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The ageing of wine in oak barrels represents a critical stage in winemaking at which product alteration can occur due to bacteria, yeasts or fungal growth. The control of microorganisms, such as yeasts of the Brettanomyces genus (Guzzon et al, 2011) and acetic acid bacteria (Kocijan et al, 2021), is of great importance, since the alterations that they can cause in wine can be very serious and cause great economic losses.

In current research, there is a widespread idea that the history of the universal basic income proposal begins with Thomas Paine and his famous pamphlet Agrarian Justice, published in Paris in 1797 in the context of the French Revolution and under its intellectual influence. In this article, the author rescues a largely unknown text by Paine published without a title under the pen name “Amicus” in the Pennsylvania Magazine in 1775. The transcript demonstrates that he was already reflecting on the proposal at least twenty years earlier, shortly after he arrived in the American colonies. The debates and discussions in which Paine wants to intervene cannot be the same in Wilkes's England as in revolutionary France. Locating the proposal of a universal basic income in this context has important implications for the history of its conception. It compels us to highlight the importance of Paine's experience as an exciseman in England, as well as the context of popular radicalism and religious dissent that prevailed in the country at the start of the Industrial Revolution.

Background and Objective: Bulbar dysfunction is a term used in amyotrophic lateral sclerosis (ALS). It refers to motor neuron disability in the corticobulbar area of the brainstem which leads to a dysfunction of speech and swallowing. One of the earliest symptoms of bulbar dysfunction is voice deterioration characterized by grossly defective articulation, extremely slow laborious speech, marked hypernasality and severe harshness. Recently, research efforts have focused on voice analysis to capture this dysfunction. The main aim of this paper is to provide a new methodology to diagnose this dysfunction automatically at early stages of the disease, earlier than clinicians can do. Methods: The study focused on the creation of a voiceprint consisting of a pattern generated from the quasi-periodic components of a steady portion of the five Spanish vowels and the computation of the five principal and independent components of this pattern. Then, a set of statistically significant features was obtained using multivariate analysis of variance and the outcomes of the most common supervised classification models were obtained. Results: The best model (random forest) obtained an accuracy, sensitivity and specificity of 88.3%, 85.0% and 95.0% respectively when classifying bulbar vs. control participants but the results worsened when classifying bulbar vs. no-bulbar patients (accuracy, sensitivity and specificity of 78.7%, 80.0% and 77.5% respectively for support vector machines). Due to the great uncertainty found in the annotated corpus of the ALS patients without bulbar involvement, we used a safe semi-supervised support vector machine to relabel the ALS participants diagnosed without bulbar involvement as bulbar and no-bulbar. The performance of the results obtained increased, especially when classifying bulbar and no-bulbar patients obtaining an accuracy, sensitivity and specificity of 91.0%, 83.3% and 100.0% respectively for support vector machines. This demonstrates that our model can improve the diagnosis of bulbar dysfunction compared not only with clinicians, but also the methods published to date. Conclusions: The results obtained demonstrate the efficiency and applicability of the methodology presented in this paper. It may lead to the development of a cheap and easy-to-use tool to identify this dysfunction in early stages of the disease and monitor progress. This work was approved by the Research Ethics Committee for Biomedical Research Projects (CEIm) at the Bellvitge University Hospital in Barcelona and was supported by the Ministerio de Economía y Competitividad (TIN2017-84553-C2-2-R) and the Ministerio de Ciencia e Innovacion (PID2020-113614RBC22). AT is a member of CIMNE, a Severo Ochoa Centre of Excellence (2019-2023) under grant CEX2018-000797-S, funded by MCIN/AEI/10.13039/501100011033. The Neurology Department of the Bellvitge University Hospital in Barcelona permitted the recording of the voices of the participants in its facilities. The clinical records were provided by Carlos Augusto Salazar Talavera. Dr. Marta Fulla and Maria Carmen Majos Bellmunt contributed advice about the process of eliciting the sounds.

BACKGROUND Bulbar involvement is a term used in amyotrophic lateral sclerosis (ALS) that refers to motor neuron impairment in the corticobulbar area of the brainstem, which produces a dysfunction of speech and swallowing. One of the earliest symptoms of bulbar involvement is voice deterioration characterized by grossly defective articulation; extremely slow, laborious speech; marked hypernasality; and severe harshness. Bulbar involvement requires well-timed and carefully coordinated interventions. Therefore, early detection is crucial to improving the quality of life and lengthening the life expectancy of patients with ALS who present with this dysfunction. Recent research efforts have focused on voice analysis to capture bulbar involvement. OBJECTIVE The main objective of this paper was (1) to design a methodology for diagnosing bulbar involvement efficiently through the acoustic parameters of uttered vowels in Spanish, and (2) to demonstrate that the performance of the automated diagnosis of bulbar involvement is superior to human diagnosis. METHODS The study focused on the extraction of features from the phonatory subsystem—jitter, shimmer, harmonics-to-noise ratio, and pitch—from the utterance of the five Spanish vowels. Then, we used various supervised classification algorithms, preceded by principal component analysis of the features obtained. RESULTS To date, support vector machines have performed better (accuracy 95.8%) than the models analyzed in the related work. We also show how the model can improve human diagnosis, which can often misdiagnose bulbar involvement. CONCLUSIONS The results obtained are very encouraging and demonstrate the efficiency and applicability of the automated model presented in this paper. It may be an appropriate tool to help in the diagnosis of ALS by multidisciplinary clinical teams, in particular to improve the diagnosis of bulbar involvement.

Two series of aromatic poly(ortho-hydroxyamide)s (poly(o-hydroxyamide)s, HPAs) were prepared by reaction of two diamines, 2,2-bis(3-amino-4-hydroxyphenyl) propane (APA) and 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (APAF), with four aromatic diacid chlorides; terephthaloyl dichloride (TPC), isophthaloyl dichloride (IPC), 2,2-bis[4-chlorocarbonylphenyl)hexafluoropropane (6FC) and 4,4¿-sulfonyldibenzoyl dichloride (DBSC). Amorphous HPAs with high molecular weights (inherent viscosities higher than 0.5 dL/g) and relatively high glass transition temperatures (220¿280 °C) were obtained. Dense membranes of HPAs were able to undergo a thermal rearrangement (TR) process to polybenzoxazoles (ß-TR-PBOs) heating at moderate temperatures (between 250 and 375 °C), and their complete conversion was reached at a temperature below 375 °C, depending on the o-hydroxy diamine moiety, APA and APAF. The ß-TR-PBOs films derived from APAF showed a higher thermal stability and higher Tg than those from APA. Gas separation properties of TR-PBOs membranes were superior to those of their poly(o-hydroxyamide) precursors, particularly for the following gas pairs: O2/N2, CO2/CH4, He/CH4 and He/CO2., The financial support provided, by the Spain's MINECO (MAT2013- 45071-R and MAT2016-76413-C2-1-R and MAT2016-76413-C2-2-R AEI/FEDER, UE and CTQ 2012-31076) is greatly acknowledged. This research was also supported by the Korea Carbon Capture & Sequestration R&D Center (KCRC) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning (NRF-2014M1A8A1049305). We are also indebted to the Spanish Junta de Castilla y León for its funding help (project VA248U13). Authors kindly acknowledge Sara Rodriguez for carrying out the gas separation tests and Judit González Jarillo for performing polymer characterization

Catalytic CO methanation technology can be improved by process intensification, i.e. enabling higher energy efficiency and process sustainability. Here, thin-film composite membranes (TFCM) were developed for in-situ water removal in a catalytic membrane reactor (CMR) for the Sabatier process. The selective separation layer (1.4 μm-thick) of the composite membrane is made of the polyimide 6FDA-6FpDA, a glassy polyimide, which exhibits high permeability and selectivity together with stable function at unprecedented high temperatures (>200 °C), compared to polyimides reported until now (90 °C), thus matching the temperature range of Sabatier reactors. Remarkably, TFCM developed in this work, allow to extract an outstanding amount of water up to 1 m/(m·h·bar) at 260 °C. TFCM was implemented for the water removal from the methanation reaction in a CMR operated at 260 °C and using Ni-Todorokite as catalyst. The TFCM-mediated water-extraction enabled to raise both catalytic stability and activity during CMR operation. CO conversion stability was greatly improved exhibiting a conversion value of 72 % during the course of the reaction (21 % increase in CO conversion), with a water removal of 12.5 % and specific flux of ∼100 g·h m., This work was financially supported by the Spanish Government (SVP-2014-068356, SVP-2014-068713, RTI2018-102161 and IJCI-2016-28330 grants) and Generalitat Valenciana (PROMETEO/2018/006 grant).

Aromatic polyimides containing an ortho-allyloxy group with different ratios (in the range of 10–100%) of the ortho-allyloxy to ortho-hydroxy units were synthesized. The allyl ether synthesis was done via a post-polymerization Williamson etherification reaction. Thermally induced Claisen-rearrangement of the allyloxy-phenyl unit was conducted in the solid-state, followed by isothermal treatments at 250 °C leading to a crosslinked ortho-hydroxy containing polyimide. Further thermal annealing at 350 °C was employed to achieve a high imide-to-benzoxazole conversion, commonly described as the thermal rearrangement process (TR). The influence of the degree of modification on the crosslinking reaction as well as the imide-to-benzoxazole conversion temperature and the rate were studied by means of TG-FTIR, DSC and dielectric spectroscopy. A nearly linear change of the material properties, such as film density, d-spacing and gel-fraction, with an increasing number of allylated units was observed. Additionally, an incline of the permeability, due to an increase of the free volume elements, was observed. Moreover, the polymer chain mobility in terms of relaxation times was demonstrated to depend on the degree of allylation, which in turn led to a reduction of the TR temperature of about 80 °C compared to the pristine polyimide. The thermally induced imide-to-benzoxazole rearrangement occurred already to a large extent of 77% at 350 °C. In comparison, the pristine polymer showed only a conversion of 20%. Furthermore, the observed HPI-to-PBO conversions at 350 °C surpassed those of various other reported TR polyimides treated at even higher temperatures of 400 to 450 °C. Side-reactions and degradation that usually accompany treatments at 400 °C and above might be avoided at lower treatment temperatures of 350 °C.

A new way to obtain functionalized polymers by 3,3′-sigmatropic Claisen rearrangement has been developed and identified. The process was identified for three polyamides and three allyl-derivatives with different functional groups and rigidity. The Claisen rearrangement process seems to be independent of the polymeric structure, and it is only affected by the allyl functionality. The polymeric structure conditioned the rate of the process. The influence of polymer chain and allyl-derivatives on a cyclodehydration process was also studied. The cyclodehydration reaction is mainly affected by the rigidity of the polymer chain; therefore, it is influenced by the corresponding alkenyl structure. This work demonstrates the great potential of this approach that allows, by a simple and well-known process, the alkene functionalization of the polymeric chain in order to create a great variety of new high-performance materials for the application of these polymers in multiple fields.

A strong effect of the chemical composition and imidization method on physical and especially on gas transport properties of polyimides was demonstrated. Two fluorinated diamines 6FpDA and bisAPAF were polymerized in different ratios, employing the fluorinated dianhydride 6FDA to get polyimides with nine different compositions. For all synthesized materials three imidization methods were used: azeotropic, thermal, and chemical. The 6FDA-6FpDA homopolymers showed significant differences in the gas transport properties, indicating the influence of the imidization route on the final properties of the polyimides. For polyimides containing bisAPAF, the chemical composition played an important role due to the exchange of the hydroxyl groups by acetate groups leading to different interchain interactions. The gas transport was mainly controlled by the chain packing for thermally and azeotropically imidized polymers with bisAPAF contents lower than 30 mol %. For bisAPAF contents above 50 mol % the gas transport wa...

In this work, we studied CO 2 sorption and transport in two series of aliphatic-aromatic copolyimide membranes, as a function of chemical formulation, pressure and temperature. Such materials are formed by two distinct phases with rather different properties: the first one is formed of rubbery polyether segments (poly(propylene oxide) (PPO) or poly(ethylene oxide) (PEO)), characterized by favorable energetic interactions with CO 2 and high flexibility, which endows the copolymers with high CO 2 permeability, suitable for capture processes. The second phase is formed by hard glassy polyimide blocks, randomly distributed at the microscopic level, which provide the necessary thermal, chemical and mechanical stability. Previous studies indicate that CO 2 permeability increases with increasing the amount of polyether phase in the copolymers; in the present work we investigate more deeply the interactions and synergies occurring between the two phases, by focusing separately on the CO 2 solubility and diffusivity terms that contribute to permeability. In particular, by studying the shape of the solubility isotherm, as well as the values of diffusivity, sorption enthalpy and activation energy, we were able to monitor the transition from a glassy-like to a rubbery-like behavior as the fraction of rubbery component in the copolymer increases. The data indicate that polyether enhances CO 2 permeability by acting mostly on diffusivity, while the solubility contribution is less affected on a quantitative basis. However, the qualitative behavior of solubility allows understanding the nature of interactions between the two phases. In particular, by using a simple additive approach to estimate the CO 2 solubility of the copolymer, and the Non-Equilibrium Lattice Fluid (NELF) to evaluate the CO 2 solubility in the pure homopolymers, one concludes that the copolymers sorption behavior is “ideal”, i.e. purely additive, indicating a good combination of the two phases. The copolymer volume, on the other hand, shows a contraction upon combination of the two phases. The NELF modeling of solubility data allows attributing such a contraction only to the glassy phase, whose excess free volume is reduced in the presence of the rubbery portion in the copolymer, which possibly partly occupies such excess volume, indicating a strong interpenetration of the two phases.

Novel selective polymeric thin-film composite membranes (TFCMs) for applications at elevated temperatures were developed. Thin selective layers of the polyimides Matrimid 5218&reg, and 6FDA-6FpDA were cast on a developed polybenzimidazole (PBI) porous support prepared by a phase inversion process. The TFCM properties were investigated with different gases in a wide temperature range, including temperatures up to 270 &deg, C. The membranes showed very high thermal stability and performed well at the elevated temperatures. The development of highly thermally resistant polymeric membranes such as these TFCMs opens opportunities for application in high-temperature integrated processes, such as catalytic membrane reactors for the water-gas shift reaction in order to maximize H2 yield.

Three polyimides and six inorganic fillers in a form of nanometer-sized particles were studied as thick film solution cast mixed matrix membranes (MMMs) for transport of CO2, CH4 and H2O. Gas transport properties and electron microscopy images indicate good polymer-filler compatibility for all membranes. The only filler type which demonstrated good distribution throughout the membrane thickness at 10 wt. % loading was BaCe0.2Zr0.7Y0.1O3 (BCZY). The influence of this filler on MMM gas transport properties was studied in detail for 6FDA-6FpDA in a filler content range from 1 to 20 wt.% and for Matrimid® and P84® at 10 wt. % loading. The most promising result was obtained for Matrimid® - 10wt% BCZY MMM, which showed improvement in CO2 and H2O permeabilities accompanied by increased CO2/CH4 selectivity and high water selective membrane at elevated temperatures without H2O/permanent gas selectivity loss.

Three polyimides and six inorganic fillers in a form of nanometer-sized particles were studied as thick film solution cast mixed matrix membranes (MMMs) for the transport of CO2, CH4, and H2O. Gas transport properties and electron microscopy images indicate good polymer-filler compatibility for all membranes. The only filler type thatdemonstrated good distribution throughout the membrane thickness at 10 wt.% loading was BaCe0.2Zr0.7Y0.1O3 (BCZY). The influence of this filler on MMM gas transport properties was studied in detail for 6FDA-6FpDA in a filler content range from one to 20 wt.% and for Matrimid® and P84® at 10 wt.% loading. The most promising result was obtained for Matrimid®—10 wt.% BCZY MMM, which showed improvement in CO2 and H2O permeabilities accompanied by increased CO2/CH4 selectivity and high water selective membrane at elevated temperatures without H2O/permanent gas selectivity loss.

Los proyectos pilotos de Renta Básica Universal (RBU) que se han ido implantando en distintos países del mundo han generado en Europa un gran interés, tanto por los datos recopilados, como por su alcance teórico. Este artículo analiza la evidencia empírica y modelos de experimentación de las políticas de RBU, a partir del mayor o menor grado de información sobre la previsibilidad de su impacto social que nos proporciona cada uno de ellos. Para ello revisamos la intención, el diseño y los resultados obtenidos de los diferentes casos y modelos experimentales a lo largo del tiempo y en diferentes países. En general, encontramos que ninguno de estos experimentos es en sí mismo suficiente para dotarnos de la evidencia que permita anticipar el impacto en todas las variables implicadas en el desarrollo de una RBU a largo plazo en contextos concretos. Pero al mismo tiempo este conjunto de evidencias traslada la carga de prueba hacia los detractores de la RBU: ninguno de sus efectos negativos queda probado con el análisis empírico. Este conjunto de evidencias apunta a una heterogeneidad de efectos que debe ser una referencia insoslayable para reducir la incertidumbre sobre el impacto de la RBU, para incorporar al análisis nuevas variables relevantes o para mejorar el diseño de su implementación. The different pilot projects of Universal Basic Income (UBI) that have been implemented all over the world have raised an intense interest in Europe, both for the data they gathered and for their theoretical implications. This article analyzes the empirical evidence and the different models of experimentation that have been at work in UBI policies, with the aim to measure to what extent they are capable of offering a certain amount of predictability on UBI social impact. In order to do it, the intention, design and results obtained from different pilot projects and experimental models over time and in different countries are thouroughly analysed. In broad terms, we find that none of these experiments is capable to furnish evidence that would make it possible to anticipate the joint impact of all the variables involved in the development of UBI in the long-term and in specific contexts. Nevertheless, this same evidence can also be used to unload the burden of proof to the detractors of UBI, as empirical analysis does not show any sure negative effects, either. In conclusion, it can be stated that the heterogeneity of effects brought forward by the implementation of UBI should be viewed as an unavoidable reference in order to reduce the uncertainty about its impact, and the effort should be made to incorporate new relevant variables into the analysis or to improve the design of its implementation.

Herein, a new approach to achieve gas separation materials with improved resistance to plasticization (obtained by partial pyrolysis of new polyimide blends) is presented. Blends of an aromatic polyimide (formally, 6FDA-6FpDA) and aliphatic-aromatic copolyetherimides based on the same polyimide in combination with other aliphatic polyimides, having polyethylene oxide moieties, were obtained. After their synthesis and characterization, a selective elimination of the polyether by thermal treatment was carried and the obtained partially pyrolyzed materials were tested as gas separation membranes. For neat blends, permeability was shown to decrease when PEO content increases. This effect is due to polyethylene oxide (PEO) chains encroaching on free volume because phase segregation was minimized. When these blends were subjected to thermal treatment at relatively low temperatures in air or in N2, it was clearly observed that all the polyether moieties were selectively eliminated from the structure, which gave rise to an increase of permeability. Higher permeabilities were obtained after a thermal treatment at 390 °C in N2. Degradation of PEO chains after a 290 °C treatment in air produced materials with permeability values lower than those observed under N2. In both cases, even though PEO was selectively and wholly eliminated, permeability was not totally recovered to give the values observed for neat 6FDA-6FpDA due probably to a combination of shrinkage and crosslinking of the membrane produced during the thermal process. Crosslinking provides the materials with an increased resistance to plasticization. In particular, the best improvement against plasticization proceeded from the thermal treatments of blends at 290 °C in air., Authors would like to thank the Spanish MINECO for the financial support of this work within the frame of the Plan Nacional de I+D+I through the research MAT2016-76413-C2-R1 and MAT2016-76413-C2- R2.

Producción Científica, A complete series of aliphatic-aromatic copoly(ether-imide)s has been synthesized in this work. All these copoly(ether-imide)s had the same structure, BPDA-PEOX-ODA, but different lengths of PEO in the final polymer. These copolymers have been thermally treated and characterized by several techniques. A direct relationship between the temperature of treatment, the improvement of phase segregation, and permeability has been demonstrated. The Maxwell model has been applied to predict permeability (for CO2, CH4 and N2) and it has been found that when the segregated PEO can be considered to be amorphous – it is at high temperatures when crystallinity disappears – the model fits reasonably well. This confirms that the aliphatic and aromatic portions of the copolymer behave approximately as a bi-phase of disperse domains within a continuous matrix. Results show that permeability is higher when the PEO chains are longer – when there is no crystallinity, or any kind of internal bonds, distorting the results – while selectivity doesn´t depend on the PEO length in the copolymer. Remarkable are the results for the CO2/N2 gas pair, with selectivity-versus-permeability very near to the Robeson‘s upper bound at 30 ºC and even in closer proximity to the corresponding trade off line for higher permeation temperatures., Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA248U13)

Producción Científica, A complete series of aliphatic aromatic copoly(etherimide)s, based on an aromatic dianhydride (BPDA), an aromatic diamine (ODA) and a diamino terminated poly(ethylene oxide) (PEO2000) of 2000 g/mol molecular weight, using different PEO contents, has been synthesized. Cast films of these copolymers have been thermally treated and characterized by FTIR-ATR, DSC, TGA and SAXS. It has been found that there is a direct relationship between phase segregation and permeability for increasing treatment temperatures. Results show that permeability is higher when PEO content increases in the copolymer. Selectivity for O2/N2 and CO2/CH4 gas pairs follows the same tendency, while those for CO2/N2, and CH4/N2 give higher selectivities for intermediate (30-40 %) PEO contents. Especially promising are the results for these two pairs of gases because materials with high permeability with high selectivity can be obtained. The Maxwell model has been applied to predict permeability (for CO2, CH4, O2 and N2) from known data for pure BPDA-ODA and neat PEO and it has been found that assuming PEO as the dispersed phase, the use of this equation is adequate for percentages up to approximately a 40 % over which we should assume that it is the aromatic part of the copolymer which plays the role of dispersed phase., Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13)

By removing anhydride groups from crosslinked copolyimide membranes at 430 °C, partially pyrolysed membranes were obtained and gas separation properties were evaluated and related to the content of labile groups. The spaces occupied by the linking anhydride groups prevailed as micropores, which greatly improved the gas transport properties. The release of the labile groups was confirmed by TGA and FT-IR spectroscopy which permitted us to establish that polymer main chains did not suffer any substantial change during the pyrolytic treatment. During the heating step new cross-linking points are created, no Tg below 450 °C could be observed and the process prevents the collapse of micropores. The pyrolysed membrane obtained from the precursor with the lowest content of anhydride groups showed the highest permeability values: 101, 25, 17 and 446 barrers to O 2 , N 2 , CH 4 and CO 2 respectively, and a selectivity to CO 2 /CH 4 of 26, good enough to place this membrane close to Robeson's new upper bound (2008), while the crosslinked precursor membrane fell below Robeson's old upper bound (1991).

Second generation of thermally rearranged polymers presents low temperatures for a complete rearrangement., Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications.

Copoly(ether-imide)s formed by the reaction of an aromatic dianhydride (BPDA), an aromatic diamine (ODA), and various aliphatic diamines (PEO-2000, PPO-2000, RT-1000, pTHF-1700, and pTHF-350) have ...

A set of copoly(ether-imide)s, formed by the reaction between an aromatic dianhydride (BPDA), a polyoxyalkyleneamine (poly(ethylene oxide) diamino terminated) (PEO-2000) and various aromatic diamines (PPD, BNZ, and ODA) under different thermal treatments, has been obtained and characterized. The existence of phase segregation in these copolymers has been confirmed by SAXS. It has also been proved that aromatic diamines having a hinge group, such as ODA, produce bigger segregated domains while short and rigid aromatic diamines give higher percentages of phase segregation. A direct relationship between gas permeability and percentage, and size of the domains, of the segregated phase has been obtained. Also, higher or similar selectivities have been observed as a function of the thermal treatment. In such way, the use of high temperatures during the thermal treatment, responsible of the improvement of the phase segregation, enhances the gas properties, producing materials with permeability/selectivity values close to the Robeson limit. In the case of the CH 4 /N 2 pair an interesting reverse selectivity has been observed probably due both to a specific interaction of the gas with the polymer and to an increase in the solubility of CH 4 in the soft segregated portions of the copolymer. The use of PPD as comonomer provides more phase segregation while the use of ODA gives bigger segregated domains. In terms of permselectivity the performances, for all the pairs of gases studied, follow the PPD > BNZ > ODA sequence when relatively low treatment temperatures are used while quite similar results for BNZ and ODA were observed when higher treatment temperatures are employed. This seems to indicate that the domains size is a key factor in the gas separation properties with a certain influence of the percentage of segregation. An adequate balance of short length with limited rigidity of the aromatic part should improve the properties of this kind of materials.

13 páginas, 19 figuras, 1 esquema, 7 tablas.-- El pdf es el borrador del artículo., Polyimides having long poly(ethylene oxide), PEO, moieties in the main chain have been synthesized by a classical two-steps polycondensation method with good yield and high molecular weight. In contrast with previous works on this topic, essentially full conversion of the polyamic acid to polyimide was attained by heating at relatively low temperatures (around 160 °C). These copolyimides undergo an increase of phase separation between the PEO part and the polyimide one after a thermal annealing. This phase separation increases gas separation properties of membranes made up of these copolymers. An exhaustive study of polymer properties as a function of the thermal treatment has been carried out in order to figure out the origin of this behavior. The analysis performed included TGA, DSC, SAXS and mechanical testing. The polymers studied in this paper have medium thermal stability. In fact, degradation of the polyether chain under nitrogen takes place at temperatures above 300 °C. However, their thermal stabilities were much lower under oxidant atmosphere., We are indebted to the Spanish Junta de Castilla León for their financing of this work through the GR-18 Excelence Group Action and to the Ministry of Science and Innovation in Spain for their economic support of the work (MAT2008-00619/MAT). A. Tena thanks CSIC for the predoctoral JAE fellowship received to carry out this work. Authors also acknowledge financial support from the programme CONSOLIDER, project Multicat.

A series of partially pyrolyzed membranes ( PPMs ) were prepared from a copolyimide having carboxylic acid pendant groups ( PIA ). The effect of the final pyrolysis temperature (425, 450 and 475 °C) on the gas separation properties was investigated and compared with those of PIA . The thermal treatments caused a progressive removal of the carboxylic acid pendant groups of PIA and a simultaneous increase of the fractional free volume of the PPMs . Thus, it was found that the permeability coefficients of PPMs were higher than that of PIA , between 6.5 and 25 times higher, depending on the gas tested and the final pyrolysis temperature, while the selectivity slightly decreased. All PPMs were attractive materials to separate CO 2 from CH 4 since were inside the commercially interesting region and are close to the present Robeson trade-off limit line. The pyrolysis at 475 °C yielded the PPM with the best performance: CO 2 /CH 4 selectivity of 47 and CO 2 permeability close to 95 barrers.

Herein, mixed matrix membranes including alumina particles whose surfaces have been differently modified have been made and characterized. The polymeric matrix is a fluorinated polyimide, 6FDA-6FpDA, whereas the inorganic constituent parts are neat, silanized or poly-vinyl-pirrolidone-coated nanometric γ-Al 2 O 3 particles of 40 nm in diameter, which have been added in an approximated percentage of a 12% w/w. All the modified or unmodified added particles lead to similar improvements in the permselectivity of the gas pairs studied. Only in the case of the O 2 /N 2 pair the increase in selectivity for the silanized particles is not as effective as the observed permeability enhancement for the uncoated and PVP-coated particles. In case of CO 2 /CH 4 , the 1991 Robeson's upper bond line is overpassed. The characteristics of the permselectivity improvement for the different inorganic particles have been analyzed in terms of the properties of the particle–polymer interfacial properties.

Producción Científica, In our previous works, it was observed a clear relationship between the structure and the properties for different copoly(ether-imide)s, besides a good relation was found between SAXS characterization and permeability results. Here, a series of aliphatic aromatic copoly( ether-imide)s, based on an aromatic diamine (ODA), a diamine terminated poly(ethylene oxide) (PEO2000) of a molecular weight of 2000 g/mol and different aromatic dianhydrides (BPDA, BKDA (or BTDA) and PMDA) has been synthesized and characterized. The permeability for O2, N2, CO2 and CH4, increased with the rigidity of the monomers (BKDA < BPDA < PMDA), with the amount of PEO2000 in the copolymers, as well as with the increase in the temperature of treatment of the films. In this case, it was observed that when the proportion of PEO in the copolymer exceeded 50%, the permeability was similar for all samples, and the aromatic portion had no significant influence. Attending to glass transition temperature, Tg, of the aliphatic part, to its melting temperature, Tm, and to its crystallinity, segregation was better for more rigid dianhydrides at lower temperatures of treatment. Higher dianhydride rigidity produced better mechanical properties that were good but decreased a little bit when the percentage of PEO in the samples increased. Good permselectivity compromises were attained for the CO2/N2 separation. This work gives indications on how to design advanced materials for this separation with the increasing possibilities of controlled structure and properties., Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13)

Producción Científica, Poly(o-acyloxyamide)s (PORAs) derived from a poly(o-hydroxyamide) from 2,2′-bis(3-amino-4-hydroxyphenyl)- hexafluoropropane (APAF) diamine, APAF−POHA, have been synthesized and evaluated as gas separation materials. PORAs were synthesized from poly(o-hydroxyamide)s by derivatization of the free OH group with an aliphatic acid dichloride or dianhydride that allowed the introduction of acetyl or pivaloyl groups on their structure. All of them showed low−medium thermal stability due to a degradation of the amide moieties, and most of them (those synthesized from isophthaloyl dichloride (IPC), 2,2′-bis(4-carboxyphenyl) hexafluoropropane dichloride (6FC), and 4,4′-dicarboxydiphenylsulfone dichloride (DPSC)) showed good mechanical properties. The poly(o-acyloxyamide)s synthesized have shown good permselectivities for He/N2 and He/CH4 separations and very good permeability−selectivity balance for He/CO2 separation. The acetyl PORAs showed better permeability versus selectivity balances than the pivaloyl ones. Moreover, selectivity increased while permeability decreased in the sequence 6F-APAF > IP-APAF > DPS-APAF. Intersegmental distances, d-spacing, were shown to decrease along this sequence, obtaining a nice correlation between permeability and d-spacing. For the He/N2 and the He/CH4 pairs of gases, the best permeability−selectivity values are obtained for 6F-APAF-Ac with a He permeability of 33 barrer and selectivities of 84 and 106, respectively. DPS-APAF-Ac gives a He permeability of 13 barrer and a selectivity of 21 for the He/CO2 separation., Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13)

Polyethylene oxide (PEO)-based polymers containing long PEO chains are one of the best materials for postcombustion processes, attending to their separation properties. Optimal conditions for the application of the membrane separation module are immediately after elimination of water vapor, NO x , SO2, and dust particles, where the temperature of the gas is between 25 and 40 °C. Materials with high contents and longer length of PEO are the ideal candidates for the application in terms of properties. Unfortunately, these materials are normally not applicable due to, at these temperatures, the high crystallinity of PEO chains, which leads to poor gas separation properties. Here, by electron beam irradiation, it has been possible to eliminate or substantially reduce the crystallinity of poly(ether-imide)s with high PEO content, which is confirmed by the positive effect in the separation properties. Optimal dosage to eliminate the crystallinity and to maximize permeability has been investigated.

Se ha realizado el estudio de sistemas de copolieter-imidas, que tienen la capacidad de segregar en fases para su aplicación en el campo de la separación de gases, concretamente en la separación CO2/N2. Se realizó el análisis de la influencia en las propiedades de los copolímeros de: su composición (utilizando diferentes dianhidridos, diaminas y poliéteres); y su estructura (variando la longitud y cantidad de polieter); y por último se ha desarrollado un modelo predictivo de propiedades de permeación. La permabilidad al CO2 se vió favorecida con una mejora en la segregación de fases, y esto ocurría cuando aumentabamos la rigidez de los monómeros, la longitud o el contenido en poliéter; sin efecto en la selectividad . A porcentajes elevados de polieter, la fase aromática no tenía influencia en las propiedades de separación. El modelo EMT predijo todas estas situaciones sin necesidad de conocer detalles estructurales de los copolimeros sintetizados., Departamento de Física Aplicada

Copoly(ether imide)s formed by the reaction of an aromatic dianhydride (BPDA), an aromatic diamine (ODA or BNZ), and ¿,¿-bis(2-aminopropyl polypropylene oxide)s with molecular weights of 2000 and 4000 g/mol were obtained, characterized, and studied as gas separation membranes. All of the copoly(ether imide)s studied showed a low imidization temperature, well below 200 °C. They also underwent a phase segregation process, as confirmed by SAXS, when they were thermally treated. The segregation was found to increase permeability without any significant decrease of selectivity for almost all of the gas pairs studied (O2/N2, CO2/CH4, and CO2/N2). For the CH4/N2 pair, a strong increase in selectivity was obtained upon segregation, along with a rising permeability. This excellent gas productivity for the mixture CH4/N2 is probably due to a combined effect of a specific interaction and an increase in solubility of CH4 in the soft segregated domains of the copolymer. Methane permeabilities over 20 barrer and CH4/N2 selectivities close to 4.2 for an applied pressure of 1 bar were attained. The changes in permselectivity with permeation temperature were observed to follow an Arrhenius correlation, which adds a certain tunable permeability versus selectivity to these materials. Thus, it is possible to attain high selectivities (for relatively low temperatures) or high permeabilities (for comparatively high temperatures). The proportion of PPO in the final polymer has a significant influence on the segregation extent and domains, so that both the selectivity and permeability improved when the proportion of polyether in the final polymer was high. The mechanical properties were good for all of the proportions and/or densities tested. All of the copolymers studied showed a high resistance to plasticization and to the action of solvents and aggressive media. The high permselectivities and resistance to plasticization and solvents suggest that the membranes obtained could be advantageously used in natural gas extraction and purification.

In this work, the synthesis of block copolyimides, having an analogous composition, derived from the reaction of an aromatic dianhydride (BPDA) with a mixture of both an aromatic diamine (ODA) and an aliphatic diamine with poly(propylene-oxyde)s moieties (PPO-4000) has been carried out.In particular the mass fraction of PPO can be varied from 17% up to 67%, obtaining a wide range of physical as well as permselectivity properties. CO2 solubility measurements were performed on different block copolymers, in isothermal conditions in a pressure decay equipment which works up to 20 bar. The effect of PPO content, as well as temperature of thermal treatment experienced by the samples prior to characterization, on the CO2 solubility at different temperatures (from 25 to 65°C) and pressures (up to 20 bar) has been investigated.