{"id":116562,"date":"2018-03-11T10:45:46","date_gmt":"2018-03-11T10:45:46","guid":{"rendered":"https:\/\/www.deberes.net\/tesis\/sin-categoria\/materiales-barrera-nanoestructuras-basadas-en-polietileno-y-nanoarcillas\/"},"modified":"2018-03-11T10:45:46","modified_gmt":"2018-03-11T10:45:46","slug":"materiales-barrera-nanoestructuras-basadas-en-polietileno-y-nanoarcillas","status":"publish","type":"post","link":"https:\/\/www.deberes.net\/tesis\/murcia\/materiales-barrera-nanoestructuras-basadas-en-polietileno-y-nanoarcillas\/","title":{"rendered":"Materiales barrera. nanoestructuras basadas en polietileno y nanoarcillas"},"content":{"rendered":"

Tesis doctoral de Carmen Fernandez Ayuso <\/strong><\/h2>\n

Resumen el objetivo de esta tesis es el desarrollo de nanoestructuras a partir de nanoarcillas y polietileno para mejorar sus propiedades barrera al ox\u00edgeno de este pol\u00edmero, que adem\u00e1s conserve las propiedades t\u00e9rmicas y \u00f3pticas. el trabajo se ha dividido en varias fases con el objetivo de evaluar y comparar diferentes m\u00e9todos de incorporaci\u00f3n de las nanoarcillas a la matriz polim\u00e9rica: en la primera fase se ha utilizado la tecnolog\u00eda "capa a capa" para crear films de polietileno con nanoarcillas. Estos films se han construido intercalando capas sucesivas de poliacrilamida y montmorillonita (cloisita na+, no modificada org\u00e1nicamente) sobre un film de polietileno sometido a tratamiento corona, logrando una disminuci\u00f3n de la permeabilidad al ox\u00edgeno, lo cual se debe a la nanoestructura formada en el film, que provoca un camino tortuoso para la difusi\u00f3n de las mol\u00e9culas de ox\u00edgeno. Las propiedades \u00f3pticas han sido analizadas encontrando que los valores de transparencia son superiores al 90% en todas las muestras. esta tecnolog\u00eda ha sido llevada a cabo mediante dos metodolog\u00edas: -inicialmente se construyeron las nanoestructuras aplicando las bicapas mediante spray. Los resultados mostraron que tras 20 bicapas los valores de permeabilidad al ox\u00edgeno disminuyen en un 67% respecto al ldpe puro, pero al incrementar el n\u00famero de bicapas a 30 los resultados obtenidos s\u00f3lo mejoran los valores de permeabilidad en un 40,22% respecto al ldpe puro. La tecnolog\u00eda utilizada para formar las bicapas mediante dispersi\u00f3n con spray de las disoluciones en la matriz polim\u00e9rica, da lugar a capas muy finas, de aproximadamente 0,2 micras\/bicapa. Al acumular un exceso de bicapas, y ser \u00e9stas tan finas, la estructura se desmorona. – posteriormente, se construyeron las nanoaestructuras mediante tecnolog\u00eda "capa a capa" por inmersi\u00f3n de la matriz polim\u00e9rica en las disoluciones. Con tan s\u00f3lo 9 bicapas se lograron excelentes valores de permeabilidad, con una reducci\u00f3n del 99.92% respecto al polietileno puro, pasando de un film barrera al ox\u00edgeno pobre, a un film con una alta capacidad barrera al ox\u00edgeno (3,66 cm3\/m2\u00c2\u00b7 d\u00eda), con tan s\u00f3lo 48 micras de espesor total. Ello demuestra que las bicapas formadas por inmersi\u00f3n, aunque de mayor espesor (apr\u00f3ximadamente 0,4 micras\/bicapa), son m\u00e1s homog\u00e9neas y estables, formando una nanoestructura m\u00e1s eficiente, lo que permite, con un film substrato m\u00e1s delgado, obtener mejores resultados de permeabilidad al ox\u00edgeno. en la segunda fase de la tesis las nanoarcillas (modificadas org\u00e1nicamente) han sido incorporadas en el seno de la matriz de polietileno en forma de masterbatch mediante mezclado con extrusora de doble husillo y posterior obtenci\u00f3n de films con extrusora de soplado. – en primer lugar, se probaron dos tipos de nanoarcillas comerciales modificadas org\u00e1nicamente (cloisita 15a y cloisita 20a) no obteniendo con ninguna de las dos, mejora apreciable sobre las propiedades del polietileno, lo cual se ha atribuido a la formaci\u00f3n de estructuras agregadas y a la baja adhesi\u00f3n entre el polietileno y la nanoarcilla. – ante los resultados obtenidos, se incorpor\u00f3 a los masterbatches un compatibilizante polietileno-nanoarcilla. Como consecuencia, los mejores resultados mostraron una reducci\u00f3n en la permeabilidad al ox\u00edgeno de 22,90% con una concentraci\u00f3n de nanoarcilla cloisita 15a del 4%. Al incorporar el compatibilizante se consigue una mejor homogeneizaci\u00f3n y dispersi\u00f3n de las nanoarcillas, dando lugar a mejores resultados. los mejores resultados de la tesis han sido obtenidos con la tecnolog\u00eda "capa a capa" mediante inmersi\u00f3n por la precisi\u00f3n en la orientaci\u00f3n de las nanopart\u00edculas y sobre la morfolog\u00eda de la matriz polim\u00e9rica, lo cual no se puede alcanzar con las tecnolog\u00edas convencionales. abstract the objective of this thesis is the development of nanostructures from nanoclays and polyethylene to improve oxygen barrier properties of this polymer, maintaining its thermal and optical properties. this research work has been split into several phases in order to evaluate and compare different methods of nanoclays incorporation into polymer: in the first phase, "layer by layer" technology has been used to create polyethylene nanoclays films. These films have been constructed inserting successive layers of polyacrylamide and montmorillonita (cloisite na+, non-organic modification) grown on a ldpe film substrate submitted to corona treatment. Using this technology oxygen permeability is decreased, as consequence of a brick wall nanostructure present within the film that produces a tortuous path for diffusing oxygen molecules. Optical properties have been analyzed and transparency greater than 90% has been showed in all samples. this technology has been carried out through two methodologies: – firstly, nanostructures were built by spray. Results showed that after 20 bilayers the oxygen permeability is decreased around 67% below the pure ldpe, but increasing to 30 bilayers results only decreased a 40,22% below the pure ldpe. Spray technology used to build these bilayers generate very thin ones, only about of 0,2 micron. When an excess of bilayers are accumulated, and also due to their thickness, the nanobrick structure is collapsed. – after that, nanostructures were built by immersion of polymer film into solutions. Excellent oxygen permeability results were reached with only 9 bilayers, with a reduction of 99,92% below pure polyethylene, changing from a poor oxygen barrier film to a high oxygen barrier one (3,66 cm3\/m2\u00c2\u00b7 day), with a total thickness of 48 microns. This fact show that bilayers built by immersion, although having a high thickness (around 0,4 microns\/bilayer), are more homogeneous and uniform, making a more efficient structure, which allow, with a thinner substrate film, to reach better oxygen permeability results. in the second phase of this doctoral thesis, nanoclays (organically modified) have been incorporated to the polyethylene matrix as masterbatch mixing the components in a twin screw extruder, and after obtaining the films using a blown film extruder. – firstly, two types of commercial organically modified nanoclays (cloisite 15a y cloisite 20a) were tested, and no substantial improvements were obtained in the polyethylene properties. This fact is attributed to the aggregate structures formed and a low adhesion between polyethylene and nanoclay, allowing the oxygen diffusion through the film. – after these obtained results, a polyethylene-nanoclay compatibilizer was aggregated to masterbatches. Consequently, the best results showed an oxygen permeability reduction of 22,90% with 4% concentration of nanoclay cloisite 15a. Therefore, compatibilizer incorporation gives a better homogenization and dispersion of nanoclays, giving rise to better results. finally, it is emphasized that the best results have been reached using "layer by layer" technology by immersion, which is attributed to the high control over nanostructures formation, obtained by an excellent accurate on nanoparticles orientation and polymer matrix morphology, these cannot be reached by conventional extrusion technologies, which only offer a partial control over filling morphology scattered in polymer matrix.<\/p>\n

 <\/p>\n

Datos acad\u00e9micos de la tesis doctoral \u00abMateriales barrera. nanoestructuras basadas en polietileno y nanoarcillas<\/strong>\u00ab<\/h3>\n
    \n
  • T\u00edtulo de la tesis:<\/strong>\u00a0 Materiales barrera. nanoestructuras basadas en polietileno y nanoarcillas <\/li>\n
  • Autor:<\/strong>\u00a0 Carmen Fernandez Ayuso <\/li>\n
  • Universidad:<\/strong>\u00a0 Murcia<\/li>\n
  • Fecha de lectura de la tesis:<\/strong>\u00a0 31\/10\/2014<\/li>\n<\/ul>\n

     <\/p>\n

    Direcci\u00f3n y tribunal<\/h3>\n
      \n
    • Director de la tesis<\/strong>\n
        \n
      • Elisa Gomez Gomez<\/li>\n<\/ul>\n<\/li>\n
      • Tribunal<\/strong>\n
          \n
        • Presidente del tribunal: Antonio Francisco Marcilla gomis <\/li>\n
        • Mar\u00eda isabel Beltran rico (vocal)<\/li>\n
        • Manuel Hern\u00e1ndez c\u00f3rdoba (vocal)<\/li>\n
        • gerardo Hidalgo llinas (vocal)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n

           <\/p>\n","protected":false},"excerpt":{"rendered":"

          Tesis doctoral de Carmen Fernandez Ayuso Resumen el objetivo de esta tesis es el desarrollo de nanoestructuras a partir de […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[9176,8235],"tags":[230060,230059,50357,203840,12757,230061],"class_list":["post-116562","post","type-post","status-publish","format-standard","hentry","category-materiales-plasticos","category-murcia","tag-antonio-francisco-marcilla-gomis","tag-carmen-fernandez-ayuso","tag-elisa-gomez-gomez","tag-gerardo-hidalgo-llinas","tag-manuel-hernandez-cordoba","tag-maria-isabel-beltran-rico"],"_links":{"self":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/116562","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/comments?post=116562"}],"version-history":[{"count":0,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/116562\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/media?parent=116562"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/categories?post=116562"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/tags?post=116562"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}