comparison of rheological, compositional, and morphological features of CNFs, produced from the most representative types of woody plants, hardwood and softwood, using different types and intensities of pretreatments, including enzymatic, chemical and mechanical ones, and varying the severity of mechanical treatment focusing on the relationship between macroscopic and microscopic parameters. This structured information will be exceedingly useful to select the most appropriate CNF for a certain application based on the most relevant parameters in each case.- Project number: 290
Item Desarrollo y aplicación de una metodología innovadora para realizar visitas técnicas virtuales a empresas y centros de investigación() Blanco Suárez, Ángeles; Balea Martín, Ana; Monte Lara, M. Concepción; Negro Álvarez, Carlos; de la Fuente González, Elena; Hierro Paredes, Eva; Romero De Ávila Hidalgo, María Dolores; Tijero Cruz, Antonio; Plaza Rodriguez, Jesus; Sánchez Salvador, José Luis; Ojembarrena Jiménez, Francisco de Borja; Xu, Hongyu; Gascó Guerrero, Antonio María; Márquez Negro, Alejandro; Hermosilla Redondo, Daphne; Aguado García, Sofía; Alarcón Mondéjar, Juan Ignacio; González Seade, Sofía; Sánchez Calatayud, TaniaEl objetivo del proyecto es desarrollar una metodología innovadora para realizar visitas técnicas virtuales a plantas industriales y/o centros de investigación con alumnos que podrán utilizarse en 8 asignaturas de 4 grados y 2 másteres de la UCM. Item Gel Point as Measurement of Dispersion Degree of Nano-Cellulose Suspensions and Its Application in Papermaking(Nanomaterials, 2022) Sánchez Salvador, José Luis; Balea Martín, Ana; Negro Álvarez, Carlos Manuel; Monte Lara, María Concepción; Blanco Suárez, ÁngelesThe dispersion degree of cellulose micro and nanofibrils (CMFs/CNFs) in water suspensions is key to understand and optimize their effectiveness in several applications. In this study, we proposed a method, based on gel point (Øg), to calculate both aspect ratio and dispersion degree. This methodology was validated through the morphological characterization of CMFs/CNFs by Transmission Electronic Microscopy. The influence of dispersion degree on the reinforcement of recycled cardboard has also been evaluated by stirring CMF/CNF suspensions at different speeds. Results show that as stirring speed increases, Øg decreased to a minimum value, in which the aspect ratio is maximum. Then, Øg increased again. Suspensions with lower Øg, in the intermediate region of agitation present very good dispersion behavior with an open and spongy network structure, in which nanofibril clusters are totally dispersed. Higher stirring speeds shorten the nanofibrils and the networks collapse. Results show that the dispersion of the nanocellulose at the minimum Øg before their addition to the pulp, produces higher mechanical properties, even higher than when CNFs and pulp are agitated together. This method allows for the determination of the CMF/CNF dispersion, to maximize their behavior as strength agents. This knowledge would be crucial to understand why some industrial trials did not give satisfactory results.Item Study of The Reaction Mechanism to Produce Nanocellulose-Graft-Chitosan Polymer(Nanomaterials, 2018) Sánchez Salvador, José Luis; Balea Martín, Ana; Monte Lara, María Concepción; Blanco Suárez, Ángeles; Negro Álvarez, Carlos ManuelCellulose and chitin are the most abundant polymeric materials in nature, capable of replacing conventional synthetic polymers. From them, cellulose nano/microfibers (CNFs/CMFs) and chitosan are obtained. Both polymers have been used separately in graft copolymerization but there are not many studies on the use of cellulose and chitosan together as copolymers and the reaction mechanism is unknown. In this work, the reaction mechanism to produce nano/microcellulose-graft-chitosan polymer has been studied. Recycled cellulose pulp was used, with and without a 2,2,6,6-tetramethylpiperidin-1-oxyl-radical (TEMPO)-mediated oxidation pretreatment, to produce CNFs and CMFs, respectively. For chitosan, a low-molecular weight product dissolved in an acetic acid solution was prepared. Grafted polymers were synthesized using a microwave digester. Results showed that TEMPO-mediated oxidation as the cellulose pretreatment is a key factor to obtain the grafted polymer CNF-g-CH. A reaction mechanism has been proposed where the amino group of chitosan attacks the carboxylic group of oxidized cellulose, since non-oxidized CMFs do not achieve the desired grafting. 13C NMR spectra, elemental analysis and SEM images validated the proposed mechanism. Finally, CNF-g-CH was used as a promising material to remove water-based inks and dyes from wastewater.Item Pickering Emulsions Containing Cellulose Microfibers Produced by Mechanical Treatments as Stabilizer in the Food Industry(Applied Sciences, 2019) Sánchez Salvador, José Luis; Balea Martín, Ana; Monte Lara, M. Concepción; Blanco Suárez, Ángeles; Negro Álvarez, Carlos ManuelPickering emulsions are emulsions stabilized by solid particles, which generally provide a more stable system than traditional surfactants. Among various solid stabilizers, bio-based particles from renewable resources, such as micro- and nanofibrillated cellulose, may open up new opportunities for the future of Pickering emulsions owing to their properties of nanosize, biodegradability, biocompatibility, and renewability. The aim of this research was to obtain oil-in water (O/W) Pickering emulsions using cellulose microfibers (CMF) produced from cotton cellulose linters by mechanical treatment through a high-pressure homogenizer. The O/W Pickering emulsions were prepared with different O/W ratios by mixing edible oil (sunflower oil) with water containing CMF at concentrations of up to 1.0 wt%. The apparent viscosity of the separated emulsion phase was measured. Results showed the feasibility of using low concentration of CMF for preparing and stabilizing Pickering emulsions, with the apparent viscosity of the emulsion phase increasing 60–90 times with respect to the sunflower oil, for a shear rate of 1 s−1 . In addition, theoretical nutrition facts of the emulsions were calculated and compared with other fats used in foods, showing that they can be a promising low-calorie product containing dietary fiber, replacing trans and saturated fats in foods.