{"id":109836,"date":"2011-04-07T00:00:00","date_gmt":"2011-04-07T00:00:00","guid":{"rendered":"https:\/\/www.deberes.net\/tesis\/sin-categoria\/nanobiocomposites-basados-en-poliuretanos-elastomericos-con-nanoarcillas-y-nanocristales-de-celulosa\/"},"modified":"2011-04-07T00:00:00","modified_gmt":"2011-04-07T00:00:00","slug":"nanobiocomposites-basados-en-poliuretanos-elastomericos-con-nanoarcillas-y-nanocristales-de-celulosa","status":"publish","type":"post","link":"https:\/\/www.deberes.net\/tesis\/pais-vasco-euskal-herriko-unibertsitatea\/nanobiocomposites-basados-en-poliuretanos-elastomericos-con-nanoarcillas-y-nanocristales-de-celulosa\/","title":{"rendered":"Nanobiocomposites basados en poliuretanos elastom\u00e9ricos con nanoarcillas y nanocristales de celulosa"},"content":{"rendered":"<h2>Tesis doctoral de <strong> Lorena Rueda Larraz <\/strong><\/h2>\n<p>Polyurethanes constitute a great polymers family which, due to the versatility in composition and design, can include a wide range of application fields. Specifically, thermoplastic polyurethane elastomers are considered to be one of the most important materials in biomedical devices because of their physico-chemical, thermal and mechanical properties with excellent biocompatibility relationship. in this investigation, segmented thermoplastic polyurethanes have been prepared and the physico-chemical, thermal, morphological and mechanical characterization have been performed in order to understand the microstructure\/property relationships, which result important to know the behaviour and the influence on final properties of the materials. the evaluation of the physical interactions through hydrogen bonding between hard\/hard segments and hard\/soft segments in polyurethane have allowed to conclude that different microstructures can be obtained varying reactants molar ratio. on the other hand, in last years, the nanotechnology and also the use of renewable sources have provoked an increasing interest in the composites development and design. In general, reinforcements at nanometric level can induce better properties than traditional ones due to the high surface area and aspect ratio. However, the incorporation of hydrophilic filler into a hydrophobic matrix as polyurethane involves compatibilization methods between them and the development of adequate procedure to improve interfacial adhesion. in this work, different polyurethane nanocomposites have been synthesized and characterized based on two nanoreinforcements: polyurethane\/nanoclays and polyurethane\/cellulose nanocrystals. in the first stage, polyurethane nanocomposites based on chemically modified inorganic nanoreinforcement at different contents, cloisite 30b (c30b), have been synthesized in thf solution by means of in situ polymerization. Besides, the anchorage of the nanoclay and also the role of the nanoreinforcement on the microstructure-property relationships in the resulting materials have been analyzed. in the second stage, cellulose nanocrystals (cnc) have been isolated from microcrystalline cellulose by means of acid hydrolysis with sulfuric acid. In addition, cnc functionalization has been performed through the chemical reaction between hydroxyl groups from cnc and isocyanate groups from hdi varying the molar ratio. Chemical modification has been evaluated by several characterization techniques and the substitution degree of the anchored chains in cnc has been determined. nanocomposites based on elastomeric polyurethane with different cnc loadings have been prepared by two methods: solvent casting and in situ polymerization. Moreover, thermal, mechanical and morphological characterization has been analyzed taking into account the cnc effect on the microstructure. the cnc functionalization influence and the variation of cnc aspect ratio on the nanocomposites have been analyzed, resulting critic parameters to obtain an improvement in materials properties, as well as the processing method. finally, from the viewpoint of polyurethane applications focused on biomedical devices, the biostability and biocompatibility evaluation can be considered necessary to determine the useful life time in this type of materials without loss in final properties. For this reason, hydrolytic degradation tests and in vitro biocompatibility essays have been performed to evaluate the influence of nanoreinforcement on polymeric matrix and also the changes in biological behaviour, to confirm that these materials are available as possible candidates for biomedical applications.  los poliuretanos constituyen una gran familia de pol\u00edmeros que, debido a la versatilidad en cuanto a su composici\u00f3n y dise\u00f1o, abarcan un amplio rango de aplicaciones. En concreto, los poliuretanos termopl\u00e1sticos elast\u00f3meros han sido uno de los materiales polim\u00e9ricos con mayor proyecci\u00f3n en la fabricaci\u00f3n de biomateriales debido a la id\u00f3nea relaci\u00f3n que presentan en cuanto a sus propiedades f\u00edsico-qu\u00edmicas, t\u00e9rmicas y mec\u00e1nicas con su excelente biocompatibilidad.  en este trabajo se han sintetizado matrices polim\u00e9ricas tipo poliuretano termopl\u00e1stico segmentado y caracterizado f\u00edsico-qu\u00edmica, t\u00e9rmica, morfol\u00f3gica y mec\u00e1nicamente, para profundizar en el conocimiento de la relaci\u00f3n microestructura\/propiedades, que resulta clave para comprender su comportamiento e influencia en las propiedades finales de estos materiales. El estudio de las interacciones mediante puentes de hidr\u00f3geno presentes en y entre los segmentos r\u00edgidos y flexibles del poliuretano ha permitido concluir que en funci\u00f3n de la relaci\u00f3n molar de los componentes se obtienen diferentes microestructuras. por otra parte, en los \u00faltimos a\u00f1os, la nanotecnolog\u00eda y el uso de recursos renovables han suscitado gran inter\u00e9s en el desarrollo y dise\u00f1o de composites. En general, los refuerzos a escala nanom\u00e9trica ofrecen grandes ventajas sobre los tradicionales debido a su mayor \u00e1rea superficial y relaci\u00f3n de aspecto. Sin embargo, la incorporaci\u00f3n de un refuerzo hidrof\u00edlico a una matriz hidrof\u00f3bica de tipo poliuretano, conlleva el empleo de procedimientos de compatibilizaci\u00f3n entre ambos y el desarrollo de m\u00e9todos adecuados de procesado que garanticen una adecuada uni\u00f3n interfacial entre ellos.  en este trabajo se han preparado y caracterizado dos familias de nanocomposites: nanoarcillas\/poliuretano y nanocristales de celulosa\/poliuretano. en una primera fase, se han sintetizado y caracterizado nanocomposites con diferentes contenidos de refuerzo inorg\u00e1nico de origen mineral, qu\u00edmicamente modificado, cloisite 30b (c30b), en soluci\u00f3n mediante polimerizaci\u00f3n in situ de la matriz poliuretano. Se ha analizado por una parte, el anclaje qu\u00edmico de la nanoarcilla a la matriz y por otra, el papel que ejerce el nanorefuerzo y los efectos posibles de su dispersi\u00f3n en la relaci\u00f3n microestructura-propiedades de los materiales obtenidos. en una segunda fase, se han extra\u00eddo nanocristales de celulosa a partir de celulosa microcristalina mediante hidr\u00f3lisis con \u00e1cido sulf\u00farico. Se han obtenido cnc de diferente relaci\u00f3n de aspecto variando las condiciones de hidr\u00f3lisis. Se ha llevado a cabo la funcionalizaci\u00f3n de cnc, con diversas relaciones molares, a trav\u00e9s de la reacci\u00f3n qu\u00edmica entre los grupos hidroxilo del nanorefuerzo y los grupos isocianato del mon\u00f3mero utilizado en la s\u00edntesis de los poliuretanos. La modificaci\u00f3n qu\u00edmica ha sido evaluada mediante diversas t\u00e9cnicas de caracterizaci\u00f3n y se ha determinado el grado de sustituci\u00f3n de las cadenas ancladas a los cnc. se han preparado y caracterizado nanocomposites basados en matrices poliuretano elastom\u00e9rico incorporando diferentes cantidades de cnc mediante soluci\u00f3n y polimerizaci\u00f3n in situ, evaluando las propiedades t\u00e9rmicas, mec\u00e1nicas y morfol\u00f3gicas de estos materiales y la influencia que ejerce el nanorefuerzo en la microestructura. Se ha estudiado la influencia de la modificaci\u00f3n qu\u00edmica de los nanocristales y la variaci\u00f3n de la relaci\u00f3n de aspecto de los cnc en las propiedades de los nanocomposites, resultando par\u00e1metros cr\u00edticos, as\u00ed como el efecto del m\u00e9todo de preparaci\u00f3n.    finalmente, desde la perspectiva del uso y disfrute de estos poliuretanos enfocados hacia aplicaciones biom\u00e9dicas, resulta necesario evaluar su estabilidad respecto a la biodegradaci\u00f3n y biocompatibilidad, de cara a determinar el tiempo de vida real sin que conlleve la p\u00e9rdida de propiedades finales. Por ello, se ha evaluado la bioestabilidad, mediante ensayos de degradaci\u00f3n hidrol\u00edtica, as\u00ed como la biocompatibilidad, mediante ensayos in vitro, del poliuretano elastom\u00e9rico y la influencia que ejercen la introducci\u00f3n de los refuerzos en la matriz polim\u00e9rica analizando los posibles cambios en el comportamiento biol\u00f3gico.<\/p>\n<p>&nbsp;<\/p>\n<h3>Datos acad\u00e9micos de la tesis doctoral \u00ab<strong>Nanobiocomposites basados en poliuretanos elastom\u00e9ricos con nanoarcillas y nanocristales de celulosa<\/strong>\u00ab<\/h3>\n<ul>\n<li><strong>T\u00edtulo de la tesis:<\/strong>\u00a0 Nanobiocomposites basados en poliuretanos elastom\u00e9ricos con nanoarcillas y nanocristales de celulosa <\/li>\n<li><strong>Autor:<\/strong>\u00a0 Lorena Rueda Larraz <\/li>\n<li><strong>Universidad:<\/strong>\u00a0 Pa\u00eds vasco\/euskal herriko unibertsitatea<\/li>\n<li><strong>Fecha de lectura de la tesis:<\/strong>\u00a0 04\/07\/2011<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3>Direcci\u00f3n y tribunal<\/h3>\n<ul>\n<li><strong>Director de la tesis<\/strong>\n<ul>\n<li>M. Aranzazu Eceiza Mendiguren<\/li>\n<\/ul>\n<\/li>\n<li><strong>Tribunal<\/strong>\n<ul>\n<li>Presidente del tribunal: i\u00f1aki Mondragon ega\u00f1a <\/li>\n<li>alfonso Jim\u00e9nez migall\u00f3n (vocal)<\/li>\n<li>lars Berglund (vocal)<\/li>\n<li>Jos\u00e9 Mar\u00eda Kenny (vocal)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tesis doctoral de Lorena Rueda Larraz Polyurethanes constitute a great polymers family which, due to the versatility in composition and [&hellip;]<\/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":[30403,19398,12909,13316,19337],"tags":[78739,13312,139406,128541,219527,79011],"class_list":["post-109836","post","type-post","status-publish","format-standard","hentry","category-analisis-de-macromoleculas","category-elastomeros","category-pais-vasco-euskal-herriko-unibertsitatea","category-polimeros-compuestos","category-poliuretanos","tag-alfonso-jimenez-migallon","tag-inaki-mondragon-egana","tag-jose-maria-kenny","tag-lars-berglund","tag-lorena-rueda-larraz","tag-m-aranzazu-eceiza-mendiguren"],"_links":{"self":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/109836","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=109836"}],"version-history":[{"count":0,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/109836\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/media?parent=109836"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/categories?post=109836"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/tags?post=109836"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}