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Prof. Dr. María Desamparados Ribes Greus
Institute of Technology of Materials (ITM), Universitat Politècnica de València (UPV), Camí de Vera, s/n, 46022 Valencia, Spain

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0 Energy Storage
0 Self-healing polymers
0 Electroactive Polymers
0 biomedical polymers
0 Smart and biodegradable packaging

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Journal article
Published: 28 June 2021 in Energy
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Cotton seed was submitted to fast pyrolysis in a fixed bed reactor and the liquid and solid products were characterized applying several techniques. The detailed chemical composition of the bio-oil was investigated using GC × GC/TOFMS combined with software tools and retention index. A total of 257 compounds were tentatively identified with 168 were confirmed by LTPRI. The most abundant compounds identified in the cotton seed bio-oil were nitrogenous (56 compounds) and phenolic (42 compounds) what distinguishes this bio oil from others, produced from various sources of biomass. The higher heating values of cotton seed and bio-oil were 19.34 MJ kg −1 and 34.25 MJ kg −1 respectively and demonstrating the feasibility of the use of cotton seed in its natural form for energy generation or as a secondary source once a bio-oil with these characteristics would be a suitable candidate for use in boilers for heating purposes or chemical extraction. The biochar had a significant carbon content and a high heating value (22.12 MJ kg −1), making it attractive for fuel applications. The activation methods used were able to improve the physical and chemical characteristics of the biochar, as demonstrated by methylene blue adsorption tests. The maximum adsorption capacity of NaOH-activated biochar was 23.82 mg g −1 while that of K2CO3-activated biochar was 332.40 mg g −1.

ACS Style

Carmem T. Primaz; Amparo Ribes-Greus; Rosângela A. Jacques. Valorization of cotton residues for production of bio-oil and engineered biochar. Energy 2021, 235, 121363 .

AMA Style

Carmem T. Primaz, Amparo Ribes-Greus, Rosângela A. Jacques. Valorization of cotton residues for production of bio-oil and engineered biochar. Energy. 2021; 235 ():121363.

Chicago/Turabian Style

Carmem T. Primaz; Amparo Ribes-Greus; Rosângela A. Jacques. 2021. "Valorization of cotton residues for production of bio-oil and engineered biochar." Energy 235, no. : 121363.

Journal article
Published: 13 June 2021 in Polymers
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The macromolecular dynamics of dendronized copolymer membranes (PECHs), obtained by chemical modification of poly(epichlorohydrin) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, was investigated. In response to a thermal treatment during membrane preparation, these copolymers show an ability to change their shape, achieve orientation, and slightly crystallize, which was also observed by CP-MAS NMR, XRD, and DSC. The phenomenon was deeply analyzed by dielectric thermal analysis. The dielectric spectra show the influence of several factors such as the number of dendritic side groups, the orientation, their self-assembling dendrons, and the molecular mobility. The dielectric spectra present a sub-Tg dielectric relaxation, labelled as γ, associated with the mobility of the benzyloxy substituent of the dendritic group. This mobility is not related to the percentage of these lateral chains but is somewhat hindered by the orientation of the dendritic groups. Unlike other less complex polymers, the crystallization was dismantled before the appearance of the glass transition (αTg). Only after that, clearing transition (αClear) can be observed. The PECHs were flexible and offered a high free volume, despite presenting a high degree of modifications. However, the molecular mobility is not independent in each phase and the self-assembling dendrons can be eventually fine-tuned according to the percentage of grafted groups.

ACS Style

R. Teruel-Juanes; B. Pascual-Jose; R. Graf; J. Reina; M. Giamberini; A. Ribes-Greus. Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers. Polymers 2021, 13, 1961 .

AMA Style

R. Teruel-Juanes, B. Pascual-Jose, R. Graf, J. Reina, M. Giamberini, A. Ribes-Greus. Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers. Polymers. 2021; 13 (12):1961.

Chicago/Turabian Style

R. Teruel-Juanes; B. Pascual-Jose; R. Graf; J. Reina; M. Giamberini; A. Ribes-Greus. 2021. "Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers." Polymers 13, no. 12: 1961.

Journal article
Published: 01 April 2021 in Polymer
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In the present study, the dielectric properties of both neat and plasticized polylactide submitted to repeated extrusion and injection processes to simulate recycling were analysed. The dielectric relaxation spectrum, consisting of β and α relaxation, revealed the relevance of both acryl-PEG based plasticization and thermo-mechanical degradation induced by repeated extrusion and grinding-injection reprocessing cycles on polylactide (PLA). The β-relaxation has its origin in the intramolecular local motions of pendant groups of the PLA backbone, while the α-relaxation is representative of the intermolecular large-scale segmental motions of the PLA backbone. The addition of acryl-PEG to PLA (pPLA) induced an increment in the apparent activation energies and temperatures of the β-relaxation due to the different nature of the acryl-pendant group in pPLA. Moreover, the crystallization rate of pPLA was much faster compared to that of neat PLA, which hindered the movements of the acryl-pendant group, thus requiring more energy to orient the dipoles. The plasticizing effect of acryl-PEG effectively aids the large-scale motions associated to the glass transition, which are the origin of the α-relaxation. The effect of reprocessing in PLA is less relevant than the addition of the acryl-PEG plasticizer, in terms of dielectric behaviour. With increasing the number of processing cycles, the crystallization rate of PLA gradually increased, but the permittivity was still much lower than that of pPLA, for which crystallinity remained constant. Nonetheless, for the case of the α-relaxation of pPLA, the rearrangements produced by chain scission induced an enhancement of the thermal activation of the orientation of the dipoles but reduced the dynamic fragility and increased the embrittlement of pPLA after reprocessing. These differences found in the relaxation spectrum and the molecular dynamics in the environment of the glass transition for PLA and pPLA, together with the embrittlement of pPLA after reprocessing, is what will determine the final use of one or the other recycled polymer.

ACS Style

B. Pascual-Jose; J.D. Badia; A. Múgica; Frédéric Addiego; Alejandro J. Müller; A. Ribes-Greus. Analysis of plasticization and reprocessing effects on the segmental cooperativity of polylactide by dielectric thermal spectroscopy. Polymer 2021, 223, 123701 .

AMA Style

B. Pascual-Jose, J.D. Badia, A. Múgica, Frédéric Addiego, Alejandro J. Müller, A. Ribes-Greus. Analysis of plasticization and reprocessing effects on the segmental cooperativity of polylactide by dielectric thermal spectroscopy. Polymer. 2021; 223 ():123701.

Chicago/Turabian Style

B. Pascual-Jose; J.D. Badia; A. Múgica; Frédéric Addiego; Alejandro J. Müller; A. Ribes-Greus. 2021. "Analysis of plasticization and reprocessing effects on the segmental cooperativity of polylactide by dielectric thermal spectroscopy." Polymer 223, no. : 123701.

Journal article
Published: 28 March 2021 in Polymers
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Unoriented and oriented membranes based on dendronized polymers and copolymers obtained by chemical modification of poly[2-(aziridin-1-yl) ethanol] (PAZE) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy]benzoate were considered. DSC, XRD, CP-MAS NMR and DETA, contribute to characterize the tendency to crystallize, the molecular mobility of the benzyloxy substituent, the dendritic liquid crystalline group and the clearing transition. The orientation of the mesogenic chain somewhat hindered this molecular motion, especially in the full substituted PAZE. The fragility, free volume and thermal expansion coefficients of these membranes near the glass transition are related to the orientation and the addition of the dendritic groups. PAZE-based membranes combine both order and mobility on a supramolecular and macroscopic level, controlled by the dendritic group and the thermal orientation, and open the possibility of preparing membranes with proper channel mobility that promotes selective ionic transport.

ACS Style

Roberto Teruel-Juanes; Krzysztof Bogdanowicz; Jose Badia; Victor Sáenz de Juano-Arbona; Robert Graf; Jose Reina; Marta Giamberini; Amparo Ribes-Greus. Molecular Mobility in Oriented and Unoriented Membranes Based on Poly[2-(Aziridin-1-yl)ethanol]. Polymers 2021, 13, 1060 .

AMA Style

Roberto Teruel-Juanes, Krzysztof Bogdanowicz, Jose Badia, Victor Sáenz de Juano-Arbona, Robert Graf, Jose Reina, Marta Giamberini, Amparo Ribes-Greus. Molecular Mobility in Oriented and Unoriented Membranes Based on Poly[2-(Aziridin-1-yl)ethanol]. Polymers. 2021; 13 (7):1060.

Chicago/Turabian Style

Roberto Teruel-Juanes; Krzysztof Bogdanowicz; Jose Badia; Victor Sáenz de Juano-Arbona; Robert Graf; Jose Reina; Marta Giamberini; Amparo Ribes-Greus. 2021. "Molecular Mobility in Oriented and Unoriented Membranes Based on Poly[2-(Aziridin-1-yl)ethanol]." Polymers 13, no. 7: 1060.

Article
Published: 07 March 2021 in Journal of Polymer Science
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A set of styrene‐ethylene‐butylene‐styrene triblock copolymer (SEBS) membranes with 10 or 25 wt% divinyl‐benzene (DVB) as a crosslinking agent were prepared and validated. Physicochemical characterization revealed suitable hydrolytic and thermal stability of photo‐crosslinked membranes containing 25 wt% DVB and post‐sulfonated. These compositions were evaluated in H2/O2 single cells, and electrical and proton conductivities were furtherly assessed. The membranes with the milder post‐sulfonation showed greater proton conductivity than those with excessive sulfonation. In terms of electrical conductivity, a universal power law was applied, and the values obtained were low enough for being used as polyelectrolytes. At the analyzed temperatures, the charge transport process follows a long‐range pathway or vehicular model. Finally, fuel cell performance revealed the best behavior for the membrane with 25 wt% DVB, photo‐crosslinked during 30 min and mild sulfonated, with a promising power density of 526 mW·cm−2. Overall, the results obtained highlight the promising fuel cell performance of these cost‐effective triblock copolymer‐based membranes and indicate that higher sulfonation does not necessarily imply better power density.

ACS Style

Roberto Teruel‐Juanes; Carmen del Río; Oscar Gil‐Castell; Carmem Primaz; Amparo Ribes‐Greus. Triblock SEBS / DVB crosslinked and sulfonated membranes: Fuel cell performance and conductivity. Journal of Polymer Science 2021, 138, 50671 .

AMA Style

Roberto Teruel‐Juanes, Carmen del Río, Oscar Gil‐Castell, Carmem Primaz, Amparo Ribes‐Greus. Triblock SEBS / DVB crosslinked and sulfonated membranes: Fuel cell performance and conductivity. Journal of Polymer Science. 2021; 138 (28):50671.

Chicago/Turabian Style

Roberto Teruel‐Juanes; Carmen del Río; Oscar Gil‐Castell; Carmem Primaz; Amparo Ribes‐Greus. 2021. "Triblock SEBS / DVB crosslinked and sulfonated membranes: Fuel cell performance and conductivity." Journal of Polymer Science 138, no. 28: 50671.

Journal article
Published: 21 October 2020 in Polymer Degradation and Stability
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The influence of the addition of graphene nanoplatelets (GNPs) on the intra/inter – molecular segmental motions of poly(ethylene-co-vinyl alcohol) (EVOH) was assessed by means of dielectric thermal analysis (DETA). The relaxation spectra were studied in terms of the dielectric permittivity (ε′) and the dielectric loss tangent (tan δ) at wide ranges of frequency (from 10−2 to 107 Hz) and temperature (from -150 to 140 °C). Two relaxation zones were disthinguished. Below the glass transition temperature (Tg), two β-relaxations were observed, which are characteristic local modes of mobility of the EVOH side groups, and related to the influence of the different surroundings of ethylene or vinyl alcohol units. At higher temperatures, the dielectric α-relaxation in the vicinities of the glass transition of EVOH was determined. The thermal activation of the β-relaxations was explained by an Arrhenius model, and showed activation energies (Ea) around 55 and 80 kJ·mol−1. The α-relaxation was explained by the Vogel-Fulcher-Tammann-Hesse (VFTH) model. The study of the segmental dynamics showed an increase in the dynamic fragility parameters with the addition of GNPs. The permittivity was increased at preferential concentrations of GNPs. In particular, the addition of GNPs up to 0.5 wt% increased the dielectric permittivity of the electrospun EVOH/GNPs nanocomposite fibers, specially at low frequencies.

ACS Style

J.D. Badia; R. Teruel-Juanes; Y. Echegoyen; S. Torres-Giner; J.M. Lagarón; A. Ribes-Greus. Effect of graphene nanoplatelets on the dielectric permittivity and segmental motions of electrospun poly(ethylene-co-vinyl alcohol) nanofibers. Polymer Degradation and Stability 2020, 183, 109404 .

AMA Style

J.D. Badia, R. Teruel-Juanes, Y. Echegoyen, S. Torres-Giner, J.M. Lagarón, A. Ribes-Greus. Effect of graphene nanoplatelets on the dielectric permittivity and segmental motions of electrospun poly(ethylene-co-vinyl alcohol) nanofibers. Polymer Degradation and Stability. 2020; 183 ():109404.

Chicago/Turabian Style

J.D. Badia; R. Teruel-Juanes; Y. Echegoyen; S. Torres-Giner; J.M. Lagarón; A. Ribes-Greus. 2020. "Effect of graphene nanoplatelets on the dielectric permittivity and segmental motions of electrospun poly(ethylene-co-vinyl alcohol) nanofibers." Polymer Degradation and Stability 183, no. : 109404.

Journal article
Published: 26 August 2020 in Reactive and Functional Polymers
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A series of UV photocrosslinked and post-sulfonated membranes based on blends of styrene-ethylene-butylene-styrene triblock copolymer (SEBS) and divinylbenzene (DVB) were considered for the preparation of electrolytes for proton exchange membrane fuel cell (PEMFC) applications. Macromolecular dynamics of SEBS and SEBS-DVB membranes below and above the Tg, were analysed using dielectric thermal analysis (DETA). A sub-Tg intramolecular non-cooperative dielectric relaxation and two main relaxations, corresponding to the glass transitions of ethylene-butylene (EB) and styrene (S) blocks, were identified in the dielectric relaxation spectrum. The photocrosslinking and post-sulfonation processes affect to the entire dielectric relaxation spectrum, the apparent activation energy and the fragilities of both styrene (S) and ethylene-butylene (EB) blocks. Understanding the restrictions on the segmental mobility at low and high scale caused by both photocrosslinking and subsequent sulfonation is basic to provide an approach to ionic diffusivities. A correlation between relaxations processes and the performance of these membranes in H2/O2 – PEM single cells allows to estimate the behaviour of these membranes and to reengineer them, depending on the modification of the desired cell performance.

ACS Style

R. Teruel-Juanes; B. Pascual-Jose; C. del Río; O. García; A. Ribes-Greus. Dielectric analysis of photocrosslinked and post-sulfonated styrene-ethylene-butylene-styrene block copolymer based membranes. Reactive and Functional Polymers 2020, 155, 104715 .

AMA Style

R. Teruel-Juanes, B. Pascual-Jose, C. del Río, O. García, A. Ribes-Greus. Dielectric analysis of photocrosslinked and post-sulfonated styrene-ethylene-butylene-styrene block copolymer based membranes. Reactive and Functional Polymers. 2020; 155 ():104715.

Chicago/Turabian Style

R. Teruel-Juanes; B. Pascual-Jose; C. del Río; O. García; A. Ribes-Greus. 2020. "Dielectric analysis of photocrosslinked and post-sulfonated styrene-ethylene-butylene-styrene block copolymer based membranes." Reactive and Functional Polymers 155, no. : 104715.

Journal article
Published: 03 August 2020 in Polymer Degradation and Stability
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The extended use of polymers from renewable resources such as aliphatic polyesters or polyhydroxyalkanoates boosted the necessity to understand their behaviour in an end-of-life scenario. Although they can be degraded in reasonable shorter times than traditional polymers, understanding the degradation mechanisms under dissimilar conditions will contribute to further developments in this field. This work aimed to study the effect of temperature and substrate in the degradation of polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) in a simulated laboratory scale to ascertain their contribution, separately or in combination. For this purpose, nine parallel degradation assays were performed by means of the combination of mesophilic (25 °C), thermophilic (58 °C) and hyperthermophilic (80 °C) temperatures with enriched synthetic medium, compost and standardised soil substrates. Although the analysis of the surface morphology, the thermal properties and the thermo-oxidative stability revealed changes as a function of time, the evaluation of the molar mass allowed for a more precise determination of the degradation. In general, chain scission was perceived in all cases as a function of time. The effect of temperature was critical, significantly more important than the effect of the substrate, which showed a less significant contribution, especially in terms of molar mass reduction. While for the PLA, biodegradation at 58 °C and thermal degradation at 80 °C resulted in similar consequences, for the PHBH the hyperthermophilic temperature of 80 °C was the most severe condition, regardless of the substrate. From a technological perspective, it may be highlighted that biodegradation at 58 °C may be the most cost-effective condition due to the lower energy supply required and the valuable contribution of the microorganisms.

ACS Style

O. Gil-Castell; R. Andres-Puche; E. Dominguez; E. Verdejo; L. Monreal; A. Ribes-Greus. Influence of substrate and temperature on the biodegradation of polyester-based materials: Polylactide and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as model cases. Polymer Degradation and Stability 2020, 180, 109288 .

AMA Style

O. Gil-Castell, R. Andres-Puche, E. Dominguez, E. Verdejo, L. Monreal, A. Ribes-Greus. Influence of substrate and temperature on the biodegradation of polyester-based materials: Polylactide and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as model cases. Polymer Degradation and Stability. 2020; 180 ():109288.

Chicago/Turabian Style

O. Gil-Castell; R. Andres-Puche; E. Dominguez; E. Verdejo; L. Monreal; A. Ribes-Greus. 2020. "Influence of substrate and temperature on the biodegradation of polyester-based materials: Polylactide and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as model cases." Polymer Degradation and Stability 180, no. : 109288.

Review article
Published: 29 July 2020 in Polymer Testing
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Composite membranes based on poly(vinyl alcohol) (PVA) and graphene oxide (GO) were prepared by solution-casting method to be used as proton exchange membranes (PEMs) in fuel cell (FC) applications. Bisulfonation was employed as a strategy to enhance the proton conductivity of these membranes. First, a direct sulfonation of the polymer matrix was accomplished by intra-sulfonation of the polymer matrix with propane sultone, followed by the inter-sulfonation of the polymer chains using sulfosuccinic acid (SSA) as a crosslinking agent. Furthermore, the addition of graphene oxide (GO) as inorganic filler was also evaluated to enhance the proton-conducting of the composite membranes. These membranes were fully characterized by scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and tensile tests. Besides, the proton conductivity of these membranes in a fully hydrated state was also analyzed by electrochemical impedance spectroscopy (EIS). The effect of the intra- and inter-sulfonation of the polymer matrix on the structural, morphological, thermal and mechanical properties of the membranes were determined. Increasing the density of sulfonic acid groups in the membranes resulted in a trade-off between a better proton conductivity (improving from 0.26 to 1.00 mS/cm) and a decreased thermal and mechanical stability. In contrast, the incorporation of GO nanoparticles into the polymer matrix improved the thermal and mechanical stability of both bisulfonated composite membranes. The proton conductivity appreciably increased by the combination of bisulfonation and introduction of GO nanoparticles into the polymer matrix. The sPVA/30SSA/GO composite membrane exhibited a proton conductivity of 1.95 mS/cm at 25 °C. The combination of the GO nanoparticles with the chemical bisulfonation approach of PVA allows thus assembling promising proton exchange membrane candidates for fuel cell applications.

ACS Style

S.C. Sánchez-Ballester; V. Soria; G. Rydzek; K. Ariga; A. Ribes-Greus. Synthesis and characterization of bisulfonated poly(vinyl alcohol)/graphene oxide composite membranes with improved proton exchange capabilities. Polymer Testing 2020, 91, 106752 .

AMA Style

S.C. Sánchez-Ballester, V. Soria, G. Rydzek, K. Ariga, A. Ribes-Greus. Synthesis and characterization of bisulfonated poly(vinyl alcohol)/graphene oxide composite membranes with improved proton exchange capabilities. Polymer Testing. 2020; 91 ():106752.

Chicago/Turabian Style

S.C. Sánchez-Ballester; V. Soria; G. Rydzek; K. Ariga; A. Ribes-Greus. 2020. "Synthesis and characterization of bisulfonated poly(vinyl alcohol)/graphene oxide composite membranes with improved proton exchange capabilities." Polymer Testing 91, no. : 106752.

Full paper
Published: 24 April 2020 in Energy Technology
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The use nanotechnology along with the consideration of a functionalization and stabilization approach to the poly(vinyl alcohol) (PVA) was considered useful for the preparation of cost‐effective polyelectrolyte membranes. A set of nanocomposite and crosslinked membranes based in PVA/SSA/GO were prepared and analyzed as polyelectrolytes in direct methanol fuel cells (DMFCs). The crosslinking and sulfonation by the use of sulfosuccinic acid (SSA) enhanced the stability and increased the proton conducting sites in the PVA structure. The presence of graphene oxide (GO) augmented the stability, remarkably decreased the methanol crossover and enhanced power density curves. An optimum value for proton conductivity was found for the 0.50%wt of GO proportion, which decreased to higher concentrations of GO. Given the power density curve dependency on both the proton conductivity and the crossover reduction, the performance of these membranes as polyelectrolytes in DMFCs is strictly related to the balance between both factors. Therefore, a proportion of GO of 0.75%wt may assure suitable proton conductivity 3 mS·cm−1 and high resistance to methanol permeability, reaching promising power density of 16 mW·cm−2 with lower hydration levels. This article is protected by copyright. All rights reserved.

ACS Style

Oscar Gil-Castell; Óscar Santiago; Borja Pascual-Jose; Emilio Navarro; Teresa J. Leo; Amparo Ribes-Greus. Performance of Sulfonated Poly(Vinyl Alcohol)/Graphene Oxide Polyelectrolytes for Direct Methanol Fuel Cells. Energy Technology 2020, 8, 1 .

AMA Style

Oscar Gil-Castell, Óscar Santiago, Borja Pascual-Jose, Emilio Navarro, Teresa J. Leo, Amparo Ribes-Greus. Performance of Sulfonated Poly(Vinyl Alcohol)/Graphene Oxide Polyelectrolytes for Direct Methanol Fuel Cells. Energy Technology. 2020; 8 (7):1.

Chicago/Turabian Style

Oscar Gil-Castell; Óscar Santiago; Borja Pascual-Jose; Emilio Navarro; Teresa J. Leo; Amparo Ribes-Greus. 2020. "Performance of Sulfonated Poly(Vinyl Alcohol)/Graphene Oxide Polyelectrolytes for Direct Methanol Fuel Cells." Energy Technology 8, no. 7: 1.

Journal article
Published: 17 March 2020 in Molecules
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Encapsulated fat-soluble powders containing vitamin A (VA) and E (VE) were prepared as a feasible additive for extruded feed products. The effect of the encapsulating agents (Capsul-CAP®, sodium caseinate-SC) in combination with Tween 80 (TW) as an emulsifier and maltodextrin (MD) as a wall material on the physicochemical properties of emulsions and powders was evaluated. First, nanoemulsions containing MD:CAP:TW:VA/VE and MD:SC:TW:VA/VE were prepared and characterized. Then, powders were obtained by means of spray-drying and analyzed in terms of the product yield, encapsulation efficiency, moisture content, porosity, surface morphology, chemical structure, and thermal properties and thermo-oxidative/thermal stability. Results showed that although nanoemulsions were obtained for all the compositions, homogeneous microcapsules were found after the drying process. High product yield and encapsulation efficiency were obtained, and the presence of the vitamins was corroborated. The characteristics of the powders were mainly influenced by the encapsulating agent used and also by the type of vitamin. In general, the microcapsules remained thermally stable up to 170 °C and, therefore, the proposed encapsulation systems for vitamins A and E were suitable for the preparation of additives for the feed manufacturing through the extrusion process.

ACS Style

Javiera Mujica-Álvarez; O. Gil-Castell; Pabla A. Barra; A. Ribes-Greus; Rubén Bustos; Mirko Faccini; Silvia Matiacevich. Encapsulation of Vitamins A and E as Spray-Dried Additives for the Feed Industry. Molecules 2020, 25, 1357 .

AMA Style

Javiera Mujica-Álvarez, O. Gil-Castell, Pabla A. Barra, A. Ribes-Greus, Rubén Bustos, Mirko Faccini, Silvia Matiacevich. Encapsulation of Vitamins A and E as Spray-Dried Additives for the Feed Industry. Molecules. 2020; 25 (6):1357.

Chicago/Turabian Style

Javiera Mujica-Álvarez; O. Gil-Castell; Pabla A. Barra; A. Ribes-Greus; Rubén Bustos; Mirko Faccini; Silvia Matiacevich. 2020. "Encapsulation of Vitamins A and E as Spray-Dried Additives for the Feed Industry." Molecules 25, no. 6: 1357.

Journal article
Published: 01 January 2020 in Journal of Renewable Materials
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Composite polymer electrolyte membranes were prepared with poly (vinyl alcohol) (PVA). Two different molecular weight (Mw), 67·103 and 130·103 g·mol−1 were selected, cross-linked with sulfosuccinic acid (SSA) and doped graphene oxide (GO). The effects on the membranes obtained from these polymers were characterized in order to evaluate the fuel cell performance. Electron microscopy showed a proper nanoparticle distribution in the polymer matrix. The chemical structure was evaluated by Fourier transform infrared spectroscopy. The absence of a crystalline structure and the enhancement on the thermal stability with the addition of 1% of GO was demonstrated by thermal characterization. Total transference number and protonic conductivity were correlated to the performance of a hydrogen fuel cell. Overall, a power increase in the composite membranes with lower molecular weight was observed. Shorter polymer chains may improve protonic conductivity and consequently the fuel cell performance.

ACS Style

C.Gonz醠ez-Guisasola; O. Gil-Castell; R. Teruel-Juanes; A. Ribes-Greus. Influence of the Molecular Weight on PVA/GO Composite Membranes for Fuel Cell Applications. Journal of Renewable Materials 2020, 8, 1171 -1180.

AMA Style

C.Gonz醠ez-Guisasola, O. Gil-Castell, R. Teruel-Juanes, A. Ribes-Greus. Influence of the Molecular Weight on PVA/GO Composite Membranes for Fuel Cell Applications. Journal of Renewable Materials. 2020; 8 (9):1171-1180.

Chicago/Turabian Style

C.Gonz醠ez-Guisasola; O. Gil-Castell; R. Teruel-Juanes; A. Ribes-Greus. 2020. "Influence of the Molecular Weight on PVA/GO Composite Membranes for Fuel Cell Applications." Journal of Renewable Materials 8, no. 9: 1171-1180.

Journal article
Published: 02 December 2019 in Materials
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The curing of composite materials is one of the parameters that most affects their mechanical behavior. The inspection methods used do not always allow a correct characterization of the curing state of the thermosetting resins. In this work, Raman spectroscopy technology is used for measuring the degree of cure. The results are compared with conventional thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscope (SEM). Carbon fiber specimens manufactured with technologies out of autoclave (OoA) have been used, with an epoxy system Prepreg System, SE 84LV. The results obtained with Raman technology show that it is possible to verify the degree of polymerization, and the information is complementary from classical thermal characterization techniques such as TGA and DSC; thus, it is possible to have greater control in curing and improving the quality of the manufactured parts.

ACS Style

Juan A. García-Manrique; Bernabé Marí; Amparo Ribes-Greus; Llúcia Monreal; Roberto Teruel; Llanos Gascón; Juan A. Sans; Júlia Marí Guaita. Study of the Degree of Cure through Thermal Analysis and Raman Spectroscopy in Composite-Forming Processes. Materials 2019, 12, 3991 .

AMA Style

Juan A. García-Manrique, Bernabé Marí, Amparo Ribes-Greus, Llúcia Monreal, Roberto Teruel, Llanos Gascón, Juan A. Sans, Júlia Marí Guaita. Study of the Degree of Cure through Thermal Analysis and Raman Spectroscopy in Composite-Forming Processes. Materials. 2019; 12 (23):3991.

Chicago/Turabian Style

Juan A. García-Manrique; Bernabé Marí; Amparo Ribes-Greus; Llúcia Monreal; Roberto Teruel; Llanos Gascón; Juan A. Sans; Júlia Marí Guaita. 2019. "Study of the Degree of Cure through Thermal Analysis and Raman Spectroscopy in Composite-Forming Processes." Materials 12, no. 23: 3991.

Journal article
Published: 14 October 2019 in Materials Science and Engineering: C
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Nanofibrous scaffolds composed of polycaprolactone (PCL) and gelatin (Ge) were obtained through a hydrolytic assisted electrospinning process. The PCL-to-Ge proportion (100/0 to 20/80), as well as the dissolution time (24, 48, 72, 96, 120 h) into a 1:1 formic/acetic acid solvent before electrospinning were modified to obtain the different samples. A strong influence of these factors on the physicochemical properties of the scaffolds was observed. Higher Ge percentage reduced crystallinity, allowed a uniform morphology and increased water contact angle. The increase in the dissolution time considerably reduced the molar mass and, subsequently, fibre diameter and crystallinity were affected. During in vitro biocompatibility tests, higher cell adhesion and proliferation were found for the 60/40, 50/50 and 40/60 PCL/Ge compositions that was corroborated by MTT assay, fluorescence and microscopy. A weakened structure, more labile to the in vitro degradation in physiologic conditions was found for these compositions with higher dissolution times (72 and 96 h). Particularly, the 40/60 PCL/Ge scaffolds revealed an interesting progressive degradation behaviour as a function of the dissolution time. Moreover, these scaffolds were non-inflammatory, as revealed by the pyrogen test and after the 15-day subcutaneous in vivo implantation in mice. Finally, a reduction of the scar tissue area after infarction was found for the 40/60 PCL/Ge scaffolds electrospun after 72 h implanted in rat hearts. These results are especially interesting and represent a feasible way to avoid undesired inflammatory reactions during the scaffold assimilation.

ACS Style

O. Gil-Castell; J.D. Badia; I. Ontoria-Oviedo; D. Castellano; P. Sepúlveda; A. Ribes-Greus. Polycaprolactone/gelatin-based scaffolds with tailored performance: in vitro and in vivo validation. Materials Science and Engineering: C 2019, 107, 110296 .

AMA Style

O. Gil-Castell, J.D. Badia, I. Ontoria-Oviedo, D. Castellano, P. Sepúlveda, A. Ribes-Greus. Polycaprolactone/gelatin-based scaffolds with tailored performance: in vitro and in vivo validation. Materials Science and Engineering: C. 2019; 107 ():110296.

Chicago/Turabian Style

O. Gil-Castell; J.D. Badia; I. Ontoria-Oviedo; D. Castellano; P. Sepúlveda; A. Ribes-Greus. 2019. "Polycaprolactone/gelatin-based scaffolds with tailored performance: in vitro and in vivo validation." Materials Science and Engineering: C 107, no. : 110296.

Article
Published: 07 August 2019 in Molecules
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The potential of sodium alginate (ALG) and gum arabic (GA) as wall polymers for L-ascorbic acid (AA) encapsulation as a tool for their preservation against the thermo-oxidative degradation was investigated. The influence of such polymers used as wall material on the AA-content, size, encapsulation efficiency, encapsulation yield and thermo-oxidative stability were evaluated. The AA-microparticles were obtained using the spray-drying technique. An experimental Taguchi design was employed to assess the influence of the variables in the encapsulation process. The microparticles morphology and size distribution were characterized by scanning electron microscopy and laser diffraction. The thermal stability of AA microparticles was studied by differential scanning calorimetry and thermogravimetry analysis. This work points out the viability to encapsulate AA using GA and ALG through a spray-drying process. In general, a product yield ranging from 35.1% to 83.2% and an encapsulation efficiency above 90% were reached. Spherical microparticles with a smooth surface were obtained with a mean diameter around 6 μm and 9 μm for the those prepared with GA and ALG, respectively. The thermo-oxidative analysis showed that both polymers allow maintaining AA stable up to 188 °C, which is higher than the traditional processing temperature used in the fish feed industry.

ACS Style

Pabla A. Barra; Katherine Márquez; Oscar Gil-Castell; Javiera Mujica; Amparo Ribes-Greus; Mirko Faccini. Spray-Drying Performance and Thermal Stability of L-Ascorbic Acid Microencapsulated with Sodium Alginate and Gum Arabic. Molecules 2019, 24, 2872 .

AMA Style

Pabla A. Barra, Katherine Márquez, Oscar Gil-Castell, Javiera Mujica, Amparo Ribes-Greus, Mirko Faccini. Spray-Drying Performance and Thermal Stability of L-Ascorbic Acid Microencapsulated with Sodium Alginate and Gum Arabic. Molecules. 2019; 24 (16):2872.

Chicago/Turabian Style

Pabla A. Barra; Katherine Márquez; Oscar Gil-Castell; Javiera Mujica; Amparo Ribes-Greus; Mirko Faccini. 2019. "Spray-Drying Performance and Thermal Stability of L-Ascorbic Acid Microencapsulated with Sodium Alginate and Gum Arabic." Molecules 24, no. 16: 2872.

Preprint
Published: 20 June 2019
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The potential of sodium alginate (ALG) and gum arabic (GA) as wall polymers for L-ascorbic acid (AA) encapsulation as a tool for their preservation against the thermo-oxidative degradation was investigated. The influence of such polymers used as wall material on the AA-content, size, encapsulation efficiency, encapsulation yield and thermo-oxidative stability were evaluated. The AA-microparticles were obtained using the spray-drying technique. An experimental Taguchi design was employed to assess the influence of the variables in the encapsulation process. The microparticles morphology and size distribution were characterized by scanning electron microscopy and laser diffraction. The thermal stability of AA microparticles was studied by differential scanning calorimetry and thermogravimetry analysis. This work points out the viability to encapsulate AA using GA and ALG through a spray-drying process. In general, a product yield ranging from 35.1% to 83.2% and an encapsulation efficiency above 90% was reached. Spherical microparticles with a smooth surface were obtained with a mean diameter around 6 μm and 9 μm for the those prepared with GA and ALG, respectively. The thermo-oxidative analysis showed that both polymers allow maintaining AA stable up to 188 °C, which is higher than the traditional processing temperature used in the fish feed industry.

ACS Style

Pabla Barra; Katherine Márquez; Oscar Gil-Castell; Javiera Mujica; Amparo Ribes-Greus; Mirko Faccini. Spray-Drying Performance and Thermal Stability of L-Ascorbic Acid Microencapsulated with Sodium Alginate and Gum Arabic. 2019, 1 .

AMA Style

Pabla Barra, Katherine Márquez, Oscar Gil-Castell, Javiera Mujica, Amparo Ribes-Greus, Mirko Faccini. Spray-Drying Performance and Thermal Stability of L-Ascorbic Acid Microencapsulated with Sodium Alginate and Gum Arabic. . 2019; ():1.

Chicago/Turabian Style

Pabla Barra; Katherine Márquez; Oscar Gil-Castell; Javiera Mujica; Amparo Ribes-Greus; Mirko Faccini. 2019. "Spray-Drying Performance and Thermal Stability of L-Ascorbic Acid Microencapsulated with Sodium Alginate and Gum Arabic." , no. : 1.

Journal article
Published: 17 June 2019 in Reactive and Functional Polymers
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The preparation polyelectrolytes based on crosslinked poly(vinyl alcohol) (PVA) and chitosan (CS) was considered as a feasible alternative to develop highly functionalised, cost-effective and eco-friendly membranes for proton exchange fuel cell technologies. CS/PVA-based membranes were combined with sulfosuccinic acid (SSA) as crosslinking and sulfonating agent, and glycerol (GL) to promote flexibility and favour their manageability. The chemical structure, the thermo-oxidative behaviour, the ethanol uptake, the electric, the proton conductivity, and the performance in direct ethanol fuel cell (DEFC) were assessed. In general, all the CS/PVA-based polyelectrolytes showed a synergetic increase of thermo-oxidative stability, appropriate absorption and diffusion of ethanol and good proton conductivity, suitable for the typical service conditions of fuel cells. The GL in the membranes reacted with SSA, reduced the ethanol absorption, diffusion coefficient and proton conductivity, but acted as a plasticiser that increased the ductile manageability of the polyelectrolytes to be mounted on the membrane-electrode assembly (MEA). Higher presence of CS and higher the proportion of GL in the polyelectrolyte, improved the material performance in the DEFC. In particular, the crosslinked polyelectrolyte 40CS/PVA/SSA/20GLwith a 40%wt. of CS referred to PVA, and a 20%wt. of GL referred to CS, showed a suitable behaviour in the DEFC test, with a maximum value of power density of 746 mW·cm−2.

ACS Style

O. Gil-Castell; R. Teruel-Juanes; F. Arenga; A.M. Salaberria; M.G. Baschetti; J. Labidi; J.D. Badia; A. Ribes-Greus. Crosslinked chitosan/poly(vinyl alcohol)-based polyelectrolytes for proton exchange membranes. Reactive and Functional Polymers 2019, 142, 213 -222.

AMA Style

O. Gil-Castell, R. Teruel-Juanes, F. Arenga, A.M. Salaberria, M.G. Baschetti, J. Labidi, J.D. Badia, A. Ribes-Greus. Crosslinked chitosan/poly(vinyl alcohol)-based polyelectrolytes for proton exchange membranes. Reactive and Functional Polymers. 2019; 142 ():213-222.

Chicago/Turabian Style

O. Gil-Castell; R. Teruel-Juanes; F. Arenga; A.M. Salaberria; M.G. Baschetti; J. Labidi; J.D. Badia; A. Ribes-Greus. 2019. "Crosslinked chitosan/poly(vinyl alcohol)-based polyelectrolytes for proton exchange membranes." Reactive and Functional Polymers 142, no. : 213-222.

Journal article
Published: 22 May 2019 in Nanomaterials
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The evaluation of the performance of polyesters under in vitro physiologic conditions is essential to design scaffolds with an adequate lifespan for a given application. In this line, the degradation-durability patterns of poly(lactide-co-glycolide) (PLGA), polydioxanone (PDO), polycaprolactone (PCL) and polyhydroxybutyrate (PHB) scaffolds were monitored and compared giving, as a result, a basis for the specific design of scaffolds from short-term to long-term applications. For this purpose, they were immersed in ultra-pure water and phosphate buffer solution (PBS) at 37 °C. The scaffolds for short-time applications were PLGA and PDO, in which the molar mass diminished down to 20% in a 20-30 days lifespan. While PDO developed crystallinity that prevented the geometry of the fibres, those of PLGA coalesced and collapsed. The scaffolds for long-term applications were PCL and PHB, in which the molar mass followed a progressive decrease, reaching values of 10% for PCL and almost 50% for PHB after 650 days of immersion. This resistant pattern was mainly ascribed to the stability of the crystalline domains of the fibres, in which the diameters remained almost unaffected. From the perspective of an adequate balance between the durability and degradation, this study may serve technologists as a reference point to design polyester-based scaffolds for biomedical applications.

ACS Style

Oscar Gil-Castell; José David Badia; Jordi Bou; Amparo Ribes-Greus. Performance of Polyester-Based Electrospun Scaffolds under In Vitro Hydrolytic Conditions: From Short-Term to Long-Term Applications. Nanomaterials 2019, 9, 786 .

AMA Style

Oscar Gil-Castell, José David Badia, Jordi Bou, Amparo Ribes-Greus. Performance of Polyester-Based Electrospun Scaffolds under In Vitro Hydrolytic Conditions: From Short-Term to Long-Term Applications. Nanomaterials. 2019; 9 (5):786.

Chicago/Turabian Style

Oscar Gil-Castell; José David Badia; Jordi Bou; Amparo Ribes-Greus. 2019. "Performance of Polyester-Based Electrospun Scaffolds under In Vitro Hydrolytic Conditions: From Short-Term to Long-Term Applications." Nanomaterials 9, no. 5: 786.

Journal article
Published: 08 March 2019 in Nanomaterials
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Taking advantage of the high functionalization capacity of poly(vinyl alcohol) (PVA), bead-free homogeneous nanofibrous mats were produced. The addition of functional groups by means of grafting strategies such as the sulfonation and the addition of nanoparticles such as graphene oxide (GO) were considered to bring new features to PVA. Two series of sulfonated and nonsulfonated composite nanofibers, with different compositions of GO, were prepared by electrospinning. The use of sulfosuccinic acid (SSA) allowed crosslinked and functionalized mats with controlled size and morphology to be obtained. The functionalization of the main chain of the PVA and the determination of the optimum composition of GO were analyzed in terms of the nanofibrous morphology, the chemical structure, the thermal properties, and conductivity. The crosslinking and the sulfonation treatment decreased the average fiber diameter of the nanofibers, which were electrical insulators regardless of the composition. The addition of small amounts of GO contributed to the retention of humidity, which significantly increased the proton conductivity. Although the single sulfonation of the polymer matrix produced a decrease in the proton conductivity, the combination of the sulfonation, the crosslinking, and the addition of GO enhanced the proton conductivity. The proposed nanofibers can be considered as good candidates for being exploited as valuable components for ionic polyelectrolyte membranes.

ACS Style

Oscar Gil-Castell; Diana Galindo-Alfaro; Soraya Sánchez-Ballester; Roberto Teruel-Juanes; José David Badia; Amparo Ribes-Greus. Crosslinked Sulfonated Poly(vinyl alcohol)/Graphene Oxide Electrospun Nanofibers as Polyelectrolytes. Nanomaterials 2019, 9, 397 .

AMA Style

Oscar Gil-Castell, Diana Galindo-Alfaro, Soraya Sánchez-Ballester, Roberto Teruel-Juanes, José David Badia, Amparo Ribes-Greus. Crosslinked Sulfonated Poly(vinyl alcohol)/Graphene Oxide Electrospun Nanofibers as Polyelectrolytes. Nanomaterials. 2019; 9 (3):397.

Chicago/Turabian Style

Oscar Gil-Castell; Diana Galindo-Alfaro; Soraya Sánchez-Ballester; Roberto Teruel-Juanes; José David Badia; Amparo Ribes-Greus. 2019. "Crosslinked Sulfonated Poly(vinyl alcohol)/Graphene Oxide Electrospun Nanofibers as Polyelectrolytes." Nanomaterials 9, no. 3: 397.

Journal article
Published: 10 January 2019 in European Polymer Journal
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Dielectric Thermal Analysis (DETA) of a series of new thermoset obtained by click chemistry was performed. The new thermosets were obtained by a dual-curing process consisting in a first photochemical thiol-ene, followed by a thermal thiol-epoxy starting from an allyl-terminated hyperbranched poly(ethyleneimine) (HBPEI) and different proportions of diglycidylether of bisphenol A (DGEBA) and the corresponding stoichiometric proportions of pentaerythritol tetrakis (3-mercaptopropionate, PETMP). The dielectric behaviour was obtained experimentally supressing the conductive effects. Two sub-Tg intramolecular non-cooperative γ and β relaxations and an intermolecular cooperative α-relaxation were detected. The γ-relaxation was ascribed to the dipole orientation of the terminal thiol groups. Two γ relaxations γepo and γene were observed, according to the influence of the surroundings. Only thermosets with a content of flexible HBPEI/PETMP domains higher than a 50% w/w showed the γene relaxation at lower temperatures and higher frequencies. The β-relaxation was a non-Johari-Goldstein relaxation, ascribed to the dipole transfer of the linear -CH2-O-(C=O)-CH2-CH2- groups of the thiol constrained in the glassy state. The α-relaxation was ascribed to the long-term segmental movements of the thermosets, occurring during the transition from the glassy to the rubbery stage. A synergic effect of reducing the rigidity and compactness of the thermosets by the reduction of aromatic moieties of the DGEBA/PETMP units, and the increase of the flexibility induced by the addition of HBPEI/PETMP units affected the macromolecular movement of the thermosets.

ACS Style

J.D. Badia; R. Teruel-Juanes; C. Acebo; O. Gil-Castell; A. Serra; A. Ribes-Greus. Dielectric spectroscopy of novel thiol-ene/epoxy thermosets obtained from allyl-modified hyperbranched poly(ethyleneimine) and diglycidylether of bisphenol A. European Polymer Journal 2019, 113, 98 -106.

AMA Style

J.D. Badia, R. Teruel-Juanes, C. Acebo, O. Gil-Castell, A. Serra, A. Ribes-Greus. Dielectric spectroscopy of novel thiol-ene/epoxy thermosets obtained from allyl-modified hyperbranched poly(ethyleneimine) and diglycidylether of bisphenol A. European Polymer Journal. 2019; 113 ():98-106.

Chicago/Turabian Style

J.D. Badia; R. Teruel-Juanes; C. Acebo; O. Gil-Castell; A. Serra; A. Ribes-Greus. 2019. "Dielectric spectroscopy of novel thiol-ene/epoxy thermosets obtained from allyl-modified hyperbranched poly(ethyleneimine) and diglycidylether of bisphenol A." European Polymer Journal 113, no. : 98-106.