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  • Sheets of branched poly(lactic acid) obtained by one-step reactive extrusion-calendering process: physical aging and fracture behavior

     Cailloux, Jonathan; Santana Pérez, Orlando Onofre; Franco Urquiza, Edgar Adrian; Bou Serra, Jorge; Carrasco Alonso, Félix Ángel; Maspoch Ruldua, Maria Lluïsa
    Journal of materials science
    Vol. 49, num. 11, p. 4093-4107
    DOI: 10.1007/s10853-014-8101-y
    Date of publication: 2014-06-01
    Journal article

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    The architectural modifications of a linear poly(D,L-Lactide) acid (PD,L-LA) commercial grade were induced by a one-step reactive extrusion-calendering process using a styrene-glycidyl acrylate copolymer as reactive agent. The melt degradation was counteracted by chain extension and branching reactions, leading to a stabilization of the melt properties and an increase in the molecular weight. For such modified samples [poly(lactic acid) (PLA)-reactive extrusion (REX)], the rate of physical aging at 30 A degrees C was investigated during 1 week in order to simulate industrial storage conditions. Fracture behavior of "de-aged" and "controlled aged" (1 week) samples was investigated using the essential work of fracture (EWF) methodology and the critical tip opening displacement at the crack propagation onset, respectively. These analyses were complemented by digital image correlation analysis and inspection of the fractured surfaces by scanning electronic microscopy. As a result of the architectural modifications, the entanglement network density was increased. Those accounted for a slight decrease in the physical aging rate. Under uniaxial loading, aged reactive extrusion (REX) samples exhibited multiple crazing, leading to a slight increase in strain at break. Nevertheless, as a result of a similar dynamic environment of the entangled polymer coils, de-aged REX samples disclosed similar mechanical properties as compared to their neat counterparts. Regarding de-aged samples, the EWF analysis revealed no changes in the work required for the onset of crack propagation. However, the energy consumed up to the onset of crack propagation of aged PLA-REX samples decreased due to an apparently decreased network extensibility, promoting a premature craze-crack transition.

    The architectural modifications of a linear poly(D,L-Lactide) acid (PD,L-LA) commercial grade were induced by a one-step reactive extrusion-calendering process using a styrene-glycidyl acrylate copolymer as reactive agent. The melt degradation was counteracted by chain extension and branching reactions, leading to a stabilization of the melt properties and an increase in the molecular weight. For such modified samples [poly(lactic acid) (PLA)-reactive extrusion (REX)], the rate of physical aging at 30 A degrees C was investigated during 1 week in order to simulate industrial storage conditions. Fracture behavior of

  • Propiedades mecánicas de residuos de PVC provenientes de cables eléctricos

     Franco Urquiza, Edgar Adrian; Maspoch Ruldua, Maria Lluïsa
    Ingenierías
    Vol. 17, num. 62, p. 29-38
    Date of publication: 2014-01
    Journal article

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    En este trabajo se evaluaron las propiedades mecánicas de desechos de cloruro de polivinilo (PVC) proveniente de cables eléctricos. El residuo contenía 60% de PVC , 30% de polietileno, 7% de goma y 3% de fracción metálica. La fracción metálica de separó de forma manual. La recuperación de PVC se realizó mediante el método de flotación. Se prepararon 6 mezclas de PVC con residuo (R). El PVC y las mezclas se ensayaron a tracción, obteniendo una reducción de la resistencia y la ductilidad al incrementar el contenido de residuo. Esta reducción en las propiedades mecánicas se adjudicó a la heterogeniedad de los componentes de la mezcla.

    En este trabajo se evaluaron las propiedades mecánicas de desechos de cloruro de polivinilo (PVC) proveniente de cables eléctricos. El residuo contenía 60% de PVC , 30% de polietileno, 7% de goma y 3% de fracción metálica. La fracción metálica de separó de forma manual. La recuperación de PVC se realizó mediante el método de flotación. Se prepararon 6 mezclas de PVC con residuo (R). El PVC y las mezclas se ensayaron a tracción, obteniendo una reducción de la resistencia y la ductilidad al incrementar el contenido de residuo. Esta reducción en las propiedades mecánicas se adjudicó a la heterogeniedad de los componentes de la mezcla.

  • Caracterización del comportamiento a fractura de un polipropileno copolímero espumado

     Gómez Monterde, Javier; Franco Urquiza, Edgar Adrian; Sanchez Soto, Miguel Angel; Arencón Osuna, David; Santana Pérez, Orlando Onofre; Docampo, RAmon; Maspoch Ruldua, Maria Lluïsa
    Encuentro del Grupo Español de Fractura
    p. 397-402
    Presentation's date: 2014-04-04
    Presentation of work at congresses

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    En el presente trabajo se ha aplicado el concepto de Trabajo Esencial de Fractura (EWF) a un copolímero etilenopropileno en bloque (EPBC) espumado, cuyas características morfológicas y mecánicas eran conocidas. Las probetas presentaron una propagación de grieta cuasi-estable, con diferentes porcentajes de propagación inestable, lo que pudo relacionarse con el espesor de piel no espumada. Debido a este comportamiento, se llevó a cabo la separación de los parámetros de fractura en iniciación de grieta y propagación, así como el cálculo de la apertura del frente de grieta en el momento de inicio de propagación. Como trabajos futuros se propone la aplicación de modelos de crecimiento y coalescencia de microvacíos, considerando como microvacíos las propias celdillas de la estructura espumada.

    En el presente trabajo se ha aplicado el concepto de Trabajo Esencial de Fractura (EWF) a un copolímero etilenopropileno en bloque (EPBC) espumado, cuyas características morfológicas y mecánicas eran conocidas. Las probetas presentaron una propagación de grieta cuasi-estable, con diferentes porcentajes de propagación inestable, lo que pudo relacionarse con el espesor de piel no espumada. Debido a este comportamiento, se llevó a cabo la separación de los parámetros de fractura en iniciación de grieta y propagación, así como el cálculo de la apertura del frente de grieta en el momento de inicio de propagación. Como trabajos futuros se propone la aplicación de modelos de crecimiento y coalescencia de microvacíos, considerando como microvacíos las propias celdillas de la estructura espumada.

  • Effect of the unidirectional drawing on the thermal and mechanical properties of PLA films with different L -isomer content

     Velázquez Infante, Julio César; Gámez Pérez, José; Franco Urquiza, Edgar Adrian; Santana Pérez, Orlando Onofre; Carrasco, F; Maspoch Ruldua, Maria Lluïsa
    Journal of applied polymer science
    Vol. 127, num. 4, p. 2661-2669
    DOI: 10.1002/app.37546
    Date of publication: 2013-02-15
    Journal article

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    This work simulates the thermoforming process of two different L-isomer content PLA grades (95.6 and 98%), studying the influence on the induced morphology and the variation in the thermal and tensile properties. The thermoforming process was simulated with uniaxial tensile tests performed at different temperatures and strain rates, reporting the tensile behavior before, during, and after the test. The resulting structural changes were analyzed by wide-angle X-ray scattering and Fourier transformed infrared spectroscopy. Thermal characterization was carried out with differential scanning calorimetry and dynamomechanical thermal analysis. The results showed that, regardless the L-isomer content, drawing at 70°C produced a stable mesomorphic phase that showed greater tensile properties than the original films. This mesomorphic phase, indeed, could be reordered into a crystalline structure under mild annealing conditions (5 min/75°C), if compared with those needed for similar amorphous PLA specimens (60 min/120°C), thus providing a processing opportunity for obtaining thermally stable PLA products at temperatures above 100°C.

  • Effect of the strain rate and drawing temperature on the mechanical behavior of EVOH and EVOH composites

     Franco Urquiza, Edgar Adrian; Gámez Pérez, José; Velázquez Infante, Julio César; Santana Pérez, Orlando Onofre; Martinez Benasat, Antonio; Maspoch Ruldua, Maria Lluïsa
    Advances in polymer technology
    Vol. 32, num. 1, p. E287-E296
    DOI: 10.1002/adv.21274
    Date of publication: 2012-02-27
    Journal article

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    The effect of the strain rate and draw temperature on the mechanical behavior of ethylene vinyl alcohol (EVOH) and EVOH composites was analyzed. When EVOH is stretched at moderate strain rates, evidence of strain-induced crystallization and recrystallization was observed. Higher strain rates produced less structural variation because the homogeneous flow of the chains and the crystalline perfection are restricted due to the rapid drawing. In reference to the drawing temperature, EVOH showed a diffusive yielding, and the mechanical parameters were reduced due to the softening of the crystalline region. For EVOH composites, the filler hinders the molecular mobility, causing an increase in the strength and restricting the plastic flow. However, the higher temperature, higher molecular mobility, and ductility are not so affected by the filler content

    The effect of the strain rate and draw temperature on the mechanical behavior of ethylene vinyl alcohol (EVOH) and EVOH composites was analyzed. When EVOH is stretched at moderate strain rates, evidence of strain-induced crystallization and recrystallization was observed. Higher strain rates produced less structural variation because the homogeneous flow of the chains and the crystalline perfection are restricted due to the rapid drawing. In reference to the drawing temperature, EVOH showed a diffusive yielding, and the mechanical parameters were reduced due to the softening of the crystalline region. For EVOH composites, the filler hinders the molecular mobility, causing an increase in the strength and restricting the plastic flow. However, the higher temperature, higher molecular mobility, and ductility are not so affected by the filler content.

  • Sheets of branched poly(lactic acid) obtained by one step reactive extrusion calendering process: Melt rheology analysis

     Cailloux, Jonathan; Santana Pérez, Orlando Onofre; Franco Urquiza, Edgar Adrian; Bou Serra, Jorge; Carrasco, F; Gámez Pérez, José; Maspoch Ruldua, Maria Lluïsa
    Express polymer letters
    Vol. 7, num. 3, p. 304-318
    DOI: 10.3144/expresspolymlett.2013.27
    Date of publication: 2012-03
    Journal article

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    One-step reactive extrusion-calendering process (REX-Calendering) was used in order to obtain sheets of 1mm from two PD,L-LA extrusion grades modified with a styrene-acrylic multifunctional oligomeric agent. In a preliminary internal mixer study, torque versus time was monitored in order to determine chain extender ratios and reaction time. Once all parameters were optimized, reactive extrusion experiments were performed. Independently of the processing method employed, under the same processing conditions, PD,L-LA with the lower D enantiomer molar content revealed a higher reactivity towards the reactive agent, induced by its higher thermal sensitivity. REXCalendering process seemed to minimize the degradations reactions during processing, although a competition between degradation and chain extension/branching reactions took place in both processes. Finally, the rheological characterization revealed a higher degree of modification in the melt rheological behaviour for REX-Calendered samples. © BME-PT.

  • Comparison of plasticized PVC formulations

     Maspoch Ruldua, Maria Lluïsa; Illescas Fernandez, Silvia; Franco Urquiza, Edgar Adrian
    Date: 2012-02-08
    Report

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  • Fracture behavior of quenched poly(lactic acid)

     Gamez Pérez, Jose; Velázquez Infante, Julio César; Franco Urquiza, Edgar Adrian; Pages Figueras, Pedro; Carrasco, F; Santana Pérez, Orlando Onofre; Maspoch Ruldua, Maria Lluïsa
    Express polymer letters
    Vol. 5, num. 1, p. 82-91
    DOI: 10.3144/expresspolymlett.2011.9
    Date of publication: 2011-01
    Journal article

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    The effect of a quenching treatment applied on heated cast sheet extruded films of two poly(lactic acid) (PLA) commercial grades, with different optical purities, was studied. The thermal and mechanical properties of the films, as well as their fracture behavior, were assessed by differential scanning calorimetry (DSC), tensile tests, and the essential work of fracture (EWF) approach. The heating-quenching treatment causes a de-aging effect with an increase in the free volume of polymer chains evidenced by a decrease in the glass transition temperature (Tg) and a decrease in the tensile stiffness and yield stress. As a result, there is an abrupt increase in ductility, finding a dramatic change in the fracture behavior, from brittle to ductile. The use of digital image correlation (DIC) of the strain field analysis during fracture testing has allowed relating the decrease on the yield stress promoted by quenching with the crack propagation kinetics. The use of the EWF method to characterize the fracture toughness of PLA has allowed to measure this enhancement on toughness, finding that the specific essential work of fracture (we) and the plastic term (!wp) parameters increased 120% and 1200%, respectively, after the quenching process.

    The effect of a quenching treatment applied on heated cast sheet extruded films of two poly(lactic acid) (PLA) commercial grades, with different optical purities, was studied. The thermal and mechanical properties of the films, as well as their fracture behavior, were assessed by differential scanning calorimetry (DSC), tensile tests, and the essential work of fracture (EWF) approach. The heating-quenching treatment causes a de-aging effect with an increase in the free volume of polymer chains evidenced by a decrease in the glass transition temperature (Tg) and a decrease in the tensile stiffness and yield stress. As a result, there is an abrupt increase in ductility, finding a dramatic change in the fracture behavior, from brittle to ductile. The use of digital image correlation (DIC) of the strain field analysis during fracture testing has allowed relating the decrease on the yield stress promoted by quenching with the crack propagation kinetics. The use of the EWF method to characterize the fracture toughness of PLA has allowed to measure this enhancement on toughness, finding that the specific essential work of fracture (we) and the plastic term (!wp) parameters increased 120% and 1200%, respectively, after the quenching process.

  • Influence of crystallinity on the fracture toughness of poly(lactic acid)/montmorillonite nanocomposites prepared by twin-screw extrusion

     Gamez Pérez, Jose; Nascimento, L.; Bou Serra, Jorge; Franco Urquiza, Edgar Adrian; Santana Pérez, Orlando Onofre; Carrasco Alonso, Félix Ángel; Maspoch Ruldua, Maria Lluïsa
    Journal of applied polymer science
    Vol. 120, num. 2, p. 896-905
    DOI: 10.1002/app.33191
    Date of publication: 2011-04-15
    Journal article

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  • Caracterización de probetas de PEHD inyectadas

     Arencón Osuna, David; Franco Urquiza, Edgar Adrian; de Redondo Realinho, Vera Cristina
    Date: 2011-11-30
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  • Comparación de formulaciones de PVC plastificado

     Maspoch Ruldua, Maria Lluïsa; Illescas Fernandez, Silvia; Franco Urquiza, Edgar Adrian
    Date: 2011-11-15
    Report

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    Caracteritzar el comportamnet de diferents plastificants en una resina de PVC.

  • Comparación de formulaciones de PVC plastificado: efecto del envejecimiento

     Maspoch Ruldua, Maria Lluïsa; Illescas Fernandez, Silvia; Franco Urquiza, Edgar Adrian
    Date: 2011-11-21
    Report

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  • Caracterización mecánica a tracción y determinación de la densidad y grado de contracción de probetas de PEHD inyectadas

     Arencón Osuna, David; Franco Urquiza, Edgar Adrian; de Redondo Realinho, Vera Cristina
    Date: 2011-11-04
    Report

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  • Predicting the strength of lightweight monocoque sandwich structures

     Steeves, Craig A; Franco Urquiza, Edgar Adrian; Gu, Shixiang
    Date: 2011-02-08
    Report

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  • Modificación del PLA mediante extrusión reactiva para la mejora del procesado, del comportamiento a fractura y de la preparación de nanocompuestos biodegradables

     Santana Pérez, Orlando Onofre; Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian
    Competitive project

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    Determinación de KIC en compuestos de fibra corta a 1 m/s  Open access

     Martinez Benasat, Antonio; Arencón Osuna, David; Franco Urquiza, Edgar Adrian; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina
    Congreso Nacional de Materiales Compuestos
    p. 387-392
    Presentation's date: 2011-07-07
    Presentation of work at congresses

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  • Compuestos de PLA/o-MMT: caracterización morfológica y mecánica

     Velázquez-Infante, Julio; Franco Urquiza, Edgar Adrian; Santana Pérez, Orlando Onofre; Martinez Benasat, Antonio; Maspoch Ruldua, Maria Lluïsa; Gamez Pérez, Jose; Carrasco, F
    Congreso Nacional de Materiales Compuestos
    p. 159-164
    Presentation's date: 2011-07-06
    Presentation of work at congresses

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  • Chain architecture modifications of Poly(Lactic Acid) by reactive extrusion

     Santana Pérez, Orlando Onofre; Callioux, Jonathan; Franco Urquiza, Edgar Adrian; Bou Serra, Jorge; CARRASCO, FELIX; Gámez Pérez, José; Maspoch Ruldua, Maria Lluïsa
    European Polymer Congress
    p. 298-
    Presentation's date: 2011-06-26
    Presentation of work at congresses

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    Fractura postcedencia de polímeros  Open access

     Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian; Santana Pérez, Orlando Onofre; Gamez Pérez, Jose; Sanchez Soto, Miguel Angel; Velasco Perero, Jose Ignacio; Martinez Benasat, Antonio
    Encuentro del Grupo Español de Fractura
    p. 21-29
    Presentation's date: 2011-04-08
    Presentation of work at congresses

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  • Reactive extrusion of poly(lactic acid) with styrene-acrylic-glycidil methacrylate

     Santana Pérez, Orlando Onofre; Cailloux, Jonathan; Franco Urquiza, Edgar Adrian; Bou Serra, Jorge; Carrasco, Félix; Gámez Pérez, José; Maspoch Ruldua, Maria Lluïsa
    EUROTEC
    p. 146-150
    Presentation's date: 2011-11-14
    Presentation of work at congresses

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  • Effect of the recycling and annealing on the mechanical and fracture properties of poly(lactic acid)

     Nascimento, L.; Gamez Pérez, Jose; Santana Pérez, Orlando Onofre; Velasco Perero, Jose Ignacio; Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian
    Journal of polymers and the environment
    Vol. 18, num. 4, p. 654-660
    DOI: 10.1007/s10924-010-0229-5
    Date of publication: 2010-12
    Journal article

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    The aim of this work is to evaluate the use of Poly(lactic acid)(PLA) industrial waste as a source of raw material for certain applications, as well to understand the effects of the annealing on the fracture behaviour of PLA. PLA waste has been simulate by an initial step of extrusion in a single screw extruder and pelletizing. Specimens of virgin and reprocessed PLA were obtained by injection molding. An anneling treatment capable of increasing the percentage of cristallinity (determined by differential scanning calorimetry) was also analyzed in reprocessed and non reprocessed specimens. The fracture behaviour was studied at slow and high testing speed, applying the linear elastic fracture mechanics (LEFM) on single edge notched bend (SENB) specimens. This study revealed that the fracture toughness of the reprocessed PLA was basically the same that the virgin PLA and also that the increase in the crystalline fraction produced an improvement on the fracture toughness, at slow loagind rate.

  • The effect of organo-modifier on the structure and properties of poly[ethylene¿(vinyl alcohol)]/organo-modified montmorillonite composites

     Franco Urquiza, Edgar Adrian; Gamez Pérez, Jose; Sanchez Soto, Miguel Angel; Santana Pérez, Orlando Onofre; Maspoch Ruldua, Maria Lluïsa
    Polymer international
    Vol. 59, num. 6, p. 778-786
    DOI: 10.1002/pi.2788
    Date of publication: 2010-02-02
    Journal article

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  • Aplicación de la mecánica de la fractura post-cedencia a polímeros

     Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian; Gamez Pérez, Jose; Sanchez Soto, Miguel Angel; Velasco Perero, Jose Ignacio; Santana Pérez, Orlando Onofre; Martinez Benasat, Antonio
    Revista latinoamericana de metalurgia y materiales
    Vol. 30, num. 2, p. 101-118
    Date of publication: 2010-07-30
    Journal article

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    La técnica del trabajo esencial de fractura (EWF) se ha utilizado en la caracterización a fractura de materiales que desarrollan una amplia ductilidad y donde ocurre una completa cedencia antes del inicio de la propagación de la grieta. De esta manera, la técnica EWF caracteriza la fractura post-cedencia determinando dos parámetros: el trabajo esencial específico de fractura (we), relacionado con la superficie donde ocurre el proceso real de fractura, y el trabajo no esencial específico de fractura (wp), relacionado con el trabajo plástico realizado en la zona exterior de la zona de fractura. La técnica EWF ha sido utilizada satisfactoriamente, especialmente en polímeros, permitiendo el estudio de la influencia de distintas variables sobre el comportamiento a fractura. Su elevada sensibilidad así como su fácil aplicabilidad le confieren amplias ventajas sobre otras técnicas tales como la integral J. En este trabajo se describen los fundamentos de la técnica EWF y se recopilan algunos ejemplos de su aplicación, presentando un breve resumen de las aportaciones más relevantes realizadas por nuestro grupo de investigación sobre la técnica del EWF.

  • Influence of processing on the ethylene-vinyl alcohol (EVOH) properties: Application of the successive self-nucleation and annealing (SSA) technique

     Franco Urquiza, Edgar Adrian; Santana Pérez, Orlando Onofre; Gamez Pérez, Jose; Martinez Benasat, Antonio; Maspoch Ruldua, Maria Lluïsa
    Express polymer letters
    Vol. 4, num. 3, p. 153-160
    DOI: 10.3144/expresspolymlett.2010.20
    Date of publication: 2010-03
    Journal article

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    Films of EVOH copolymers, processed three times by twin-screw extrusion were prepared using a cast-film line. The variation on the melt flow rate (MFR) and rheological behaviour of the films were determined, as well as the thermal properties assessed by differential scanning calorimetry (DSC) and dynamic-mechanical thermal analysis (DMTA). As the results showed that the reprocessing induced an increase in the viscosity and orientation of the films, it was suggested that structural modifications from chain-extension or cross-linking reactions promoted by hydroxyl and residual acetoxyl groups, could be occurring. The successive self-nucleation and annealing (SSA) technique was applied, evidencing the structural modifications on the EVOH copolymer.

  • Comportamiento a fractura de dos grados comerciales PLA: influencia de la estructura cristalina

     Gamez Pérez, Jose; Velazquez, Julio; Franco Urquiza, Edgar Adrian; Velasco Perero, Jose Ignacio; Maspoch Ruldua, Maria Lluïsa
    Encuentro del Grupo Español de Fractura
    p. 647-652
    Presentation's date: 2010-03-17
    Presentation of work at congresses

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    En este trabajo se ha estudiado el efecto de un tratamiento de rejuvenecimiento aplicado a láminas obtenidas por extrusión-calandra a partir de dos grados comerciales de PLA, con diferentes purezas ópticas. Se han evaluado las propiedades térmicas mediante calorimetría diferencial de barrido (DSC), las propiedades mecánicas, mediante ensayos a tracción y el comportamiento a fractura con la técnica del trabajo esencial de fractura (EWF). El tratamiento de rejuvenecimiento provoca un aumento del volumen libre de las cadenas, que se manifiesta en un descenso de la temperatura de transición vítrea (Tg) y una disminución de la rigidez y tensión a cedencia con un aumento significativo de la ductilidad. Este incremento en la ductilidad permitió la aplicación de la técnica del EWF, pudiendo relacionar los parámetros obtenidos con la caracterización térmica y mecánica.

  • Microestructura y comportamiento mecánico y a fractura de nanocompuestos anisotrópicos de PMMA con montmorillonita

     de Redondo Realinho, Vera Cristina; de Sousa Pais Antunes, Marcelo; Arencón Osuna, David; Franco Urquiza, Edgar Adrian; Velasco Perero, Jose Ignacio
    Congreso Nacional de Jóvenes Investigadores en Polímeros
    Presentation's date: 2010-05-05
    Presentation of work at congresses

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  • Estudio de la estabilidad térmica en nanocompuestos POM/POSS

     Illescas Fernandez, Silvia; Sanchez Soto, Miguel Angel; Arencón Osuna, David; Gamez Pérez, Jose; Arostegui, Asier; Franco Urquiza, Edgar Adrian
    Congreso Nacional de Materiales
    p. 127
    Presentation's date: 2010-06-23
    Presentation of work at congresses

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    Debido a sus excelentes propiedades termo-mecánicas el polióxido de metileno (POM) es un polímero de gran interés industrial. Sin embargo, uno de sus mayores inconvenientes es su tendencia a la termooxidación que ocasiona que algunas piezas fallen en servicio como resultado de una degradación ocurrida durante el procesado [1, 2]. Para mejorar su estabilidad térmica se han obtenido nanocompuestos mezclando la matriz de POM con diferentes tipos de silsesquioxanos poliédricos (POSS) en proporciones por debajo del 5% en peso [3]. Se han llevado a cabo diferentes tratamientos de envejecimiento térmico de los nanocompuestos variando las condiciones de proceso (tiempo y temperatura). Posteriormente se ha realizado una caracterización por medio de ensayos térmicos y espectroscópicos. Los resultados han demostrado que dependiendo de la naturaleza del POSS usado puede alcanzarse una gran mejora de la resistencia a la degradación respecto de la matriz pura incluso con bajos contenidos de POSS.

  • Efecto de la agudización de la entalla por femtoláser en el trabajo esencial de fractura

     Martinez Benasat, Antonio; Segovia, Angelica; Rodríguez Pérez, Jesús; Franco Urquiza, Edgar Adrian
    Anales de mecánica de la fractura
    Vol. 26, p. 537-543
    Date of publication: 2009-03-25
    Journal article

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  • Preparación y caracterización de nanocompuestos Evoh/Montmorillonita

     Franco Urquiza, Edgar Adrian
    Department of Materials Science and Metallurgy, Universitat Politècnica de Catalunya
    Theses

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  • Fracture behaviour of poly[ethylene¿(vinyl alcohol)]/organo-clay composites

     Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian; Gamez Pérez, Jose; Santana Pérez, Orlando Onofre; Sanchez Soto, Miguel Angel
    Polymer international
    Vol. 58, num. 6, p. 648-655
    DOI: 10.1002/pi.2574
    Date of publication: 2009-04-14
    Journal article

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    BACKGROUND: Ethylene–(vinyl alcohol) (EVOH) copolymer/organo-modified montmorillonite (OMMT) composites were investigated. Composites with two different percentages by weight of OMMT were prepared using a melt-extrusion procedure in a twin-screw extruder, using EVOH asmatrix. Filmsmade of EVOH and EVOH/OMMT composites were prepared in a cast-film extrusion line. RESULTS: The mechanical properties were evaluated by tensile tests and the fracture behaviour was analysed using the essential-work-of-fracture (EWF) method. Fracture characterization was carried out for the two main processing directions: melt flow direction and transverse direction. Fractographic observations were made using scanning electron microscopy. CONCLUSION: The tensile test results indicated good compatibility between EVOH and OMMT. In addition, the fracture tests showed the influence of the clay particle arrangement on the fracture behaviour, showing an increase in the specific essential work of fracture, we, which was attributed to the EVOH–OMMT interaction. The plastic term, βwp, showed different trends depending on the test direction, explained by the size of the plastic zone and the restrictions to the EVOH plastic flow promoted by the clay particles. In this sense, the EWF method is shown to be a very useful tool for the analysis of structure–property relationships in polymer–organo-clay composites.

  • Aplicación de la técnica de autonucleación-recocido sucesivos (SSA) en un copolímero EVOH: Efecto del procesamiento

     Santana Pérez, Orlando Onofre; Jabareen, A Al; Franco Urquiza, Edgar Adrian; Maspoch Ruldua, Maria Lluïsa
    Congreso Nacional de Materiales
    p. 865-868
    Presentation of work at congresses

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  • Fracture behaviour of poly(lactic acid) (PLA) and PLA/MMT nanocompoistes

     Nascimento, L.; Gamez Pérez, Jose; Franco Urquiza, Edgar Adrian; Maspoch Ruldua, Maria Lluïsa
    International Conference on Fracture of Polymers, Composites and Adhesives
    Presentation's date: 2008-09-07
    Presentation of work at congresses

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  • Aplicación de la técnica de autonucleación-recocido sucesivos (SSA) en un copolímero evoh: efecto del procesamiento

     Santana Pérez, Orlando Onofre; Al-Jabareen, Ahmad; Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian
    Congreso Nacional de Materiales
    p. 865-868
    Presentation's date: 2008-06-18
    Presentation of work at congresses

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  • Preparación y caracterización de nanocompuestos de EVOH 44

     Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian; Gamez Pérez, Jose; Erikson, M; Porta, G; Sanchez Soto, Miguel Angel; Santana Pérez, Orlando Onofre
    Encuentro del Grupo Español de Fractura
    p. 347-352
    Presentation of work at congresses

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  • Preparación y caracterización de nanocompuestos de EVOH 44

     Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian; Gamez Pérez, Jose; Erikson, M; Porta, G; Sanchez Soto, Miguel Angel; Santana Pérez, Orlando Onofre
    Anales de mecánica de la fractura
    Vol. 24, num. 1, p. 347-352
    Date of publication: 2007-03
    Journal article

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  • Preparación y caracterización de nanocompuestos de Evoh 44

     Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian; Gamez Pérez, Jose; Eriksson, Maria; Porta, Galdric; Sanchez Soto, Miguel Angel; Santana Pérez, Orlando Onofre
    Encuentro del Grupo Español de Fractura
    p. 347-352
    Presentation's date: 2007-03-27
    Presentation of work at congresses

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    Se han preparado y caracterizado films de EVOH y de diferentes mezclas con una arcilla de tipo Montmorillonita. Las mezclas se obtuvieron por el método de mezclado en fundido, utilizando una extrusora doble husillo. Mediante procesos de coextrusión plana se elaboraron films con dos espesores diferentes para todos los materiales. El estudio térmico se llevó a cabo empleando las técnicas de calorimetría diferencial de barrido (DSC) y análisis térmico dinamomecánico (DMTA). Para el comportamiento mecánico, se realizaron ensayos a tracción, mientras que para el de fractura se utilizó la técnica del trabajo esencial de fractura (EWF). El análisis fractográfico se realizó por medio de microscopía electrónica de barrido (MEB). Las propiedades se relacionaron con el número de procesados, el porcentaje de Montmorillonita contenida en la matriz y el espesor del film.

  • Comportamiento a fractura de films de nanocompuestos de un copolímero EVOH

     Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian; Boggio, M; Boitel, H; Velasco Perero, Jose Ignacio; Santana Pérez, Orlando Onofre
    Anales de mecánica de la fractura
    Vol. 23, p. 533-538
    Date of publication: 2006-03
    Journal article

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  • Comportamiento a fractura de filmes de nanocompuestos de un copolímero EVOH

     Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian; Boggio, M; Boitel, H; Velasco Perero, Jose Ignacio; Santana Pérez, Orlando Onofre
    Encuentro del Grupo Español de Fractura
    p. 533-538
    Presentation's date: 2006-03-18
    Presentation of work at congresses

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  • Comportamiento a fractura de films de nanocompuestos de un copolímero Evoh

     Maspoch Ruldua, Maria Lluïsa; Franco Urquiza, Edgar Adrian; Boggio, M; Boitel, H; Velasco Perero, Jose Ignacio; Santana Pérez, Orlando Onofre
    Encuentro del Grupo Español de Fractura
    p. 533-538
    Presentation's date: 2006-03-29
    Presentation of work at congresses

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    Se analizó el comportamiento a fractura de films de nanocompuestos de un copolímero EVOH con diferentes porcentajes en peso de dos tipos de arcillas montmorillonitas. Los nanocompuestos fueron obtenidos a través de un proceso de extrusión de doble husillo. Mediante una extrusora calandra, se obtuvieron los diferentes films con un espesor de aproximadamente 300μm. El estudio morfológico se llevó a cabo mediante difracción de rayos X y microscopia electrónica de transmisión (MET) observando rasgos de intercalación con algunos porcentajes. El análisis fractográfico se realizó por microscopia electrónica de barrido (MEB). El comportamiento mecánico se analizó mediante ensayos de tracción y el de fractura mediante la técnica de trabajo esencial de fractura (EWF). Se encontraron variaciones importantes en la tenacidad de los compuestos en función del tipo y porcentaje de arcilla que se relacionan con las morfologías resultantes.