Poliamidas aromáticas con heterociclos en la cadena principal y lateral. Aplicación a la extracción/eliminación de cationes contaminantes en medios acuosos.

Las investigaciones en el campo de las macromoléculas se centran principalmente en la síntesis de nuevos monómeros y en el estudio de las propiedades de los nuevos polímeros derivados de ellos. El Grupo de Investigación en el que se ha inscrito este estudio ha llevado a cabo numerosos estudios dirigidos a la mejora de las propiedades de las poliamidas aromáticas mediante la modificación química de la composición de poliamidas convencionales, y más concretamente poliisoftalamidas. El trabajo que se expone en esta Memoria se corresponde con investigaciones realizadas sobre las propiedades de cinco nuevas poliamidas y copoliamidas con subunidades 1,2,4-triazol en la cadena principal y en la estructura lateral. Los polímeros se preparan por polimerización de dos tipos de monómeros nuevos: diácidos aromáticos y un aminoácido. Uno de los objetivos perseguidos con la inclusión del heterociclo 1,2,4-triazol en las cadenas macromoleculares es permitir la preparación de polímeros con buenas propiedades mecánicas, térmicas y químicas, que pueden ser transformados en materiales capaces de interaccionar con cationes, lo cual es útil para aplicaciones relacionadas con materiales capaces de interaccionar selectivamente con analitos para la preparación de sensores, membranas permeaselectivas, lo que permite preparar fases sólidas para extracción de cationes contaminantes. En concreto, estas poliamidas se comportan como fases sólidas extractantes efectivas en la extracción/eliminación de cationes mercurio en medio acuoso observándose una eliminación de HgII en las condiciones de experimentación próxima al 100%. Este trabajo se divide en seis capítulos que describen las propiedades térmicas, mecánicas, difracción de rayos X a ángulos altos, solubilidad, absorción de agua y extracción sólido-líquido de las nuevas poliamidas

Polímeros funcionales: aplicaciones como sensores y materiales de altas prestaciones

El trabajo que conforma Tesis Doctoral titulada Polímeros funcionales. Aplicaciones como sensores y materiales de altas prestaciones se encuadra en el ámbito científico y tecnológico de los materiales avanzados para aplicaciones específicas. En este marco se han diseñado materiales funcionales con aplicaciones en protección y seguridad civil, industria y medio ambiente. Concretamente se han elaborado sensores químicos poliméricos cromogénicos y fluorogénicos de explosivos (TNT), cationes metálicos, alta acidez y agua. Los receptores orgánicos utilizados son insolubles en agua, pero su incorporación a polímeros con el grado de hidrofilia adecuada ha permitido la obtención de polímeros solubles en este medio, así como geles capaces de detectar a las moléculas de interés en entornos acuosos. Además, se han preparado materiales de altas prestaciones, concretamente poliamidas aromáticas, con grupos funcionales que aportan características de interés como color, potencial funcionalización adicional, o mejores propiedades mecánicas y térmicas.The work constituting this Thesis lies within the scientific and technological field of advanced materials for specific applications. In this framework, functional materials with applications in civil protection and security, industry and environment have been designed. Specifically, fluorogenic and chromogenic polymeric chemosensors towards explosives (TNT), metal cations, high acidity and water were developed. The organic receptors used were insoluble in water, but their incorporation into polymers with the appropriate degree of hydrophilicity allowed for the preparation of water soluble polymers, as well as gels capable of detecting target molecules in aqueous environments. In addition, high performance materials were prepared, particularly aromatic polyamides containing functional groups that provide interesting features, such as color, additional functionalization potential, or better mechanical and thermal properties

Smart Polymers for Food and Water Quality Control and Safety

A large number of annual cases of diseases and deaths related to spoiled or contaminated food, and the amount of food waste are a matter of socio-economic impact, highlighting the need for a fast, easy, cheap, available, and real-time determination of food quality and safety. To ensure this, physical and chemical food quality indicators such as humidity, temperature, gases, pH, microorganisms, pesticides, etc., should be controlled and monitored during production, transportation, storage, and consumption. In this sense, smart polymers are raised as useful tools to facilitate this task. These polymers are sensitive to variations in the microenvironment, modifying their properties and/or generating a response that can be measured. Due to their versatility, these materials can be part of the food packaging to inform the consumers or be used as a measuring tool to determine the state of the food. This chapter envisaged the concept of smart polymers, the types, and their main applications for determining food quality and ensuring food and beverage safety.We gratefully acknowledge the financial support provided by FEDER (Fondo Europeo de Desarrollo Regional), the Spanish AEI (State Research Agency, PID2020-113264RBI00/AEI/10.13039/501100011033 and PID2019-108583RJI00/AEI/10.13039/501100011033), and "La Caixa" Foundation (under agreement LCF/PR/PR18/51130007). We also acknowledge the financial support provided by the Spanish Ministerio de Universidades (Plan de Recuperación, Transformación y Resiliciencia, European Union-NextGenerationEU, Universidad Politécnica de Madrid (RD 289/2021) and Universidad Autónoma de Madrid (CA1/RSUE/2021-00409))

Metal-free organocatalysts for high hydrolytic stability single component polyurethane adhesives and their application in decorative insulation facades manufacturing

We focused on developing polyurethane (PU) adhesives with superior ambient thermal and hydrolytic stability, a crucial factor for industrial productivity. Our approach involved creating PU prepolymers that can withstand varying temperatures in ambient conditions. These prepolymers consist of conventional isocyanate-terminated polyurethane and metal-free acid:base organic catalysts, with the stability of the adhesive relying on the organocatalyst employed. We tested a series of 11 latent organocatalysts derived from the reaction between 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and various acids. Among these, the catalyst based on 1-naphthoic acid exhibited exceptional stability, lasting at least 3 h at 60 ◦C and an average relative humidity of 65% under vigorous stirring. We assessed this stability using a fan-based stirrer and analyzed the curing conditions kinetically through DSC. Furthermore, our adhesive formulation is environmentally friendly as it is free of metals, specifically tin (typically present in catalysts such as dibutyltin dilaurate). This quality enhances its sustainability. To validate the practical applicability of the adhesives, we conducted tests using decorative facade models composed of siliciclastic sandstone extracted from a quarry in Vilviestre del Pinar (Burgos, Spain. Latitude: 41.951024◦N, longitude: 3.078283◦W) and extruded polystyrene (XPS). The results demonstrated the excellent hydrolytic and thermal stability of the adhesives, highlighting their significant potential for panel manufacturing in this context.This work was supported by the Regional Government of Castilla y León (Junta de Castilla y León) and by the Ministry of Science and Innovation MICIN and the European Union NextGeneration EU PRTR. Author José Miguel García received grant PID2020-113264RB-I00 funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe”. Author Miriam Trigo-López received grant PID2019-108583RJ-I00 funded by MCIN/AEI/10.13039/501100011033. Author Saul Vallejos received grant BG22/00086 funded by Spanish Ministerio de Universidades

Heteroaromatic polyamides with Improved thermal and mechanical properties

We prepared high-performance aromatic copolyamides, containing bithiazole and thiazolo-thiazole groups in their main chain, from aromatic diamines and isophthaloyl chloride, to further improve the prominent thermal behavior and exceptional mechanical properties of commercial aramid fibers. The introduction of these groups leads to aramids with improved strength and moduli compared to commercial meta-oriented aromatic polyamides, together with an increase of their thermal performance. Moreover, their solubility, water uptake, and optical properties were evaluated in this work.Fondo Europeo de Desarrollo Regional and both the Spanish Ministerio de Economía, Industria y Competitividad (MAT2017-84501-R) and the Consejería de Educación, Junta de Castilla y León (BU306P18) is gratefully acknowledged. M.T.L. also thankfully acknowledges the Spanish Ministerio de Ciencia e Innovación (PID2019-108583RJ-I00/AEI/10.13039/501100011033

From Classical to Advanced Use of Polymers in Food and Beverage Applications

Polymers are extensively used in food and beverage packaging to shield against contaminants and external damage due to their barrier properties, protecting the goods inside and reducing waste. However, current trends in polymers for food, water, and beverage applications are moving forward into the design and preparation of advanced polymers, which can act as active packaging, bearing active ingredients in their formulation, or controlling the head-space composition to extend the shelf-life of the goods inside. In addition, polymers can serve as sensory polymers to detect and indicate the presence of target species, including contaminants of food quality indicators, or even to remove or separate target species for later quantification. Polymers are nowadays essential materials for both food safety and the extension of food shelf-life, which are key goals of the food industry, and the irruption of smart materials is opening new opportunities for going even further in these goals. This review describes the state of the art following the last 10 years of research within the field of food and beverage polymer’s applications, covering present applications, perspectives, and concerns related to waste generation and the circular economy.This work was supported by the Regional Government of Castilla y León (Junta de Castilla y León) and by the Ministry of Science and Innovation MICIN and the European Union NextGeneration EU PRTR. The project leading to these results has received funding from “La Caixa” Foundation, under the agreement LCF/PR/PR18/51130007. We also gratefully acknowledge the grant PID2020-113264RB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. Finally, we want to acknowledge the funding from Ministerio de UniversidadesEuropean Union in the frame of NextGenerationEU RD 289/2021 (Universidad Politécnica de Madrid and Universidad Autónoma de Madrid-CA1/RSUE/2021-00409)

Photopolymerization of ionic liquids in flexible microporous aramids for ion conductive solid polyelectrolytes

This work presents the preparation of novel solid polymer electrolytes based on flexible microporous aramids filled with photopolymerized ionic liquids and lithium salt. The materials combined a high ionic conductivity with the mechanical and thermal characteristics of the aramids, including also good flexibility and handleability. First, a simple casting process was followed to obtain microporous aramids with an interconnected channel morphology. In a second step, this channel structure was filled with a solution of non-commercial photopolymerizable ionic liquid, commercial ionic liquids and the lithium salt, followed by UV irradiation to obtain the conducting aramids. Ionic conductivity of the materials was studied at 25 °C, and also in the temperature range between −50 to 90 °C, together with SEM analyses of the filled porous structure and thermal properties, to fully characterize the photopolymerization process of the ionic liquids inside the porous structure. The materials showed high ionic conductivity values together with excellent thermal and mechanical properties, indicating their viability as flexible and thermally stable solid electrolytes.FEDER (Fondo Europeo de Desarrollo Regional) and both the Spanish Ministerio de Economía, Industria y Competitividad (MAT2017-84501-R and MAT2017-88923-P), the Consejería de Educacion-Junta ´ de Castilla y Leon ´ (BU306P18) and the Spanish Ministerio de Ciencia e Innovacion ´ (PID2019-108583RJ-I00/AEI/10.13039/501100011033)

Aromatic polyamides and acrylic polymers as solid sensory materials and smart coated fibres for high acidity colorimetric sensing

We synthesized a solid sensory material for the extraction, detection and quantification of iron(III) in aqueous media. The material is a film-shaped colorless polymer membrane that exhibits gel behavior. The Fe(III) extraction and sensing characteristics are imparted by a new monomer derived from a natural product (i.e., Kojic acid), which exhibits chelating properties toward Fe(III). The sorption of Fe(III) on the membrane in water has been thoroughly characterized, including the sorption kinetics, sorption isotherms and profiles as a function of the pH. Fe(III) sorption followed pseudo first-order kinetics and required approximately 30 min to reach equilibrium. The maximum sorption capacity was approximately 0.04 mmol/g, and the sorption isotherms are well modeled by the Langmuir equation. The complexes that were found in the solid phase are in good agreement with those previously identified in the aqueous phase. Moreover, the sorption is highly specific (i.e., a recognition process) and results from the formation of a colored complex (iron(III)-Kojic acid derivative moieties). Therefore, the colorless sensory membrane turns red upon immersion in aqueous solutions containing Fe(III). The color output allows for both the qualitative visual determination of the Fe(III) concentration as well as also titration of Fe(III) using a) a UV/vis technique (limit of detection of 3.6 × 10−5 M; dynamic range of five decades, lower concentration = 1.65 × 10−6 M) and b) a computer vision-based analytical chemistry approach via color definition of the sensory membrane (RGB parameters) obtained from an image recorded with a handy device (e.g., a smartphone) (limit of detection of 2.0 × 10−5 M).Spanish Ministerio de Economía y Competitividad-Feder (MAT2011-22544 and MAT2014-54137-R) and by the Consejería de Educación – Junta de Castilla y León (BU232U13

Microcellular foamed aromatic polyamides (aramids). Structure, thermal and mechanical properties

We have deeply diminished the density of high performance aromatic polyamides or aramids. Thus, we have prepared microcellular films that at the same time maintain the outstanding thermal and mechanical properties characteristic of these high performance materials. Two different cellular aramids were produced, based on commercial poly(m-phenylene isophthalamide), one of them with an additional azide group. Microcellular structures have been obtained by adding ionic liquids combined to ScCO2 foaming process, with cell sizes between 0.6 and 4.7 µm and cell densities between 109 and 1011 cells cm3. The density was lowered for the commercial poly(m-phenylene isophthalamide) (Nomex® and Teijin Conex®) from 1.43 to 0.62 g cm−3 and from 1.48 to 0.31 g cm3 for the aramid containing the azide group. Foams present the following thermal and mechanical properties: 5% weight loss observed at T > 400 °C and relative Young modulus and tensile strength of 1.2 GPa (g cm−3)−1 and 60 MPa (g cm−3)−1, respectively.FEDER (Fondo Europeo de Desarrollo Regional) and the Spanish Agencia Estatal de Investigación (MAT2017-84501-R

Segmented-block poly(ether amide)s containing flexible polydisperse polyethyleneoxide sequences and rigid aromatic amide moieties

We describe the synthesis and characterization of three novel aromatic diamines containing oxyethylene sequences of different lengths. These diamines were polymerized using the low-temperature solution polycondensation method with isophthaloyl chloride (IPC), terepthaloyl chloride (TPC), [1,1’-biphenyl]-4,4’-dicarbonyl dichloride (BDC), and 4,4′-oxybis(benzoyl chloride) (OBE), obtaining twelve poly(ether amide)s with short segments of polydisperse polyethyleneoxide (PEO) sequences in the polymer backbone. These polymers show reasonably high molecular mass materials (Mw > 12,000), and the relationship between their structure and properties has been carefully studied. Compared with conventional polyamides containing monodisperse PEO sequences, the polydispersity of the PEO segments within the structural units exerts a significant influence on the crystallinity, flexibility, solubility, and the thermal properties of the polymers. For instance, the all-para oriented polyamides (TPCP-A), with an average number of 8.2 ethylenoxide units per structural unit can be transformed conventionally (Tm = 259 °C) in comparison with thermally untransformable polymer with 2 ethylenoxide units (Tm = 425 °C)FEDER (Fondo Europeo de Desarrollo Regional), the Spanish Agencia Estatal de Investigación (PID2020-113264RB-I00/AEI/10.13039/501100011033) and (PID2019-108583RJ-I00/AEI/ 10.13039/501100011033), and the Consejería de Educación—Junta de Castilla y León (BU306P1