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The techno-economic feasibility of lavender essential oil supercritical CO2 extraction was studied. The process was scaled up to a pilot plant, and the extraction yield, composition, and antioxidant potential of the extracts were evaluated at 60 °C and 180 bar or 250 bar, achieving a maximum yield of 6.9% and a percentage inhibition of the extracts of more than 80%. These results drove the development of a business plan for three scenarios corresponding to different extraction volumes (20, 50, and 100 L) and annual production. The SWOT matrix showed that this is a promising business idea. The COM was calculated and an investment analysis was performed. The profitability of this process was demonstrated by means of a financial analysis for 8 years, considering a selling price of 1.38 EUR/g for the extract from the 20 L plant and 0.9 EUR/g for industrial-scale plants, supported by the price curve. The sensitivity analysis showed that the price of the equipment was the factor that could most influence the robustness of the project and the business strategy, and the financial ratios evaluation resulted in a ROE value above 57% in all cases, indicating the economic attractiveness of the process.

[EN] This research develops a novel teleoperation for robot manipulators based on augmented reality. The proposed interface is equipped with full capabilities in order to replace the classical teach pendant of the robot for carrying out teleoperation tasks. The proposed interface is based on an augmented reality headset for projecting computer-generated graphics onto the real environment and a gamepad to interact with the computer-generated graphics and provide robot commands. In order to demonstrate the benefits of the proposed method, several usability tests were conducted using a 6R industrial robot manipulator in order to compare the proposed interface and the conventional teach pendant interface for teleoperation tasks. In particular,the results ofthese usabilitytests show thattheproposedapproach is more intuitive, ergonomic,and easy to use. Furthermore, the comparison results also show that the proposed method clearly improves the velocity of the teleoperation task, regardless of the user's previous experience in robotics and augmented reality technology., This work was supported by the Spanish Government under the project DPI2017-87656-C2-1-R.

OBJECTIVE To determine whether topical applications of thiosulfinate-enriched Allium sativum extract (TASE) can accelerate acute cutaneous wound healing (WH) in a murine model. METHODS Keratinocyte viability and in vitro wound closure were assessed in keratinocyte cultures. Effects of topical TASE (0.5 μg/mL of allicin in 97% ethanol) on acute cutaneous WH were determined in a murine model of acute cutaneous wound. Twelve mice were alternately assigned to the vehicle- and TASE-treated groups (n=6 per group). Expression levels of mRNA for keratinocyte differentiation marker-related proteins (filaggrin, loricrin and involucrin) and lipid synthetic enzymes (elongation of very long chain fatty acids protein 4 (ELOVL4), fatty acid synthase (FA2H), 3-hydroxy- 3-methyl-glutaryl-coenzyme A reductase (HMGCoA), and serine palmitoyltransferase (SPT)) were assessed using real-time quantitative polymerase chain reaction on day 3 and 8 after wounding, while transepidermal water loss (TEWL) rates were measured in wounded areas. RESULTS TASE accelerated WH both in vivo (40% vs. 22% reduction in wound area, P

The copper(I)-catalyzed azide/alkyne cycloaddition is recognized as one of the most successful click reactions to access self-assembling amphiphilic polymer-drug conjugates (PDCs). In this way, poor water-soluble drugs can be linked covalently to hydrophilic poly(ethylene glycol) (PEG) to obtain PEGylated drug micelles that can be used as versatile carriers for the delivery of diverse therapeutic agents. In this work, two novel amphiphilic PDCs that combine PEG with privileged scaffolds well-known for their anticancer properties, such as coumarin and 5-fluorouracil, have been synthesized and characterized. These conjugates were able to self-assemble into micelles at relatively high critical micellar concentration, probably due to the large portion of hydrophilic PEG. The micelles allowed to load other anticancer drugs (paclitaxel, curcumin, and gemcitabine), providing a unique opportunity to develop promising co-delivery carriers for synergistic cancer therapy. The Korsmeyer-Peppas mathematical model was used for describing the in vitro kinetics of drug release from the micelles. Similar sustained and controlled drug release profiles were obtained for paclitaxel and curcumin in both conjugates, which was attributed to the excellent stability driven by the strong interaction between polymeric conjugates and drugs in the micelle core. In contrast, the high instability observed for the gemcitabine-loaded micelles provided an initial uncontrolled burst release of drug. A preliminary in vitro cytotoxicity study of the micelles against human pancreatic cancer cells PANC-1 and BxPC-3 was also carried out, demonstrating that both coumarin and 5-fluorouracil retain their anticancer properties after conjugation with PEG., La cicloadición de azida/alquino catalizada por cobre (I) se reconoce como una de las reacciones de clic más exitosas para acceder a conjugados de polímero-fármaco anfifílicos (PDC) autoensamblados. De esta manera, los fármacos poco solubles en agua se pueden unir covalentemente al poli(etilenglicol) (PEG) hidrofílico para obtener micelas de fármacos PEGilados que se pueden utilizar como vehículos versátiles para la administración de diversos agentes terapéuticos. En este trabajo, dos PDC anfifílicos novedosos que combinan PEG con andamios privilegiados conocidos por sus propiedades anticancerígenas, como la cumarina .y 5-fluorouracilo, han sido sintetizados y caracterizados. Estos conjugados pudieron autoensamblarse en micelas a una concentración micelar crítica relativamente alta, probablemente debido a la gran porción de PEG hidrofílico. Las micelas permitieron cargar otros medicamentos contra el cáncer (paclitaxel, curcumina y gemcitabina), lo que brinda una oportunidad única para desarrollar portadores de administración conjunta prometedores para la terapia sinérgica contra el cáncer. Se utilizó el modelo matemático de Korsmeyer-Peppas para describir la cinética in vitro de la liberación del fármaco desde las micelas. Se obtuvieron perfiles similares de liberación sostenida y controlada del fármaco para paclitaxel.y curcumina en ambos conjugados, lo que se atribuyó a la excelente estabilidad impulsada por la fuerte interacción entre los conjugados poliméricos y los fármacos en el núcleo de la micela. Por el contrario, la alta inestabilidad observada para las micelas cargadas con gemcitabina proporcionó una liberación inicial descontrolada del fármaco. También se llevó a cabo un estudio preliminar de citotoxicidad in vitro de las micelas contra las células de cáncer de páncreas humano PANC-1 y BxPC-3, demostrando que tanto la cumarina como el 5-fluorouracilo conservan sus propiedades anticancerígenas después de la conjugación con PEG.

This article contains data related to the research article entitled "Carbon dioxide sorption and melting behavior of mPEG-alkyne". The presented data gives information on the thermodynamics properties of the solvent and the polymer. The time saturation of mPEG-alkyne in supercritical carbon dioxide (scCO2) was evaluated in a high-pressure variable volume cell in different period of time at different pressure at the same temperature. The effects of pressure and temperature on the density of CO2 when it is above supercritical conditions are determined with Sanchez Lacombe and Bender Equation and compared with the NIST database and values of equation of Bender. The characteristic parameters of CO2 were determined with the equations proposed by Chengyong Wang et al. [1] and the sum of squared error was calculated for each parameter. Furthermore in this work the solubility data of scCO2/polymer mixture were correlated with Sanchez Lacombe Equation of State (SL EOS) and Heuristic model proposed by Irene Pasquali et al. [2]. This work describes the methodology for solving the SL EOS between the polymer and scCO2 and the procedure of determining the solubility parameter with the group contribution method necessary to apply the heuristic model is described., Este artículo contiene datos relacionados con el artículo de investigación titulado "Sorción de dióxido de carbono y comportamiento de fusión de mPEG-alquino". Los datos presentados brindan información sobre las propiedades termodinámicas del solvente y el polímero. El tiempo de saturación de mPEG-alquino en dióxido de carbono supercrítico (scCO 2 ) se evaluó en una celda de volumen variable de alta presión en diferentes períodos de tiempo a diferentes presiones a la misma temperatura. Los efectos de la presión y la temperatura sobre la densidad del CO 2 cuando está por encima de las condiciones supercríticas se determinan con la ecuación de Sánchez Lacombe y Bender y se comparan con la base de datos del NIST y los valores de la ecuación de Bender. Los parámetros característicos del CO 2se determinaron con las ecuaciones propuestas por Chengyong Wang et al. [1] y se calculó la suma del error cuadrático para cada parámetro. Además, en este trabajo se correlacionaron los datos de solubilidad de la mezcla scCO 2 /polímero con la Ecuación de Estado de Sánchez Lacombe (SL EOS) y el modelo heurístico propuesto por Irene Pasquali et al. [2]. Este trabajo describe la metodología para resolver el SL EOS entre el polímero y el scCO 2 y se describe el procedimiento de determinación del parámetro de solubilidad con el método de contribución de grupo necesario para aplicar el modelo heurístico.

A new sustainable green protocol for obtaining polyethylene glycol (PEG) conjugates, with a prototype molecule, which in this work was coumarin, by means of click chemistry is presented. The organic solvents commonly used for this type of reaction were replaced by supercritical carbon dioxide (scCO2). The synthesis and characterization of PEG-coumarin were successfully reported using FTIR, 1H NMR, and MALDI TOF. Subsequently, a preliminary study was carried out using the response surface methodology to examine the variables that most affect the use of scCO2 as a reaction medium. The main effects caused by these variables, individually and their binary interaction, have been estimated. The response surface methodology has been used in this work to screen variables using a factorial design 23. The p-values of temperature and pressure were 0.006 and 0.0117, being therefore the most significant variables of the response surface methodology study. Subsequently, a more intensive study has been carried out on the variables that have shown the greatest significant effect on reaction performance where an 82.32% synthesis success was achieved, which broadens the scope of the use of scCO2 as a reaction medium. The conjugated coumarin with mPEG-alkyne and coumarin were evaluated for their in vitro antioxidant activities by the DPPH radical scavenging assay and were found to exhibit substantial activities. The click product showed comparable or even better efficacy than the initial coumarin., Se presenta un nuevo protocolo verde sostenible para la obtención de conjugados de polietilenglicol (PEG), con una molécula prototipo, que en este trabajo fue la cumarina, mediante química click. Los solventes orgánicos comúnmente utilizados para este tipo de reacción fueron reemplazados por dióxido de carbono supercrítico (scCO 2 ). La síntesis y caracterización de PEG-cumarina se informó con éxito utilizando FTIR, 1 H NMR y MALDI TOF. Posteriormente, se realizó un estudio preliminar utilizando la metodología de superficie de respuesta para examinar las variables que más inciden en el uso de scCO 2como medio de reacción. Se han estimado los principales efectos causados ​​por estas variables, individualmente y su interacción binaria. En este trabajo se ha utilizado la metodología de superficie de respuesta para cribar variables mediante un diseño factorial 2 3 . Los valores de p de temperatura y presión fueron 0,006 y 0,0117, siendo por tanto las variables más significativas de la metodología de superficie de respuesta estudiada. Posteriormente se ha realizado un estudio más intensivo sobre las variables que han mostrado un mayor efecto significativo en el rendimiento de la reacción donde se ha conseguido un 82,32% de éxito de síntesis, lo que amplía el alcance del uso de scCO 2como medio de reacción. La cumarina conjugada con mPEG-alquino y cumarina se evaluó en cuanto a sus actividades antioxidantes in vitro mediante el ensayo de captación de radicales DPPH y se encontró que exhibía actividades sustanciales. El producto clic mostró una eficacia comparable o incluso mejor que la cumarina inicial.

A new sustainable green protocol for obtaining polyethylene glycol (PEG) conjugates, with a prototype molecule, which in this work was coumarin, by means of click chemistry is presented. The organic solvents commonly used for this type of reaction were replaced by supercritical carbon dioxide (scCO2). The synthesis and characterization of PEG-coumarin were successfully reported using FTIR, 1H NMR, and MALDI TOF. Subsequently, a preliminary study was carried out using the response surface methodology to examine the variables that most affect the use of scCO2 as a reaction medium. The main effects caused by these variables, individually and their binary interaction, have been estimated. The response surface methodology has been used in this work to screen variables using a factorial design 23. The p-values of temperature and pressure were 0.006 and 0.0117, being therefore the most significant variables of the response surface methodology study. Subsequently, a more intensive study has been carried out on the variables that have shown the greatest significant effect on reaction performance where an 82.32% synthesis success was achieved, which broadens the scope of the use of scCO2 as a reaction medium. The conjugated coumarin with mPEG-alkyne and coumarin were evaluated for their in vitro antioxidant activities by the DPPH radical scavenging assay and were found to exhibit substantial activities. The click product showed comparable or even better efficacy than the initial coumarin.

In this work, we sought to investigate the effects of a thiosulfinate-enriched garlic extract, co-administered with 5-fluorouracil (5-FU) or oxaliplatin chemotherapy, on the viability of colon cancer cells (Caco-2 and HT-29). We also addressed the economic feasibility of a new combined treatment of this thiosulfinate-enriched garlic extract, with oxaliplatin that could reduce the dosage and costs of a monotherapy. The thiosulfinate-enriched garlic extract not only enhanced the impact of 5-FU and oxaliplatin (500 µM) in decreasing Caco-2 and HT-29 viability, but also showed a higher effect than standard 5-FU and oxaliplatin chemotherapy as anti-cancer agents. These results provided evidences for the combination of lyophilized garlic extract and 5-FU or oxaliplatin as a novel chemotherapy regimen in colon cancer cells that may also reduce the clinical therapy costs., En este trabajo, buscamos investigar los efectos de un extracto de ajo enriquecido con tiosulfinato, coadministrado con quimioterapia con 5-fluorouracilo (5-FU) u oxaliplatino, sobre la viabilidad de las células de cáncer de colon (Caco-2 y HT-29). . También abordamos la viabilidad económica de un nuevo tratamiento combinado de este extracto de ajo enriquecido con tiosulfinato, con oxaliplatino que podría reducir la dosis y los costes de una monoterapia. El extracto de ajo enriquecido con tiosulfinato no solo mejoró el impacto del 5-FU y el oxaliplatino (500 µM) en la disminución de la viabilidad de Caco-2 y HT-29, sino que también mostró un efecto mayor que el 5-FU estándar y la quimioterapia con oxaliplatino como anticancerígeno agentes.

Use of copper wire bits as simple catalyst in a click chemistry reaction using supercritical CO2 has been achieved. The use of this catalyst in the reaction between polylactic acid (PLA) and coumarin allows to remove the whole amount of catalyst in the final product with a simple purification step using a green solvent where no toxic solvent is used in order to synthetize the product., Se ha logrado el uso de brocas de alambre de cobre como catalizador simple en una reacción química clic usando CO2 supercrítico . El uso de este catalizador en la reacción entre el ácido poliláctico (PLA) y la cumarina permite eliminar la cantidad total de catalizador en el producto final con un simple paso de purificación usando un solvente verde donde no se usa ningún solvente tóxico para sintetizar el producto.

[EN] This article develops a human-robot cooperation to carry out treatments such as sanding, polishing, etc. on the surface of a known rigid object. For this purpose, a vision system is considered to get the object location to ensure not only the perpendicularity of the obot tool to the object surface but also a smooth approach of the tool to the surface. In order to add flexibility, the proposal includes the simultaneous combination of automatic and manual modes of operation. Thus, the human user can guide the robot tool to treat arbitrary areas (manual mode) and, when the operator releases the tool, the robot goes into the automatic mode to treat prior established areas. The method uses a task prioritization framework and three types of controllers: an admittance controller for the tool guidance; a hybrid controller to modify the tool orientation and, in the automatic mode, the tool position; and a sliding mode controller to limit the velocity at which the tool approaches the object surface. The applicability and efficacy of the proposed method is demonstrated experimentally using a conventional 6R robot arm., This work was supported in part by the Spanish Government, and in part by the Generalitat Valenciana under Grant DPI2017-87656-C2-1-R and Grant ACIF/2019/007.

Background: Chemical industry has increased the investment into and innovation capacity to supply chemicals from safe and sustainable sources, which will be essential to offering new solutions and supporting the green transition of the global economy and society. In this sense, the use of green solvents and reusable heterogeneous catalysts has emerged as a promising sustainable process strategy for engineering, chemistry and the environment. In this work, different homogeneous (copper bromide, CuBr and copper(II) acetate, Cu (CH3COO)2·H2O) and heterogeneous (Cu Wire, Cu Plate, Cu/β-SiC, pre-treated Cu Wire and pre-treated Cu Plate) copper catalysts were tested for the copper(I)-catalyzed alkyne–azide cycloaddition (CuAAC) reaction. In addition, the influence of different reaction media was analyzed, comparing the use of an organic solvent such as toluene and a green solvent such as supercritical CO2 (scCO2). Methods: Characterization of the catalysts includes by X-ray diffraction (XRD), Scan Electron Microscopy (SEM), Atomic absorption spectrophotometry (AA) and Temperature Programmed Reduction (TPR). Parameters such as catalyst loading, reaction time, reusability and leaching of the catalysts were studied to obtain more information on the CuAAC reaction in scCO2. Results: The pre-treated copper plate achieved a 57% increase in reaction yield compared to the non pre-treated copper plate. However, the recovery and reuse of the pre-treated copper plate showed a severe deterioration and a considerable change in its surface. Cu Wire (without pre-treatment) achieved yields of up to 94.2% after reusing it for five cycles. Conclusions: These results suggest the possibility to exploit the combination of heterogeneous catalysts and scCO2 and justify further research to highlight green solvents and simultaneously address the challenges of reaction, purification and recycling, Antecedentes: La industria química ha aumentado la inversión y la capacidad de innovación para suministrar productos químicos de fuentes seguras y sostenibles, lo que será esencial para ofrecer nuevas soluciones y apoyar la transición ecológica de la economía y la sociedad mundiales. En este sentido, el uso de disolventes verdes y catalizadores heterogéneos reutilizables ha surgido como una estrategia de proceso sostenible prometedora para la ingeniería, la química y el medio ambiente. En este trabajo, diferentes compuestos homogéneos (bromuro de cobre, CuBr y acetato de cobre(II), Cu (CH 3 COO) 2 ·H 2O) y catalizadores de cobre heterogéneos (alambre de Cu, placa de Cu, Cu/β-SiC, alambre de Cu pretratado y placa de Cu pretratado) se probaron para la reacción de cicloadición de alquino-azida catalizada por cobre (I) (CuAAC). Además, se analizó la influencia de diferentes medios de reacción, comparando el uso de un disolvente orgánico como el tolueno y un disolvente verde como el CO 2 supercrítico (scCO 2 ). Métodos: La caracterización de los catalizadores incluye difracción de rayos X (XRD), microscopía electrónica de barrido (SEM), espectrofotometría de absorción atómica (AA) y reducción de temperatura programada (TPR). Se estudiaron parámetros como carga de catalizador, tiempo de reacción, reutilización y lixiviación de los catalizadores para obtener más información sobre la reacción de CuAAC en scCO 2. Resultados: La placa de cobre pretratada logró un aumento del 57 % en el rendimiento de la reacción en comparación con la placa de cobre no pretratada. Sin embargo, la recuperación y reutilización de la placa de cobre pretratada mostró un severo deterioro y un cambio considerable en su superficie. Cu Wire (sin pretratamiento) logró rendimientos de hasta el 94,2 % después de reutilizarlo durante cinco ciclos. Conclusiones: estos resultados sugieren la posibilidad de explotar la combinación de catalizadores heterogéneos y scCO 2 y justifican más investigaciones para resaltar los disolventes verdes y abordar simultáneamente los desafíos de la reacción, la purificación y el reciclaje

For the first time the functionalization via click chemistry of polylactic acid (PLA) with coumarin in supercritical conditions CO 2 has been achieved. Click reaction was performed at atmospheric pressure and supercritical carbon dioxide (scCO 2 ) for comparison being observed that is possible to obtain similar yields, higher than 95% in both cases. Once click functionalization of PLA in scCO 2 was achieved the influence of operational conditions on the polymer characteristics and in the yield was studied to get an optimized functionalization process.

Polymer aerogels reinforced with carbon nanofibers and alumina aerogels reinforced with hydroxyethyl-cellulose have been successfully synthesized by means of a pilot plant freeze-drying process. Their main physicochemical properties have been measured and compared, and their production costs have been computed. The SWOT matrix of the process has been determined from internal and external analyses, revealing the interest of these products as building insulation materials and the need of establishing a detailed economic analysis. A homemade Excel-VBA application was designed in order to determine the economic parameters of the freeze-drying process. As a consequence of the total economic and physicochemical analysis, it was concluded that the production of aerogels reinforced with hydroxyethyl-cellulose could only be recommended if they are used as an insulating material in buildings with higher thermal stability requirements., Se han sintetizado con éxito aerogeles poliméricos reforzados con nanofibras de carbono y aerogeles de alúmina reforzados con hidroxietilcelulosa mediante un proceso de liofilización en planta piloto. Se han medido y comparado sus principales propiedades fisicoquímicas y se han calculado sus costes de producción. La matriz DAFO del proceso se ha determinado a partir de análisis internos y externos, revelando el interés de estos productos como materiales aislantes para la construcción y la necesidad de establecer un análisis económico detallado. Se diseñó una aplicación Excel-VBA casera para determinar los parámetros económicos del proceso de liofilización. Como consecuencia del análisis económico y fisicoquímico total

This work studies the feasibility of supercritical technology for the improvement of the loading and release of curcumin in PLGA. We synthetized the poly (lactic-co-glycolic acid (PLGA) support as a solid block, determining the effect of PLGA molar composition in the range (20:80 to 80:20). A curcumin solubility study selected acetone, methanol and ethanol like more convenient solvents. Curcumin impregnation process was studied at atmospheric and high pressure using scCO2. High-pressure impregnation performances practically doubled bulk results, leading to values up to 86.1% and practically free of solvent in a sponge form. These samples could be commercialized without any further purification step. The release kinetics of the samples constantly delivered more than 90% of curcumin between 9 and 12 days. Compared to other technologies our samples improved significantly the combined loading and release characteristics, indicating that supercritical technology is an interesting alternative for curcumin loading and controlled delivery in medical applications., Este trabajo estudia la viabilidad de la tecnología supercrítica para la mejora de la carga y liberación de curcumina en PLGA. Sintetizamos el soporte de poli (ácido láctico-co-glicólico (PLGA) como un bloque sólido, determinando el efecto de la composición molar de PLGA en el rango (20:80 a 80:20). Un estudio de solubilidad de la curcumina seleccionó acetona, metanol y etanol. como solventes más convenientes El proceso de impregnación de curcumina se estudió a presión atmosférica y alta usando scCO 2. Las prestaciones de impregnación a alta presión prácticamente duplicaron los resultados a granel, llegando a valores de hasta el 86,1% y prácticamente sin disolvente en forma de esponja. Estas muestras podrían comercializarse sin ningún otro paso de purificación. La cinética de liberación de las muestras entregó constantemente más del 90 % de curcumina entre 9 y 12 días. En comparación con otras tecnologías, nuestras muestras mejoraron significativamente las características combinadas de carga y liberación, lo que indica que la tecnología supercrítica es una alternativa interesante para la carga y el suministro controlado de curcumina en aplicaciones médicas.

The recycling of polystyrene wastes by precipitation from limonene solutions using CO2 as antisolvent is an alternative and original environmentally friendly route to recover high quality wastes. The most suitable working conditions to conduct the process are selected based on the accurate knowledge of the phase equilibrium for the ternary mixture. To maximize the recycling of polymeric wastes while the consumption of CO2 and limonene is minimized, high values of pressure (≥100 bar), low values of temperature (≤30°C) and moderated concentrations of polymer (≤0.4 g PS/ml limonene) are required.

The synthesis of organic polymer aerogels reinforced with carbon nanofibers (CNF-reinforced polymer aerogels) using polyvinyl alcohol (PVA) as the polymeric matrix, by means of the freeze-drying method has been carried out. The influence of the CNF content in the polymer aerogel and the use of different solvents on the physical, morphological and mechanical properties of the final aerogel composites have been evaluated. The thermal conductivity and the porosity of CNF-reinforced polymer aerogels increased with the content of CNF. However, the density of the synthesized aerogels decreased when the CNF content was increased up to a value of 87.5 g/L. According to a dynamic mechanical analysis, the incorporation of CNF into the PVA matrix enhanced the mechanical characteristics and the glass transition temperature of the resulting CNF-reinforced polymer aerogels. On the other hand, aerogels synthesized using water as the solvent presented higher densities than those synthesized using acetone, butanol, ethanol or tert -butanol. However, their thermal conductivity values were very similar. Finally, an economic evaluation of the production of these materials using the freeze-drying technique was carried out. It was demonstrated the economic feasibility of the manufacturing process of aerogels proposed. Furthermore, no toxic pollutants were released at temperatures below 180 °C.

An environmentally friendly technology to recycle Polystyrene (PS) wastes from a solution of p-Cymene using CO 2 as antisolvent was proposed. In this process, the study of equilibrium of the ternary mixtures CO 2 /p-Cymene/Polystyrene is crucial, and particularly, the solubility of p-Cymene in CO 2 and the sorption of CO 2 in the solution are the key factors since the recovered polymer should be precipitated while the solvent should be fully solubilized in CO 2 . In this work, the effect of pressure (50–100–150 bar), temperature (25–30–40 °C) and polymer concentration (0.05–0.80 g PS/ml p-Cymene) on the solubility of p-Cymene and CO 2 were studied to determine the most suitable conditions to perform the precipitation of Polystyrene. The experimental data were correlated as a function of density and polymer concentration according to modifications of well-known semi-empirical expressions (Chrastil's equation and Dual-Mode model). The optimum conditions to carry out the precipitation process of Polystyrene were calculated from the application of the fitted parameters obtained from the previous proposal. The most suitable conditions to precipitate Polystyrene from its solution in p-Cymene were reached at high values of density, it means, high pressure, low temperature and moderated concentration.

Foaming of polystyrene by previous dissolution in p-cymene is studied using CO2 to saturate the solution followed by a rapid decompression of samples. Although during the saturation stage the polymer is plasticized and the glass transition temperature is decreased, the main advantage offered by using a solvent is the reduction of the working temperature. The effects of pressure, temperature, and initial concentration of the polymer solutions on cell size, distribution of pores, and cell density of the foams are analyzed for optimization of the foaming process in order to achieve microcellular structures. Optimum conditions were achieved at high values of pressure and concentration and low temperature.

In drug delivery systems, mathematical modeling plays an important role in elucidating the release mechanisms, the potential applications of a determinate system matrix–drug, or the design of new delivery systems. In this work, we have modeled porous biodegradable foams based on polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) impregnated with a hydrophobic drug (indomethacin) through a single-step process using supercritical CO2 as foaming agent. The modeling of indomethacin in vitro release was based on a previous model developed to describe accurately the process of release of a hydrophilic drug and consisting of three simpler and more comprehensible stages: external and internal mass transfer as well polymer degradation. It has been modified considering the low aqueous solubility of indomethacin and the variations in the mechanism produced, consequently improving its physical signification. Finally, the solubility of different drugs impregnated and their response in the release profiles were ev...

The foaming process has been traditionally performed at high temperature because the CO 2 and the polymer should behave as a homogeneous solution. The addition of a solvent could avoid the high working temperature while the homogeneity is ensured. Among the terpene oils, limonene outlines as a good candidate to carry out the dissolution of polystyrene because it respects the green chemistry principle, it is highly soluble in CO 2 and very compatible with the polymer. The sorption of CO 2 is the first step of the foaming process. The presence of the terpene oil enhances the solubility of the gas which is solubilized in the Polystyrene as well as in the limonene. During the foaming process, many parameters can be tuned to customize the foams. In this work, a fractional factorial design of experiment was proposed to determine the effect of pressure, temperature, concentration of the solution, contact time and vent time over the diameter of cells, its standard deviation and the cells density. The proposed foaming process can be simply performed at mild pressure and temperature thanks to the presence of the solvent. The results showed that the most suitable conditions to foam polystyrene from limonene solutions are 90 bar, 30 °C, 0.1 gPS/ml Lim, 240 min contacting and 30 min venting. Finally, the samples were characterized to determine the amount of residual solvent, their glass transition and degradation temperature checking that the foams presented around 5% of solvent traces but did not show any evidence of degradation.

The synthesis of aerogels based on carbon nanofibers (CNF aerogels) by a freeze-drying process has been studied. The influence of the polyvinyl alcohol/carbon nanofibers mass ratio (PVA/CNFs), the type of polymer and the use of functionalized CNFs on the physical properties of the resulting CNF aerogels have been evaluated. The morphology and textural properties of the resulting carbon aerogels were characterised by scanning electron microscopy (SEM) and nitrogen adsorption/desorption techniques. The thermal stability of the synthesized materials under nitrogen and oxygen atmospheres was also evaluated by TGA. Lower amounts of PVA gave rise to CNF aerogels with thicker and more amorphous structure due to CNF aggregation. Furthermore, the surface area and the total pore volume decreased on increasing the PVA/CNF mass ratio. It was found that the nature of the polymer had a marked influence on the morphology of the resulting CNF aerogels. The use of polyvinyl pyrrolidone (PVP) enhanced both the ignition characteristics and thermal stability of the CNF aerogels. Aerogels containing functionalized CNFs showed a high density and a low porosity due to the strong interaction of the latter with the polymer. The CNF aerogels described here could have potential uses as ultralight structural materials, thermal insulators and supercapacitors.

Porous biodegradable polymeric foams loaded with drugs have potential applications in tissue engineering and sustained delivery systems. A single-step process using supercritical CO2 as a foaming a...

Dissolution with terpenic solvents is presented as an alternative and original route to recycle Polystyrene wastes at room temperature. Limonene was the chosen solvent to carry out the dissolution process because it presents high compatibility with Polystyrene besides being natural, non toxic and relatively low cost. The solvent removal is possible thanks to supercritical CO 2 since it provides high solubility of Limonene and complete PS insolubility at moderated pressures and temperature. In order to determine the proper working conditions to conduct the precipitation of the polymer, accurate knowledge of the phase equilibrium for mixtures of carbon dioxide, Limonene and Polystyrene should be known. In this work, the solubility of Limonene in the ternary system CO 2 /Limonene/Polystyrene was determined. The phase equilibrium experiments were conducted in a variable-volume view cell employing the static method. These experiments were carried out in the temperature range of 298.15–313.15 K, at pressures up to 15 MPa and in the concentration range of 0.05–0.80 g PS/ml Limonene. Initially the binary systems were studied by means of equations of state: Peng–Robinson in the case of CO 2 /Limonene and Sanchez–Lacombe in the case of Limonene/PS and CO 2 /PS. Predicted data were collected together with the experimental to check the agreement and to determine the limits of the ternary system formed by CO 2 –Limonene–PS. It is indispensable to determine the behaviour of the ternary system to know completely the fluid phase equilibrium. The results indicate that the solubility of Limonene in the vapour phase is favoured by high pressure and temperature as well as low concentration.

Poly(D,L-lactide-co-glycolide), PLGA, is a biodegradable polyester with high interest in medical industry, espe- cially when zinc (II) 2-ethylhexanoate (ZnOct2) is used as catalyst substitute in polymerization processes as a substitute of the toxic tin (II) 2-ethylhexanoate (SnOct2) together an initiator such as methanol to improve the reaction rate. This article shows the optimization of the bulk copolymerization method by using a factorial design approach on three experimental parameters: temperature (T), molar ratio monomers/catalyst (MC ratio) and molar ratio initiator/catalyst (IC ratio). Their influence on mass conversion (X) and number-average molecular weight (Mn) was also discussed. Also it provides a useful tool to select in a fast way the proper experimental conditions for the obtaining of this polymer as a previous stage in the synthesis and impregnation of biodegradable scaffolds. This analysis revealed that the most relevant variable in the process is the temperature, being desirable to use the high value (160oC) in order to obtain high values of conversion and molecular weight.

Supercritical fluid technology was tested to produce biodegradable porous probes impregnated with an antineoplasic drug that once conformed could be used as scaffolds as an alternative to traditional methods of preparation. The impregnation of 5-fluorouracil, a chemotherapy agent, was carried-out at the same time to the foaming process in a one-shot procedure. The polymer foam probes were based on d , l -lactide and glycolide and prepared varying the operating conditions. The homopolymer poly( d , l -lactide) and the copolymer poly( d , l -lactide-co-glycolide) were used as base materials. The influence of stirring speed and venting rate on the drug loading and the average pore size were evaluated in order to optimize the impregnation process. Venting rate revealed to be the most important factor affecting the probes pore size and their morphology. Slow venting rates should be used to promote small pores in order to retard the drug release from the polymeric matrix. Fast stirring rates improves the impregnation process because favours the contact between supercritical CO 2 and the swelled polymer. The presence of glycolide enhanced the mechanical strength of the foam preventing pore collapse. This fact together with the possibility of regulating the rate of the scaffold degradation and the kinetics of drug release makes the usage of the copolymer more attractive for a further medical application.

The economic feasibility of supercritical processes by a business plan strategy has been investigated using as a model the continuous CO 2 fraction of liquid capsicum oleoresin. First, the SWOT matrix of the process has been determined from internal and external analyses, revealing the interest of the process for industrial application and the necessity of a detailed economic analysis. In a second step, the investment and financial analyses have been determined for two different scenarios related to the location of the plant, i.e. within the facilities of the university on the one hand, or as an enlargement of an existent paprika factory, on the other. In this second scenario the pay-back period for the capital investment is 3.5 years and the margin of safety ratios over the accounting period 2011–2015 varies in the interval 2–3, indicating the healthy situation of the project. Finally, sensitivity analysis extends the robustness of the economic evaluation described in this work by revealing slight differences in payback periods and financial ratios when underestimations of 10% of the fixed capital investment and operating costs and of the 5% interest rate are considered. The presented results conclude the economic feasibility of this supercritical process and extend conventional economic analysis by the use of a business plan strategy.

Interfacial tension (IFT) is a key physicochemical parameter that plays an important role during the foaming process of polymers. The pendant droplet method is a useful technique to determine the IFT, which has been studied at mild working conditions (0–9 MPa, 303.15–313.15 K). In this work, limonene and cymene were used as solvent to prepare polymer dissolutions and observe their influence on the experimental IFT measurements. Also, the effect of CO2 on the glass transition of polystyrene and polystyrene dissolutions was studied in order to select the most suitable temperature to carry out the experiments. The behaviour of the polystyrene dissolution in the presence of CO2 can be considered similar to molten polymer. A controlled foaming of the polystyrene-solvent mixtures can be easily carried out at moderate temperature and pressures by exploiting the advantages that provide the solvent, obtaining completely “dried” PS foams.

The incorporation of CO2 into new processes is one of the most important strategies for gas emissions mitigation that also would help to decrease the Carbon footprint. Recycling of wastes is also considered as a route to prevent greenhouse emissions as well as a source of interesting raw material. The process of recycling of polystyrene (PS) wastes using high-pressure CO2 as antisolvent and blowing agent in order to produce microcellular foams with enhanced properties was proposed, because the process could combine the benefits of both strategies for CO2 mitigation while high value-added materials were achieved. The technical, environmental and economical advantages of the recycling of polystyrene wastes were evaluated in an industrial and pilot-scale plant considering that CO2 could be recirculated during the process in several cycles in order to minimise its consumption while the economical profit is maximised., La incorporación de CO 2 a nuevos procesos es una de las estrategias más importantes para la mitigación de emisiones de gases que además ayudaría a disminuir la huella de Carbono. El reciclaje de residuos también se considera una vía para evitar las emisiones de efecto invernadero, así como una fuente de materia prima interesante. Se propuso el proceso de reciclaje de residuos de poliestireno (PS) usando CO 2 de alta presión como antisolvente y agente de expansión para producir espumas microcelulares con propiedades mejoradas, ya que el proceso podría combinar los beneficios de ambas estrategias para la mitigación de CO 2 mientras que el alto valor -Se lograron materiales agregados. Se evaluaron las ventajas técnicas, ambientales y económicas del reciclaje de residuos de poliestireno en una planta industrial y a escala piloto considerando que el CO 2 podría recircularse durante el proceso en varios ciclos para minimizar su consumo y maximizar el beneficio económico.

The use of oleoresin as natural colorant is widely used in daily food and beverages. However, there is still a lack of information about the solid–liquid extraction process to obtain this oily extract from sweet paprika. The effects of different operating variables, such as extraction technique, temperature, powder-to-solvent ratio and type of solvent on oleoresin extraction, were investigated through experiments and the leaching process was theoretically modeled. The results indicated that although extraction yields are not affected by the extraction technique, ultrasound-assisted extraction reduces the extraction time required to achieve them. Hexane as solvent and 298 K were the conditions to reach higher coloring capacities of the extracted oleoresins and, thus, they were selected to model the process. Calculations report a powder-to-solvent ratio of 1:4.3 to obtain the maximum oleoresin recovery (84 wt %) in one single contact stage. Practical Applications In this work, the results obtained from the detailed study about the effect of operating variables on the oleoresin extraction throw light on this process, enhancing the knowledge of the conventional production process and opening new possibilities to achieve the industrial extraction of sweet paprika. In this context, ultrasound-assisted extraction has been proved to be an efficient technique to obtain similar extraction yields to those from the conventional process, but reducing by a factor of at least 24 the extraction times. Furthermore, the modeled results can serve for further scale-up of paprika companies.

Expanded (EPS)or extruded (XPS) polystyrene are packaging or insulation materials with an increasing range of applications, so the enormous volume of wastes generated makes their recycling an urgent task. The general purpose of PS foams recycling is the recovery of a more compact polymer material with minimal degradation of the original polymer chains. In this way the shrinkage and further solubilisation with terpenic solvents can be one of the most efficient and cheap alternatives for the recycling of PS foams. In this work, molecular weight influence of PS, in the range between monomer (104.1 Da) and high molecular weight polymer (108 Da) has been evaluated, confirming experimentally (192,000–350,000 Da) that is not the most relevant variable unlike other polymer properties (cristallinity or polidispersity). Critical concentration and temperature have been calculated to establish the operation condition limits, and it was confirmed that at room temperature and at experimental maximum solubility, polymer precipitation does not carried out. Finally, PS pellets were applied to commercial samples (extruded and expanded polystyrene) obtaining similar results.