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The synthesis of rigid polyurethane (RPU) foams containing thermoregulatory microcapsules has been carried out under reduced pressure conditions with a new foaming formulation to reduce the final composite densities. These optimized RPU foams were able to overpass the drawbacks exhibited by the previous composites over the studied temperature range, working as insulating and thermal energy storage materials. The change in the formulation allowed to decrease the final foam density and enhance their mechanical strength. The effect of the operating pressure (atmospheric, 800 mbar, and 700 mbar) and microcapsules content (up to 30 wt%) on the physical, mechanical, and thermal PU foam properties was studied. The reduction of the pressure from atmospheric to 800 mbar did not have any effect on the cell size, strut thickness, and compression strength 10% of deformation, the Young modulus being even higher at 800 mbar. Nevertheless, a strong impact on the microstructure and mechanical properties was observed for the foam composites obtained at 700 mbar. A deleterious impact on the RPU foams thermal conductivity was observed when using low-pressure conditions. Thermal analyses showed that a composite able to work as heat accumulator and thermal insulation both at transient and at steady state was achieved.

Copolymers from ethylene oxide (EO) and propylene oxide (PO) functionalized with glycidyl propargyl ether (GPE) are synthesized. The GPE allows further attachment of drugs but its influence on the polymeric micelle formation is unknown. In this work, the influence of the structure of these copolymers on their critical micellar concentration (CMC) in water and in the size and stability of obtained micelles is studied. For this purpose, the presence of GPE, the copolymer type (gradient or block), the EO:PO ratio and the initiator (water or ethanol) are modified. Gradient copolymers can be synthesized in a single step thanks to the different monomers reactivity, simplifying the process and obtaining similar CMC values to the block copolymers. The use of ethanol as initiator decreases the block copolymer CMC and increases the polydispersity. Besides, the presence of the GPE does not impede the micelle formation and has low effect on the copolymer CMCs. Finally, the higher the EO:PO ratio, the higher the CMC and the smaller the size of micelles. Moreover, Z-potential, DLS and HRSEM analyses show that the micelles are stable, spherical, capable to incorporate coumarin (a hydrophobic drug) and with apparent hydrodynamic sizes suitable to be absorbed by target cells., Se sintetizan copolímeros de óxido de etileno (EO) y óxido de propileno (PO) funcionalizados con glicidil propargil éter (GPE). El GPE permite una mayor unión de fármacos pero se desconoce su influencia en la formación de micelas poliméricas. En este trabajo se estudia la influencia de la estructura de estos copolímeros en su concentración micelar crítica (CMC) en agua y en el tamaño y estabilidad de las micelas obtenidas. Para ello se modifica la presencia de GPE, el tipo de copolímero (gradiente o bloque), la relación EO:PO y el iniciador (agua o etanol). Los copolímeros de gradiente se pueden sintetizar en un solo paso gracias a la reactividad de los diferentes monómeros, simplificando el proceso y obteniendo valores de CMC similares a los copolímeros de bloque. El uso de etanol como iniciador disminuye la CMC del copolímero en bloque y aumenta la polidispersidad. Además, la presencia del GPE no impide la formación de micelas y tiene un efecto bajo sobre las CMC del copolímero. Finalmente, cuanto mayor sea la relación EO:PO, mayor será la CMC y menor el tamaño de las micelas. Además,Los análisis de potencial Z , DLS y HRSEM muestran que las micelas son estables, esféricas, capaces de incorporar cumarina (un fármaco hidrofóbico) y con tamaños hidrodinámicos aparentes adecuados para ser absorbidos por las células diana.

Hydrophobic release agents were developed from SiO2-CH3 submicron-sized particles containing hydrophilic and hydrophobic functional groups dispersed into a vegetable oil as support. The SiO2-CH3 submicron-sized particles were synthesized by changing the molar ratio between the precursors Tetraethyl orthosilicate (TEOS) and Methyltriethoxysilane (MTES) from 0.66 to 5 (MTEOS-0.66 to MTEOS-5), being the relative amount of SiO2-CH3 quantified by FTIR technique. Mortar specimens having hydrophobic properties were manufactured using 3 wt% of the above SiO2-CH3 submicron-sized particles. Additionally, the concentration effect was studied by using MTEOS-0.66 within 3–10 wt%. The hydrophobic properties of the mortar specimens were checked by measuring the contact angle within water droplets and surface. The particle size increased with the MTES/TEOS molar ratio and according to the hydrophobic properties, the proper release agent must be synthesized by using MTEOS-2.5 dispersed into the vegetable oil and having a concentration of 3 wt%. This hydrophobic release agent led mortar surfaces with contact angles higher than 145°. Waterproofing and mechanical studies on concrete specimens allowed to conclude that this demoulding agent does not have a high penetration depth but improved the concrete waterproofing properties, without depletion in the compressive strength.

An in situ shape-stabilized phase change material (ssPCM) from polyethylene glycol (PEG) has been produced by sol–gel method. The inorganic matrix was in situ formed from tetraethyl orthosilicate (TEOS), controlling the condensation rate in a second alkaline step using NaOH. ssPCMs having a latent heat up to 113.8 J/g were synthetized using a sol with a molar ratio H2O:EtOH:H2SO4:PEG1000:TEOS of 2:0.34:0.021:0.50:1 and an equivalent ratio NaOH/H2SO4 of 1.15 for promoting the gel step. The presence of high-density hydrogen bonds between silanol groups and the ether oxygen atoms of PEG and the existence of latent heat allowed to confirm that the PEG worked in two ways. It either forms the PEG–SiO2 matrix or adsorbs onto the surface of the previous polymeric matrix, losing or conserving its latent heat, respectively. The addition of NaOH allowed to change the functionality of the silicon matrix which strongly affected the water content, the thermal stability, and the amount of active PEG in the ssPCMs, leading to an optimal neutralization condition when an equivalent ratio NaOH/H2SO4 of 1.15 was used. The obtained ssPCM has an appropriate range of operative temperatures, a high latent heat in the range of common thermoregulating materials, and a proper thermal reliability.

Rigid PU foams are properly recycled by a single-phase glycolysis process employing crude glycerol as transesterification agent. A high pure recovered polyol (71% of purity) was obtained using a mass ratio of PU scraps to crude glycerol of 1 to 1, a reaction temperature of 190 °C and stannous octoate as catalyst in a 1.3 wt% concentration. PU foam composites containing thermoregulating microcapsules constituted by a paraffin core (Rubitherm®RT27) and a polymer shell material (LDPE and EVA) were glycolyzed, allowing to recover the microcapsules components and the polyol separately. This way, both components of the composite are recovered and can be reused in the manufacturing of new products; demonstrating for first time the viability of the chemical recycling of this kind of composites. Besides, the developed process was successfully applied for foams containing different proportions between the hard and soft segments, demonstrating its robustness. Finally, the recovered polyols were successfully employed to replace a raw rigid polyether polyol in the synthesis of new rigid PU foams. The most important physical and mechanical properties (density, maximum compressive strength and Young modulus) were maintained constant for the incorporation up to a 25 wt% of recovered polyol coming from conventional rigid PU foam scraps and up to a 37.5 wt% with the recovered polyol from rigid PU foam containing thermoregulating microcapsules. Regarding the effective thermal conductivity, it remained constant, even with 100 wt% of recovered polyol from PU scraps with thermoregulating microcapsules., Las espumas rígidas de PU se reciclan adecuadamente mediante un proceso de glucólisis de una sola fase que emplea glicerol crudo como agente de transesterificación. Se obtuvo un poliol recuperado de alta pureza (71 % de pureza) usando una relación de masa de desechos de PU a glicerol crudo de 1 a 1, una temperatura de reacción de 190 °C y octoato estannoso como catalizador en una concentración de 1,3 % en peso. Compuestos de espuma de PU que contenían microcápsulas termorreguladoras constituidas por un núcleo de parafina (Rubitherm®RT27) y un material de cubierta de polímero (LDPE y EVA) fueron glicolizados, lo que permitió recuperar los componentes de las microcápsulas y el poliol por separado. De esta forma, ambos componentes del composite se recuperan y pueden reutilizarse en la fabricación de nuevos productos; demostrando por primera vez la viabilidad del reciclaje químico de este tipo de composites. Además, el proceso desarrollado se aplicó con éxito para espumas que contenían diferentes proporciones entre los segmentos duros y blandos, demostrando su robustez. Finalmente, los polioles recuperados se emplearon con éxito para reemplazar un poliol de poliéter rígido crudo en la síntesis de nuevas espumas rígidas de PU. Las propiedades físicas y mecánicas más importantes (densidad, resistencia máxima a la compresión y módulo de Young) se mantuvieron constantes para la incorporación de hasta un 25 % en peso de poliol recuperado procedente de desechos de espuma de PU rígida convencional y hasta un 37,5 % en peso con el poliol recuperado. de espuma rígida de PU que contiene microcápsulas termorreguladoras. En cuanto a la conductividad térmica efectiva, se mantuvo constante, incluso con 100% en peso de poliol recuperado de desechos de PU con microcápsulas termorreguladoras.

The morphology and encapsulation efficiency of thermoregulating microcapsules based on a spreading coefficient theory and polar surface energy component were evaluated. For this purpose the microencapsulation of phase change materials (PCMs) with different copolymer shells and using different suspending agents by the suspension-like polymerization technique has been carried out. Contact angles and interfacial tensions were measured, and results were discussed with respect to the internal structure as well as encapsulation efficiency of the microcapsules. A core/shell structure was expected as the equilibrium morphology, whereas the experimental structure exhibited a matrix morphology. A core-shell structure was favored by increasing the polarity of the polymer and decreasing the solubility between the core and shell. The type and amount of suspending agent do not have a significant influence on the final characteristic of the microcapsules. Shells with various polarities were synthesized from styrene (S), divinylbenzene (DVB) and hexa(methacryloylethylenedioxy)cyclotriphosphazene (PNC-HEMA), and it was found that a core-shell structure was only obtained for microcapsules with a high polar surface energy component.

A novel form-stable phase-change material (PCM) based on facing bricks was developed by incorporating thermoregulating PEG-SiO2, synthetized by sol-gel method and based on polyethylene glycol as phase-change material and silica as stabilizer compound. The PEG-SiO2 in its liquid form (sol) is firstly adsorbed inside the porous brick and lastly stabilized (gel) by controlling its gelation time, obtaining form-stable PCMs with PEG-SiO2 contents within 15–110 wt.%. Kinetic adsorption curves of the sol into bricks having different porosities as well as maximum adsorption capacities were obtained. The effective diffusion coefficients (Deff) were estimated by means of Fick’s second law, it being possible to predict the adsorption of sol PEG-SiO2 by the brick as function of its porosity and the free diffusion coefficient. Finally, form-stable PCMs demonstrated an improvement in their thermal energy storage capacity (up to 338%), these materials being capable of buffering the indoor temperature during an entire operational day

Abstract Thermoregulating microcapsules (MC) with flame-retardant properties were used to produce polyurethane (PU) foams. Thermogravimetric analyses of the microcapsules performed under atmospheric air and nitrogen confirmed that the hexa(methacryloylethylenedioxy) cyclotriphosphazene (PNC-HEMA) monomer raised the amount of residue after exposure to high temperature, proving the formation of a thermally stable char layer. Additionally, the flame-retardant properties of the microcapsules were analyzed by micro-combustion calorimetry (MCC), and the PU foams were tested by both MCC and cone calorimetry. The total heat release and maximum heat release rate were lower for microcapsules containing the flame-retardant PNC-HEMA. The composition of the microcapsules has been proved by MCC and TGA, where the release of the encapsulated phase change material (PCM) occurred at the expected temperature. However, in PU foams, the release of PCM is shifted to higher temperatures. Accordingly, these materials can be considered as an important alternative to commonly used microcapsules containing phase PCMs, where a lower flammability is required for their future application. Graphic abstract

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.

In this work, it is proposed to check the viability of the epoxidation process of grape seed oil under supercritical conditions, select and optimize the ratios of the different reagents and/or additives that take part in it. Different experiments were performed involving oil, hydrogen peroxide, CO2 (as the supercritical fluid), sodium bicarbonate and different phase transfer catalysts (PTC) as enhancers for the performance. Operating conditions were set in 150 bar, 40 °C and 15 h. Subsequently, a statistical study of the influence of each of the reagents on the yield was carried out. Finally, it was possible to reach 8.31 % yield by means of the selection of an optimal PTC. This is the first approach reported to the epoxidation of vegetable oils through the utilization of scCO2 not only as a solvent but also as a reactant, using several PTCs and analyzing its effect and that of epoxy agents and enhancers., En este trabajo se propone comprobar la viabilidad del proceso de epoxidación del aceite de pepita de uva en condiciones supercríticas, seleccionar y optimizar las proporciones de los diferentes reactivos y/o aditivos que intervienen en el mismo. Se realizaron diferentes experimentos con aceite, peróxido de hidrógeno, CO 2 (como fluido supercrítico), bicarbonato de sodio y diferentes catalizadores de transferencia de fase (PTC) como potenciadores del rendimiento. Las condiciones de operación se establecieron en 150 bar, 40 °C y 15 h. Posteriormente se realizó un estudio estadístico de la influencia de cada uno de los reactivos en el rendimiento. Finalmente, se logró alcanzar un rendimiento de 8.31 % mediante la selección de un PTC óptimo. Este es el primer enfoque reportado para la epoxidación de aceites vegetales a través de la utilización de scCO 2no solo como disolvente sino también como reactivo, utilizando varios PTC y analizando su efecto y el de los agentes epoxi y potenciadores.

This paper shows the elimination of arsenic (As) and hydrated silica from natural groundwater (48.63 µg L−1 arsenic, 77.5 mg L−1 hydrated silica, 0.33 mg L−1 phosphate, 5 mg L−1 sulfate, 240 mg L−1 alkalinity, 89.5 mg L−1 hardness, pH 8.44 and 450 µS cm−1 conductivity) by electrocoagulation (EC). The flow plant employed a parallel plates EC reactor in series with a flocculator-settler. Aluminum was used as the sacrificial electrode. Before the electrolysis in the flow plant, a systematic study of the aluminum dose was carried using the EC reactor adapted to a jar test. The influence of the mean linear flow velocity (1.2–4.8 cm s−1) and current density (6–9 mA cm−2) on the removal of As and hydrated silica was addressed. The residual concentration of As and hydrated silica in the flow plant was CAs = 4.2 µg L−1 and Chs = 4.5 mg L−1, respectively, at 9 mA cm−2 and 1.2 cm s−1, which agree well with that obtained in the jar test array. The residual As concentration fulfills the World Health Organization (WHO) recommendation (

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.

Slurries with low viscosity and polystyrene (PS) nanoparticle concentration up to 52 wt.% have been synthesized in one-step process with no waste generation, by suspension polymerization and optimizing the concentration of dispersants (sodium dodecyl sulfate, SDS, and the cosurfactant, CS). The CS was manufactured in situ from tetraethyl orthosilicate (TEOS) and vinyltriethoxysilane (VTES). The incorporation of the CS on the PS polymer was confirmed by FT-IR, EDS, and TGA, observing the functionalization of PS nanoparticles with SiOH. Morphology and particle size of the dispersed solid, together with viscosity and stability of the polystyrene slurries (PSSs), were analyzed, finding an abrupt reduction of the viscosity for PSSs by combining SDS and CS. Addition of SDS and CS (3.0 and 1.5 wt.%, respectively) allowed to produce PSSs with improved stability (ζ = − 48.5 mV after 1 year), low viscosity (20.5 mPa·s at 25 °C), and Newtonian behavior, containing up to 40.0 wt.% of single-spherical PS nanoparticles (< 100 nm).

Microcellular scaffolds were prepared using high pressure fluids. Solutions of biodegradable material Poly (lactic-co-glycolic) acid (PLGA) in a green solvent such as ethyl lactate was used as the scaffold matrix. To carry out polymer foaming from polymer solutions allows the possibility of reducing the working temperature. The effect of the ratio lactide to glycolide of the polymer, the working pressure, the initial concentration of the polymer in the solvent and the depressurization time were the variables studied at a temperature of 25 °C. The morphology of the foams obtained was characterized based on the cell diameter and its standard deviation, indicator of the homogeneity of the scaffolds obtained, as well as the density of cells. In addition, a study was performed on how the glass transition temperature (Tg) of a polymer is modified by the plasticizing effect of CO2 pressure., Los andamios microcelulares se prepararon utilizando fluidos a alta presión. Como matriz de andamiaje se utilizaron soluciones de material biodegradable ácido poli (láctico-co-glicólico) (PLGA) en un disolvente verde como el lactato de etilo. Llevar a cabo la espumación de polímeros a partir de soluciones de polímeros permite la posibilidad de reducir la temperatura de trabajo. El efecto de la relación láctido a glicólido del polímero, la presión de trabajo, la concentración inicial del polímero en el solvente y el tiempo de despresurización fueron las variables estudiadas a una temperatura de 25 °C. La morfología de las espumas obtenidas se caracterizó en base al diámetro de celda y su desviación estándar, indicador de la homogeneidad de los andamios obtenidos, así como la densidad de celdas. Además,2 presiones.

Coumarin is successfully incorporated in poly(ethylene oxide)-poly(propylene oxide) block copolymers functionalized with terminal alkynes, PEO-b-PPO-b-GPE, by click reactions at atmospheric pressure and in CO2 supercritical conditions (scCO2). The presence of glycidyl propargyl ether (GPE), an alkynyl-terminated monomer, in the copolymer chain allows the covalent attachment of the coumarin by click chemistry, obtaining polymer–drug conjugates. First, the most suitable synthesis procedure for the above-mentioned copolymers was established. Then, the click reactions were carried out confirming the coumarin attachment by Fourier transform IR and 1H NMR analyses, achieving good yields in both cases with a coumarin content of about 9.3 wt% and avoiding the use of toxic solvents in the case of scCO2. In addition, thanks to the amphiphilic character of the copolymer due to the presence of hydrophilic (PEO) and hydrophobic (PPO) segments, micelle formation is also possible and was confirmed by dynamic light scattering and high resolution SEM. Finally, coumarin incorporation was achieved by micelle formation using the direct dissolution method in order to compare the polymer–drug system properties. This second route allows a drug entrapment efficiency of 14 wt% to be reached. In both cases, the size of the polymeric micelles obtained is in a suitable range to enable permeability. However, an interesting point is the reduction in the size of the micelles with increase in the GPE percentage and with the covalent attachment of the coumarin to the copolymer, which is supposed to improve their permeability. © 2019 Society of Chemical Industry, La cumarina se incorpora con éxito en copolímeros en bloque de poli(óxido de etileno)-poli(óxido de propileno) funcionalizados con alquinos terminales, PEO- b -PPO- b -GPE, mediante reacciones clic a presión atmosférica y en condiciones supercríticas de CO 2 (scCO 2 ). La presencia de glicidil propargil éter (GPE), un monómero terminado en alquinilo, en la cadena del copolímero permite la unión covalente de la cumarina por química clic, obteniendo conjugados polímero-fármaco. En primer lugar, se estableció el procedimiento de síntesis más adecuado para los copolímeros mencionados anteriormente. Luego, se llevaron a cabo las reacciones de clic confirmando la unión de la cumarina por transformada de Fourier IR y 1Análisis de RMN H, consiguiendo buenos rendimientos en ambos casos con un contenido en cumarina del orden del 9,3 wt% y evitando el uso de disolventes tóxicos en el caso del scCO 2. Además, gracias al carácter anfifílico del copolímero debido a la presencia de segmentos hidrofílicos (PEO) e hidrofóbicos (PPO), también es posible la formación de micelas y se confirmó mediante dispersión de luz dinámica y SEM de alta resolución. Finalmente, la incorporación de cumarina se logró mediante la formación de micelas utilizando el método de disolución directa para comparar las propiedades del sistema polímero-fármaco. Esta segunda ruta permite alcanzar una eficacia de atrapamiento del fármaco del 14% en peso. En ambos casos, el tamaño de las micelas poliméricas obtenidas está en un rango adecuado para permitir la permeabilidad. Sin embargo, un punto interesante es la reducción del tamaño de las micelas con el aumento del porcentaje de GPE y con la unión covalente de la cumarina al copolímero, lo que se supone mejora su permeabilidad. © 2019 Sociedad de la Industria Química

A new three step process has been developed and optimized in order to demonstrate that is possible to get complete conversion of free fatty acids (FFA) into estolide esters (biolubricant), biodiesel and choline carboxylates (biosurfactants). This new approach consists in the utilization of HClO4, a cheap and industrially available strong acid, to generate the estolides followed by an esterification process with methanol in presence of a cheap ionic liquid to transform them into estolide esters and the unreacted FFA into biodiesel. A final neutralization step with choline hydroxide allowed to obtain biosurfactants. Finally, estolide esters and biodiesel were optimally split by means of molecular distillation. Both products were found to have excellent properties, fulfilling the requirements of international standards SAE J306 and EN 14214 for lubricants and biodiesel, respectively and demonstrating the industrial application of FFA as raw material to produce higher added value products.

Flexible polyurethane foams (FPUs) having polystyrene (PS) stabilized by silica gel or polystyrene-acrylonitrile (SAN) particles were synthesized employing polymer polyether polyols (PPPs). The filler and its content effect on physical, mechanical and thermal properties of FPUs were studied. The FPU thermal stability increased with PS content into PPP and no interaction filler-polymeric network was observed. Meanwhile, FPUs containing PS as filler were more thermally stable and mechanically resistant -except the elongation-than those from the commercial PPP containing SAN. Contrary to porosity and cell size, the density and hardness are function of the filler type and increase with the filler content although the hardness is practically constant from 10 wt%. Closed cell foams instead of tight foams were produced from filler contents higher than 15 wt%. Synthesized FPUs presented better hardness and density properties but worse mechanical properties than the commercial one. Finally, mechanical properties were similar than FPUs containing inorganic fillers.

This review addresses the removal of fluoride contained in different natural groundwater samples from various parts of the world using the electrocoagulation (EC) process. A detailed analysis of different metals (Fe, Al) and Al alloys used as sacrificial electrodes is carried out. The best performance in removing high concentrations of fluoride from natural groundwater (2–10 mg L−1), until fulfilling the World Health Organization (WHO) recommendation (

Rigid polyurethane (RPU) foams have been successfully glycolyzed by using diethylene glycol (DEG) and crude glycerol (CG) as transesterification agents. However, DEG did not allow to achieve a split-phase process, obtaining a product with low polyol purity (61.7 wt %). On contrary, CG allowed to achieve a split-phase glycolysis improving the recovered polyol purity (76.5%). This is an important novelty since, up to now, RPUs were glycolyzed in single-phase processes giving products of low polyol concentration, which reduced the further applications. Moreover, the nanosilica used as filler of the glycolyzed foams was recovered completely pure. The recovered polyol successfully replaced up to 60% of the raw polyol in the synthesis of RPU foams and including the recovered nanosilica in the same concentration than in glycolyzed foam. Thus, the feasibility of the chemical recycling of this type of polyurethane composites has been demonstrated. Additionally, PU foams were synthesized employing fresh nanosilica to evaluate whether the recovered nanosilica has any influence on the RPU foam properties. These foams were characterized structurally, mechanically and thermally with the aim of proving that they met the specifications of commercial foams. Finally, the feasibility of recovering the of CG by vacuum distillation has been demonstrated.

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.

Rigid polyurethane foams with up to 50 wt% of microcapsules from LDPE-EVA containing Rubitherm®RT27 were synthesized. The influence of microcapsules on the foams density, microstructure and mechanical resistance was studied. Cell size and strut and wall thicknesses were analyzed by SEM. The relationships between densities and foam microstructures with their Young's moduli and collapse stress were found by the Gibson and Ashby formulations and the Kerner equation for mechanical properties of composites. It was found a cell structure change from polyhedral closed-cells to spherical or amorphous open-cells. A good agreement between the experimental and theoretical data was observed but requiring a cell form factor. Thus, Fitting parameters confirmed the high trend of these microcapsules to be incorporated into the foam cell walls and the form factors depicted the abrupt change of cell morphology. Thus, these equations are suitable for predicting the mechanical properties of foams containing fillers of low mechanical resistance.

A simple and rapid reverse-phase high-performance liquid chromatographic method for the simultaneous separation and determination of erlotinib, an antineoplastic agent, which is used in the therapy of advanced or metastatic pancreatic or non-small cell lung cancer, and its metabolites has been developed. This method has been applied to urine and serum samples of patients under erlotinib treatment. After a dilution step, erlotinib and its metabolites have been separated on an Ultrabase 120 A C18 column (4.6 mm i.d. × 150 mm, 5 μm) using methanol: 20 mM phosphate buffer pH 5.0 (60:40; v:v) as mobile phase at a flow rate of 1.4 mL min−1 and detected at 248 nm with a diode array detector. The limits of detection were between 2.1 and 5.1 ng mL−1. Within- and between-day accuracy and precision of the validated method were below the acceptable limits of 15% relative standard deviation at all concentrations tested. The quantitation method was successfully applied for the simultaneous determination of erlotinib and its metabolites in urine and serum samples from patients under clinical treatment of non-small cell lung cancer. The concentration ranges of erlotinib and desmethyl erlotinib in serum were 380–6510 and 66–558 ng mL−1, respectively, in patients under treatment. The objective is to propose a fast and simple method for a direct and reliable quantification of erlotinib and its metabolites in human urine and serum without previous sample treatment steps. The direct injection of diluted urine and serum can be highlighted as the greatest advantage that can be achieved by this method.

Due to the increasing amount of polyurethane waste, chemical recycling of these materials is a topic of growing interest for many researchers. The primary purpose of polyurethane feedstock recycling is to recover the starting polyol. In this study glycerolysis using glycerine from two sources and two purity grades is proposed as a method of chemical recycling. The main effort of this paper focuses on the employment of commercial glycerine of analytical grade and waste glycerine without purification derived from the biodiesel production, as a decomposing agent for polyurethane recycling. In this study, the influence of polyurethane to glycerine mass ratio (PU/GL) and the type of decomposing agent on the chemical structure by FTIR, 1H NMR and GPC was examined. FTIR analysis of the glycerolysates showed absorption peaks similar to the virgin polyol. Those results are in compliance with GPC chromatograms, which showed for all samples, well-defined peak at ca. 13 min of retention time. The molecular weight of glycerolysates was ranging from 800 to 1300 g mol−1 depending on PU/GL mass ratio. The novel decomposition agent, namely waste glycerine derived from biodiesel production was successfully used in glycerolysis process.

The synthesis of polyols from renewable resources, primarily unsaturated vegetable oils, is increasing in importance in the polyurethane market. In this work, previously epoxidized grape seed oil was transformed into an azide-functionalized bio-polyol through a ring–opening reaction with sodium azide. The effectiveness of the ring–opening reaction was confirmed by analysing the depletion of the oxirane group content in the bulk mixture and by Fourier transform infrared spectroscopy (FT-IR). A pseudo-first-order model was proposed for predicting the evolution of epoxide groups, and a good fit was obtained. The dependence of the kinetic rate constant on temperature was evaluated using the Arrhenius equation, and an activation energy value of 0.341 J/mol was obtained. A rigid polyurethane foam was synthesized from an azidified bio-polyol. No structural differences were observed between this foam and a commercial one, but a considerable improvement in thermal stability was observed.

More than 20 wt.% of grape production typically becomes waste during wine production. Grape seed oil can be extracted from this winery by-product through pressing or solvent extraction. This oil constitutes an economic alternative for valuation of by-products obtained from wine manufacturing in the Spanish region of Castilla-La Mancha. Furthermore, epoxidised vegetable oils have become one of the main intermediates for synthesizing different biomaterials. The most extended method for epoxidation is using peracids generated in situ , and many studies have investigated the influence of different variables such us reaction temperature and time, type and amount of catalyst, etc. However, a complete kinetic model able to predict reaction by-products has not yet been developed. In this work, the in situ epoxidation of grape seed oil (iodine value of 141.52 g I 2 /100 g) with aqueous hydrogen peroxide and acetic acid in presence of an acid catalyst was performed, with optimal reaction conditions of 90 °C and 60 min. Also, a general epoxidation reaction mechanism has been proposed. We propose a kinetic model able to predict the formation or depletion of different species in the process. The dependence of kinetic rate constants on temperature was evaluated through the Arrhenius equation. The activation energy for the epoxidation reaction of grape seed oil was 7.30 kcal/mol. The obtained results, particularly the proposed kinetic model, will play an important role in developing a safer and more sustainable epoxidation process, minimizing energy consumption and facilitating scale-up.

n the last years, high resilience polyurethane foams (HR foams) production has experienced an intensive growth as a consequence of their wide application field, causing an important increment of the generated waste. HR foams containing PU dispersions polyols are the last tendency in the HR foam industry, due to the improvement of the flame retardant properties and the emissions reduction of volatile compounds in comparison to the traditional graft polymeric HR polyols. In this work the extension of the glycolysis process to the recycling of this kind of foams has been carried out. Diethylene glycol (DEG), glycerol 99% PS and crude glycerol, coming from the biodiesel production, have been assayed as glycolysis agents. All of these glycolysis agents provided a split phase product with an upper phase mainly constituted by a traditional HR polyol and a bottom phase consisting of the excess of glycolysis agent and several reaction byproducts. However, the polyol content in the final product has been greater with the employment of glycerol. Moreover, flexible and rigid foams have been synthesized by using the recycled polyols or the glycolysis bottom phase, respectively. This way, it is achieved a global and sustainable recycling process for the valorization of two waste substances: the HR PU foam and the crude glycerol., En los últimos años, la producción de espumas de poliuretano de alta resiliencia (espumas HR) ha experimentado un intenso crecimiento como consecuencia de su amplio campo de aplicación, provocando un importante incremento de los residuos generados. Las espumas HR que contienen polioles de dispersión de PU son la última tendencia en la industria de las espumas HR, debido a la mejora de las propiedades ignífugas y la reducción de las emisiones de compuestos volátiles en comparación con los tradicionales polioles HR de injerto. En este trabajo se ha llevado a cabo la extensión del proceso de glicólisis al reciclado de este tipo de espumas. Se han ensayado como agentes de glicólisis el dietilenglicol (DEG), el glicerol 99% PS y el glicerol crudo, procedente de la producción de biodiesel. Todos estos agentes de glicólisis proporcionaron un producto de fase dividida con una fase superior constituida principalmente por un poliol HR tradicional y una fase inferior formada por el exceso de agente de glicólisis y varios subproductos de la reacción. Sin embargo, el contenido de poliol en el producto final ha sido mayor con el empleo de glicerol. Además, se han sintetizado espumas flexibles y rígidas utilizando los polioles reciclados o la fase de fondo de glicólisis, respectivamente. De esta forma, se consigue un proceso de reciclaje global y sostenible para la valorización de dos sustancias residuales: la espuma de PU HR y el glicerol crudo.

Currently, the PU industry is developing new products with enhanced physical, mechanical and structural properties. One of the specialties that is attracting more and more attention from managers and enterprises all over the world are the PUs based on polymer polyether polyols (graft polyols). In this work, the synthesis of graft polyols was developed employing a non-aqueous dispersant (NAD) based on silica gel, which contains in its chemical structure segments with a great affinity for the solid polymeric particles and other segment having a strong affinity for the hydroxyl groups of the liquid polyol. The combination of both polar and non-polar characteristics ensures the stability of the resulting polymer dispersion and prevent the sedimentation and the coalescence of the polymer particles. By using this NAD it was possible to synthesize trifunctional polymer polyether polyol (PPP) from Styrene and containing up to 38.69 wt% of solids. The optimal reaction conditions have been stablished using a concentration of 1.5 wt% NAD, 4 wt% of initiator respect to the monomer amount and a polymerization temperature of 80 °C. The viscosity of the optimal PPP (1930 mPa·s) and the particle size (dv0.5 of 5.427 μm and dn0.5 of 1.711 μm) were in the range of graft polyols available in the market for similar solids content, with the additional advantage of employing a lower quantity of NAD and a softer reaction temperature than those employed in the industrial process (110 °C).

The potential of utilizing geopolymer concrete (GPC) walls containing microencapsulated phase change material (MPCM) in buildings at different environmental conditions has been investigated. The effect of climate conditions (temperature, solar radiation) and MPCM design (shell thickness, concentration) on the energy efficiency of buildings was systematically analyzed based on numerical calculations utilizing the finite differences method with an energy balance approach. The energy efficiency of buildings was found to increase at higher levels of MPCM addition and for thicker concrete walls. When the outdoor temperature is higher than the indoor temperature, increasing the maximum solar radiation causes a higher power consumption, a lower power reduction, and accordingly a reduced energy efficiency of the buildings. Utilizing a PCM with a melting temperature close to the average outdoor and indoor temperatures has a positive effect on enhancing the energy efficiency of buildings. Numerical calculations were used to evaluate the efficiency of using GPC containing two different types of MPCM (PS-DVB/RT27 with a paraffin Rubitherm®RT27 core and a shell of polystyrene cross-linked with divinylbenzene and MF/PCM24 with a paraffin mixture core and a melamine–formaldehyde polymer shell) at the environmental conditions of Oslo and Madrid throughout one year. It was found that a significant reduction of the annual power consumption for heating/cooling can be achieved in both Oslo and Madrid. It was also found that the wall orientation and the season have significant effects on the power consumption and power reductions. The GPC containing MPCM was found to exhibit better performance in Madrid than in Oslo. The developed model can be used as a quantitative tool to design MPCM-concrete walls in different climates.

Aminophosphonated polyols with flame retardant properties are synthesized by ring opening polymerization using diethyl-N,N-bis(2-hydroxyethyl) aminomethyl phosphonate (Fyrol-6) as initiator. The influence of the catalyst type and its concentration on the polymerization rate are studied. The catalyst system formed by potassium methoxide (MeOK) in DMSO as a solvent presents the highest polymerization rate and allows reducing the polydispersity. The thermal resistance of the synthesized polyols is confirmed by the char residues formation. Finally, PU foams are synthesized containing up to a 50 pph of PFyCs[1:1], preserving good cellular structure up to a 25 pph content and improving the fire resistance by increasing the char residue from 7.79 to 22.13 wt % and decreasing the PHRR and the smoke production according to TGA and cone calorimeter tests, respectively, Los polioles aminofosfonados con propiedades ignífugas se sintetizan mediante polimerización con apertura de anillo utilizando dietil-N,N-bis(2-hidroxietil)aminometilfosfonato (Fyrol-6) como iniciador. Se estudia la influencia del tipo de catalizador y su concentración en la velocidad de polimerización. El sistema catalizador formado por metóxido de potasio (MeOK) en DMSO como solvente presenta la mayor tasa de polimerización y permite reducir la polidispersidad. La resistencia térmica de los polioles sintetizados se confirma por la formación de residuos de carbón. Finalmente, se sintetizan espumas de PU que contienen hasta 50 pph de PFyCs[1:1], conservan una buena estructura celular hasta un contenido de 25 pph y mejoran la resistencia al fuego al aumentar el residuo carbonizado de 7,79 a 22,13 % en peso y disminuir el PHRR y la producción de humo según TGA y pruebas de calorímetro de cono, respectivamente

The use of supercritical fluids technology, in particular the use of CO2, is an important advantage over other production techniques of controlled release systems. The impregnation and foaming process can be carried out in a single step. By adjusting the conditions of pressure, temperature, depressurization time or type of polymer used, microcellular scaffolds can be obtained with desired characteristics and adapted to the patient's requirements. Moreover, it has been demonstrated that the use of polymeric solutions allows carrying out impregnation process at mild conditions. In this work, Gemcitabine impregnation in PLGA foams from polymeric solutions of ethyl lactate has been studied. The effect of polymer lactide to glycolide ratio (50:50 or 75:25), pressure (120 or 200 bar) and temperature (25 or 40 °C) were studied for three initial drug ratios (175, 105 or 35 mg GEM/g PLGA). Cell size of the foams varied between 35 μm and 158 μm, achieving an impregnation efficiency higher than 90 %. Finally, a study of the release profile of Gemcitabine in Phosphate Buffered Saline (PBS) was investigated and a mathematical modelling was carried out. In this model it was considered that the release process was divided into three different steps controlled by the external diffusion in the first place, by the internal transfer of mass in the second and then by the degradation of the polymer., El uso de la tecnología de fluidos supercríticos, en particular el uso de CO2, es una importante ventaja frente a otras técnicas de producción de sistemas de liberación controlada. El proceso de impregnación y espumado se puede realizar en un solo paso. Ajustando las condiciones de presión, temperatura, tiempo de despresurización o tipo de polímero utilizado, se pueden obtener andamios microcelulares con las características deseadas y adaptados a los requerimientos del paciente. Además, se ha demostrado que el uso de soluciones poliméricas permite llevar a cabo el proceso de impregnación en condiciones suaves. En este trabajo se ha estudiado la impregnación de gemcitabina en espumas de PLGA a partir de soluciones poliméricas de lactato de etilo. El efecto de la relación entre la lactida y el glicólido del polímero (50:50 o 75:25), Se estudiaron la presión (120 o 200 bar) y la temperatura (25 o 40 °C) para tres proporciones iniciales de fármaco (175, 105 o 35 mg GEM/g PLGA). El tamaño de celda de las espumas varió entre 35 μm y 158 μm, logrando una eficiencia de impregnación superior al 90 %. Finalmente, se investigó un estudio del perfil de liberación de gemcitabina en solución salina tamponada con fosfato (PBS) y se llevó a cabo un modelo matemático. En este modelo se consideró que el proceso de liberación se dividía en tres pasos diferentes controlados por la difusión externa en primer lugar, por la transferencia interna de masa en el segundo y luego por la degradación del polímero. Se investigó un estudio del perfil de liberación de gemcitabina en solución salina tamponada con fosfato (PBS) y se llevó a cabo un modelo matemático. En este modelo se consideró que el proceso de liberación se dividía en tres pasos diferentes controlados por la difusión externa en primer lugar, por la transferencia interna de masa en el segundo y luego por la degradación del polímero. Se investigó un estudio del perfil de liberación de gemcitabina en solución salina tamponada con fosfato (PBS) y se llevó a cabo un modelo matemático. En este modelo se consideró que el proceso de liberación se dividía en tres pasos diferentes controlados por la difusión externa en primer lugar, por la transferencia interna de masa en el segundo y luego por la degradación del polímero.

The reduction of the heat loss by incorporating microcapsules into rigid polyurethane (RPU) foams was studied. This way, composite foams containing between 0% and 50% by weight of microcapsules were synthesized. Microcapsules named as mSD-(LDPE·EVA-RT27) from low density polyethylene (LDPE) and ethylvinylacetate (EVA) copolymer containing Rubitherm®RT27 paraffin wax manufactured in a semi-industrial plant of spray drying were used. TES capacities of these composites were quantified by micro and macro scale, observing that phase change materials (PCMs) inside the foam were not entirely melted. Microcapsules addition promoted an increase of the incoming heat flux but lower heat losses respect to the foam without microcapsules in the transient state. Besides, the thermal conductivity of the composites increased with the content of microcapsules but this increase was also related to the non entirely melted PCM. A mathematical model was proposed in order to quantify the total amount of PCM melted during the test and it was possible to confirm that a higher temperature of 36 °C is required to reach the total melting of the PCM. It was also found that an amount of 40 wt% of microcapsules is the proper quantity to produce thermoregulating foams which combine the two advantages: energy accumulation and insulation during the transient state. Besides, the latent heat of this composite was higher than those reported in literature for thermoregulating RPU foams using MicroPCMs from melamine–formaldehyde or styrene–divinylbenzene (DVB) copolymer containing n-tetradecane or n-octadecane, respectively. Finally, if these materials are implemented in building envelopes the amount of CO 2 emitted to the atmosphere could be reduced as well as saving energy.

A synthetic strategy has been developed to create tailor-made poly(ethylene glycol) and poly(propylene glycol) copolymers functionalized with alkynyl groups that are introduced into the co-polymer chains by the addition of glycidyl propargyl ether (GPE) as co-monomer. The alkynyl-decorated copolymer obtained is used as a starter material to synthesize a drug–copolymer conjugate by copper catalyzed azide-alkyne cycloaddition (CuAAC) reaction (click reaction). This way, hydrophobic drugs can be transformed into water-soluble compounds by improving its absorbability and bioavailability by joining them to tailor-made PEG–PPG–GPE copolymers with low polydispersity and precise molecular weight. In this work, zidovudine (AZT) drug with an azide group was chosen to be attached to the polyether chain. The chemical structure of the copolymer was characterized using infrared spectroscopy, nuclear magnetic resonance, matrix-assisted laser desorption/ionization time of flight mass spectrometry and gel permeation chromatography. Finally, 1 H NMR spectrum confirms the successful addition of the zidovudine drug to the synthesized copolymer by the click reaction.

Microcellular foams are well-known polymeric materials since they present excellent properties: high impact strength, high toughness, high stiffness-to-weight ratio, high fatigue life as well as low dielectric constant and low thermal conductivity. Environment-friendly techniques are being proposed to prepare polymeric foams. In particular, supercritical CO2 (scCO2) has received great attention instead of traditional blowing agents (chlorofluorocarbon hydrochlorofluorocarbons or hydrocarbons) due to its low cost and mild impact on the environment. In the foaming process proposed in this work, mild working conditions (90 bar and 30 °C) were required thanks to the presence of CO2 and p-cymene, which benefits the nucleation and cell growth. The influence of inorganic particles (silica and montmorillonite) on the cell morphology was studied experimentally and theoretically in order to promote the simultaneous formation of the embryos, thereby reducing the average cell size and narrowing the cell size distribution. A great enhancement of the polystyrene foam homogeneity was observed, independent of the nucleating agent employed and under low temperature conditions.

Microcapsules containing di(2-ethylhexyl)phosphoric acid (DEHPA) within a sulfonated poly(styrene-co-divinylbenzene) shell (SMC-DEHPA), were characterized by different analytical techniques including the stepwise isothermal analysis and FT-IR, which indicated the presence of DEHPA, sulfonic groups, and sulfone cross-linking in the material. The separation of copper from aqueous solutions was investigated by equilibrium studies. According to the ideal mass action law model, the useful capacity of this material was 1.782 ± 0.013 equiv kg–1, where DEHPA represents half of this value (in agreement with its content). On the other hand, nonsulfonated microcapsules or those without DEHPA presented lower useful capacities. Furthermore, sulfonated material exhibited an enhancement of the selectivity for copper, as confirmed by the equilibrium constants (Ksulfonated > 104Knonsulfonated). Thus, the incorporation of sulfonic groups into the polymeric shell favors the mobility of the counterions in the microcapsule, m...

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.

Glycolysis is the most widely used recycling process for PU. It consists of a transesterification reaction, in which the ester group joined to the carbolinic carbon of the urethane is interchanged by the hydroxyl group of a glycol. With a large molar glycol excess condition, the reaction product splits in two phases, where the upper layer is mainly formed by the recovered polyol, with a higher purity than in the case of single phase glycolysis processes, and the bottom layer by the excess of glycolysis agent and reaction by-products. However, this huge molar excess causes an important increasing of the operation costs what makes almost impossible the implantation of industrial glycolysis plants. In this work, for the first time in literature, the feasibility of the glycolysis process of flexible PU foam scraps by means of using crude glycerol, a waste of the biodiesel production, as a novel, sustainable and economical (approximately 0.13 $/kg) transesterification agent has been demonstrated, reducing approximately in ten times the operation costs associated to the transesterification agent. Besides, crude glycerol has provided a glycolysis upper phase with a lower content of byproducts and transesterification agent than in the case of using the best transesterification agent described until this moment (DEG), as a consequence of its higher dielectric constant. Furthermore, as a result of the crude glycerol higher dielectric constant, the net yield in polyol of the glycolysis process increases due to the almost negligible presence of polyol in the bottom phase. Furthermore, once the washing of the glycolysis phases has been done, the glycolysis upper phase can be used to replace up to 25 parts per hundred (pph) of a raw flexible polyether polyol in the synthesis of new flexible PU foams. Besides, the glycolysis bottom phase can be valorized recycling it in the formulation of new PU insulating foam replacing partially the raw rigid polyether polyol. Hence, a global, sustainable and economical viable glycolysis process has been achieved by means of using two waste substances (flexible PU foam scraps and crude glycerol), obtaining valuable products of both glycolysis phases.

A new class of particulate material for the selective removal of mercury from polluted aqueous streams has been developed. The material consists in core–shell microcapsules containing a highly selective extractant agent for mercury. For this purpose, trioctylmethylammonium chloride (TOMAC) has been encapsulated within a poly(styrene-co-divinylbenzene) – P(St-DVB) – shell by suspension-like polymerisation technique. This process gave rise to a high product yield with an encapsulation efficiency of 95%. Microcapsules presented an average particle size lower than 40 μm and a TOMAC content of 37.70 wt.%. Different equilibrium experiments for mercury uptake were conducted at pH = 1 and natural pH, using synthetic solutions and natural waters from the mining district of Almaden (Spain). A mathematical model that takes into account the dissociation of mercuric chloride in solution was proposed and the solid equilibrium parameters were obtained. A good fitting between the experimental data and the model was achieved, obtaining a maximum useful capacity of 1.009 ± 0.018 eq kg−1 with a value of equilibrium constant of the monovalent specie ( HgCl 3 - ) two orders of magnitude smaller than those of the divalent HgCl 4 2 - . The mercury uptake was favoured at acid pH and low chloride concentration. Finally, it was demonstrated that using this material is possible to remove more than 92% and 99% of the metal content from the natural waters containing mercury in ng L−1 levels at natural and acid pH, respectively. The use of this new type of extractive microcapsules allows to get mercury removal levels in surface polluted waters that satisfy the mercury standard for aquatic life proposed by the USEPA (12 ng L−1) without additional pretreatments for the adjustment of the pH value.

Poly (lactic-co-glycolic acid) (PLGA) is a copolymer used as drug carrier in controlled release systems as microparticles or scaffolds. Foamed structures are industrially obtained by injecting gas at temperatures above the melting point of the polymer that may promote PLGA degradation. High temperatures are avoidable in this foaming process if a polymer dissolution is used. Ethyl acetate and ethyl lactate are suitable solvents for the PLGA since the polymer is easily solubilised, is environmentally friendly and highly recommendable for medical purposes. CO2 is proposed as antisolvent because is environmentally benign, non-flammable and non-toxic. The knowledge of the solubility of these solvents in CO2 is essential to find the most appropriate working conditions for the foaming process. In this work, the solubility of ethyl acetate and ethyl lactate in CO2 in the presence of different initial concentrations of PLGA has been studied at 298.15 K and at pressures up to 150 bar using a high-pressure variable volume view cell., El poli (ácido láctico-co-glicólico) (PLGA) es un copolímero que se utiliza como transportador de fármacos en sistemas de liberación controlada como micropartículas o andamios. Las estructuras espumadas se obtienen industrialmente mediante la inyección de gas a temperaturas superiores al punto de fusión del polímero que pueden promover la degradación del PLGA. Las altas temperaturas se pueden evitar en este proceso de formación de espuma si se utiliza una disolución de polímero. El acetato de etilo y el lactato de etilo son disolventes adecuados para el PLGA ya que el polímero se solubiliza fácilmente, es respetuoso con el medio ambiente y muy recomendable para fines médicos. El CO2 se propone como antidisolvente porque es ambientalmente benigno, no inflamable y no tóxico. El conocimiento de la solubilidad de estos disolventes en CO 2es fundamental encontrar las condiciones de trabajo más adecuadas para el proceso de espumado. En este trabajo se ha estudiado la solubilidad del acetato de etilo y lactato de etilo en CO 2 en presencia de diferentes concentraciones iniciales de PLGA a 298,15 K y presiones de hasta 150 bar utilizando una celda de visión de volumen variable de alta presión.

Geopolymer concrete (GPC) containing microencapsulated phase change materials (MPCM) were fabricated in order to achieve a high thermal energy storage capacity of an environmental friendly concrete. Different kinds of MPCM were utilized to investigate the influence of the hygroscopic nature, latent heat, and size of microcapsules on the microstructure and thermal properties of GPC. A combination of polar functional groups on the polymer shell and microcapsules with a small size was found to improve the interface bonds between microcapsules and the GPC matrix, how well the MPCM is dispersed in the GPC, and the thermal insulation properties of the GPC. The energy storage capacity of GPC increases at higher concentrations of MPCM and with a higher latent heat of the MPCM. To determine the thermal impact of buildings utilizing GPC containing MPCM, a numerical model was utilized. The model is based on the implicit finite differences method using an energy balance approach and the heat capacity method. In order to improve the model, a new equation was successfully utilized to fit the specific heat capacity of GPC containing MPCM as function of temperature. The numerical model was verified by experimental measurements of the thermal performance of the GPC. The simulated numerical values obtained for GPC containing MPCM were in good agreement with the experimental data. Higher amounts of MPCM and thicker concrete walls reduce the power consumption needed to maintain an indoor temperature of 23 °C. A power reduction of nearly 35% was achieved when utilizing a 75 mm concrete wall containing 5.2 wt.% MPCM. These building materials are therefore promising for improving human comfort and for reducing the energy consumption of buildings.

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.

Mercury is one of the most toxic pollutants, with high capacity of accumulation in living organism, causing important human health problems. Therefore, the mercury removal from water is an important research goal. In a previous work, an extractant agent [di(2-ethylhexyl)phosphoric acid] was microencapsulated in poly(styrene-co-divinylbenzene) by means of suspension polymerisation using toluene as diluent. In this study, this recipe has been modified changing the toluene by heptane and extended to four additional extractants (trioctylamine, trioctylmethylammonium chloride [TOMAC], tributyl phosphate and trioctylphosphine oxide). The polluting potential of the waste liquid from the process was measured by total organic carbon and chemical oxygen demand analyses. The morphology, particle size and distribution were studied by scanning electron microscopy and low angle laser light scattering. The amount of extractant agent into the microcapsules and the microencapsulation efficiency were determined by thermogravimetric analysis and the mercury removal capacity by equilibrium studies. Microcapsules containing TOMAC demonstrated to be the best material for the mercury removal and retention.

A strategy for synthesis and functionalization of polyurethanes (PUs) is described. Polyols bearing terminal groups were prepared by anionic ring-opening copolymerization between propylene oxide and epoxy dimethylphosphonate (POPh). The direct insertion of POPh improves the flammability of PUs. Therefore the structure, properties and flame retardant properties of polyether polyols and PUs were studied. The structure of the polyether polyols was confirmed by gel permeation chromatography (GPC), nuclear magnetic resonance spectroscopy (NMR) and matrix assisted laser desorption ionization time-of-flight (MALDI-TOF). The thermal stability was determined by TGA (thermogravimetric analysis). The morphological structure was analysed by scanning electron microscope (SEM). The elemental composition of the charred residues was determined by energy dispersive x-ray spectrometer (EDAX). The introduction of POPh presents the advantage of being able to increase the percentage of phosphorus introduced in the polyol, which slightly modifies the thermal stability of the phosphorylated foams. The temperature decreased as the phosphorus was incorporated and the percentage of char increased as well. © 2015 Society of Chemical Industry

The objective of this study was to evaluate the feasibility of supercritical oil extraction from Jatropha curcas L (JCL). The influence of the operating conditions on oil yield, free fatty acid content of JCL oil, and oil quality was examined, which included pressure, temperature, particle size, and percentage of hull. The conditions for the fractionation of fatty acid were selected to obtain good-quality oil for biodiesel production. Finally, an experiment was conducted under different conditions in which the greatest amount of free fatty acids (FFA) (26.3 wt.%) was extracted during the first fractions and then the pressure was increased to achieve good oil removal (91 wt.% oil yield) performance with low content of free fatty acids (1 wt.%). This study has a promising role to fill as a more cost-effective processing technology, and it is not necessary to carry out a degumming, esterification and dehydration in the oil of the last fractions. Furthermore, all the phorbol ester was removed from the oil by conducting a supercritical extraction using CO 2 .

Nowadays polymer recycling processes are an urgent task due to the huge quantity of wastes that are generated. Polyurethane is the 6th polymer most used all over the world with a production of approximately 12 million tons per year. Flexible foams represent about the half of polyurethane total production and among them conventional polyurethane flexible foams mean the 80%. This type of foams are synthesized or using only a flexible polyether polyol or a mix of a flexible polyether polyol with a polymeric polyol. A series of works about the glycolysis of flexible foams synthesized only with flexible polyether polyol have been carried out by our research group. In this work, for the first time in literature, a detailed study of the glycolysis of flexible polyurethane foams containing polymeric polyol has been accomplished. It has been demonstrated that is possible to carry out the glycolysis of these foams using similar reactions conditions determined for the glycolysis of conventional flexible polyurethane foams synthesized only with flexible polyether polyol. Furthermore, after a proper treatment process of the recovered polyol, flexible polyurethane foams have been synthesized using mixtures of raw polyol with the recovered one.

Renewable resources are playing a key role on the synthesis of biodegradable polyols. Moreover, the incorporation of covalently linked additives is increasing in importance in the polyurethane (PU) market. In this work, previously epoxidized grape seed oil and methyl oleate were transformed into phosphorylated biopolyols through an acid-catalyzed ring-opening hydrolysis in the presence of H3PO4. The formation of phosphate polyesters was confirmed by FT-IR and 31P-NMR. However, the synthesis of a high-quality PU rigid foam was not possible using exclusively these polyols attending to their low hydroxyl value. In that way, different rigid PU foams were prepared from the phosphorylated biopolyols and the commercial polyol Alcupol R4520. It was observed that phosphorylated biopolyols can be incorporated up to a 57 wt.% in the PU synthesis without significant structural changes with respect to the commercial foam. Finally, thermogravimetric and EDAX analyses revealed an improvement of thermal stability by the formation of a protective phosphorocarbonaceous char layer.

The optimisation process for the synthesis of microcapsules containing trioctylmethylammonium chloride (TOMAC), a selective extractant agent for the removal of mercury from wastewaters, by the suspension copolymerisation of styrene (St) and divinylbenzene (DVB) was studied. The influence of the diluent, mass ratio of the suspending agents (arabic gum –AG– and polivinylalcohol –PVA–), TOMAC:diluent volume ratio and weight percentage of DVB respect to the monomers mixture (% DVB) on the encapsulation process and the physical properties of the resulting microcapsules were investigated. It was found that using heptane as diluent led to non-spherical microcapsules with poor reaction yield and conversion of the monomers. Nevertheless, when toluene was used these properties were improved. Furthermore, for a TOMAC:toluene ratio of 1:3 spherical beads were obtained. The combined use of the suspending agents was more appropriate than using them separately, due to the latex product and the low conversion of the monomers for AG and PVA, respectively. The increase of the % DVB from 18.8 to 50% enhanced the mechanical resistance of the polymeric shell, increasing the reaction yield up to an 84.7% and maintaining the TOMAC encapsulation (36.0%) and the sphericity of the microcapsules. The obtained particle size (40 μm) indicated that the main application of this material will be in fluidised beds or in perfectly mixed reactors. On the basis of the experimental results, a AG:PVA mass ratio of 1:1, a TOMAC:toluene volume ratio of 1:3 and 50% DVB were established as the best conditions to produce this kind of microcapsules, enabling its reproduction on a pilot scale plant. In addition, the high values of the distribution coefficient for mercury removal confirm the success of this optimisation process., Se estudió el proceso de optimización para la síntesis de microcápsulas que contienen cloruro de trioctilmetilamonio (TOMAC), un agente extractante selectivo para la eliminación de mercurio de aguas residuales, mediante la copolimerización en suspensión de estireno (St) y divinilbenceno (DVB). La influencia del diluyente, relación másica de los agentes de suspensión (goma arábiga –AG– y alcohol polivinílico –PVA–), relación volumétrica TOMAC:diluyente y porcentaje en peso de DVB respecto a la mezcla de monómeros (% DVB) sobre el proceso de encapsulación y el Se investigaron las propiedades físicas de las microcápsulas resultantes. Se encontró que el uso de heptano como diluyente conducía a microcápsulas no esféricas con un bajo rendimiento de reacción y conversión de los monómeros. Sin embargo, cuando se utilizó tolueno se mejoraron estas propiedades. Además, para una relación TOMAC:tolueno de 1:3 se obtuvieron perlas esféricas. El uso combinado de los agentes de suspensión fue más apropiado que usarlos por separado, debido al producto de látex y la baja conversión de los monómeros para AG y PVA, respectivamente. El aumento del % DVB de 18,8 a 50% mejoró la resistencia mecánica de la cubierta polimérica, aumentando el rendimiento de reacción hasta un 84,7% y manteniendo la encapsulación TOMAC (36,0%) y la esfericidad de las microcápsulas. El tamaño de partícula obtenido (40 μm) indicó que la principal aplicación de este material será en lechos fluidizados o en reactores perfectamente mezclados. En base a los resultados experimentales, una relación de masa AG:PVA de 1:1, una relación de volumen TOMAC:tolueno de 1:3 y un 50% de DVB se establecieron como las mejores condiciones para producir este tipo de microcápsulas, permitiendo su reproducción en una planta a escala piloto. Además, los altos valores del coeficiente de distribución para la remoción de mercurio confirman el éxito de este proceso de optimización.

Polyurethane (PU) is one of the most important polymers with a global production of 17.565 million tons, which makes its recycling an urgent task. Besides, the main goal of PU recycling is to recover constituent polyol as a valuable raw material that allows to obtain new PU with suitable properties. Split-phase glycolysis can be considered the most interesting PU recycling process since provides high-quality recovered products in terms of polyol purity. The aim of this work was to evaluate several recovered polyols as replacement of the raw flexible polyether polyol in the synthesis of new flexible PU foams. These recovered polyols come from the split-phase glycolysis of different types of PU foams and employing as cleavage agents diethylene glycol or crude glycerol (biodiesel byproduct). The influence of the foam waste type and of the cleavage agent on the foams properties was analyzed. The recovered polyols were evaluated by performing several foaming tests according to the method of free expansion foaming of conventional flexible foam. Synthesized flexible foams containing different proportions of recovered polyols were characterized by means of scanning electron microscopy, density and tensile properties; obtaining similar and sometimes even better values compared to the foams manufactured from commercial polyols., El poliuretano (PU) es uno de los polímeros más importantes con una producción mundial de 17.565 millones de toneladas, lo que hace de su reciclaje una tarea urgente. Además, el objetivo principal del reciclaje de PU es recuperar el poliol constituyente como una materia prima valiosa que permita obtener nuevo PU con propiedades adecuadas. La glucólisis en fase dividida puede considerarse el proceso de reciclaje de PU más interesante, ya que proporciona productos recuperados de alta calidad en términos de pureza de polioles. El objetivo de este trabajo fue evaluar varios polioles recuperados como reemplazo del poliéter poliol flexible crudo en la síntesis de nuevas espumas de PU flexibles. Estos polioles recuperados provienen de la glucólisis en fase dividida de diferentes tipos de espumas de PU y empleando como agentes de escisión dietilenglicol o glicerol crudo (subproducto del biodiésel). Se analizó la influencia del tipo de residuo de espuma y del agente de desdoblamiento sobre las propiedades de las espumas. Los polioles recuperados se evaluaron realizando varios ensayos de espumado según el método de espumado de expansión libre de espuma flexible convencional. Las espumas flexibles sintetizadas que contenían diferentes proporciones de polioles recuperados se caracterizaron mediante microscopía electrónica de barrido, densidad y propiedades de tracción; obteniendo valores similares ya veces incluso mejores en comparación con las espumas fabricadas a partir de polioles comerciales. © 2017 Wiley Periodicals, Inc. J. Appl. polim. ciencia Las espumas flexibles sintetizadas que contenían diferentes proporciones de polioles recuperados se caracterizaron mediante microscopía electrónica de barrido, densidad y propiedades de tracción; obteniendo valores similares ya veces incluso mejores en comparación con las espumas fabricadas a partir de polioles comerciales. © 2017 Wiley Periodicals, Inc. J. Appl. polim. ciencia Las espumas flexibles sintetizadas que contenían diferentes proporciones de polioles recuperados se caracterizaron mediante microscopía electrónica de barrido, densidad y propiedades de tracción; obteniendo valores similares ya veces incluso mejores en comparación con las espumas fabricadas a partir de polioles comerciales.