Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance composites
Bitumen, by-product resulting from the vacuum distillation of crude oíl, consists of a complex mixture of organic and inorganic compounds, comprising mainly aliphatic, aromatic and naphthenic hydrocarbons. Even though its composition greatly depends on the crude oíl source and the refining process,...
| Autor: | |
|---|---|
| Formato: | tesis doctoral |
| Fecha de publicación: | 2017 |
| País: | España |
| Recursos: | Universidad de Huelva (UHU) |
| Repositorio: | Arias Montano. Repositorio Institucional de la Universidad de Huelva |
| Idioma: | inglés |
| OAI Identifier: | oai:ariasmontano.uhu.es:10272/16092 |
| Acesso em linha: | http://hdl.handle.net/10272/16092 |
| Access Level: | acceso abierto |
| Palavra-chave: | Materiales bituminosos Polímeros Reología Nanoclay Isocyanate Bitumen Rheology Composite Nanoarcilla Isocianato Betún |
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| dc.title.none.fl_str_mv |
Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance composites |
| title |
Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance composites |
| spellingShingle |
Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance composites Ortega Bravo, Francisco José Materiales bituminosos Polímeros Reología Nanoclay Isocyanate Bitumen Rheology Composite Nanoarcilla Isocianato Betún Reología |
| title_short |
Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance composites |
| title_full |
Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance composites |
| title_fullStr |
Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance composites |
| title_full_unstemmed |
Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance composites |
| title_sort |
Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance composites |
| dc.creator.none.fl_str_mv |
Ortega Bravo, Francisco José |
| author |
Ortega Bravo, Francisco José |
| author_facet |
Ortega Bravo, Francisco José |
| author_role |
author |
| dc.contributor.none.fl_str_mv |
Navarro Domínguez, Francisco Javier García Morales, Moisés Universidad de Huelva. Departamento de Ingeniería Química, Química Física y Ciencias de los Materiales |
| dc.subject.none.fl_str_mv |
Materiales bituminosos Polímeros Reología Nanoclay Isocyanate Bitumen Rheology Composite Nanoarcilla Isocianato Betún Reología |
| topic |
Materiales bituminosos Polímeros Reología Nanoclay Isocyanate Bitumen Rheology Composite Nanoarcilla Isocianato Betún Reología |
| description |
Bitumen, by-product resulting from the vacuum distillation of crude oíl, consists of a complex mixture of organic and inorganic compounds, comprising mainly aliphatic, aromatic and naphthenic hydrocarbons. Even though its composition greatly depends on the crude oíl source and the refining process, a basic characterisation can be performed based on its solubility in n-alkanes, resulting in maitenes, further subdivided into saturates, aromatics and resins; and asphaltenes, which constitute the most polar fraction of bltumen. This separation configures the so-called SARAs fractions of bitumen. Amongst bitumen properties, waterproofing, ductility, adhesiveness, and resistance to weathering and chemicals have favoured its development for a wide range of applications, mainly in the fields of pavement construction and roofing membrane manufacture. However, bitumen properties and mechanical behaviour are highly influenced by temperature and externa! agents, which may lead to severa! problems such as thermal cracking and rutting, and induce ageing processes, eventually provoking its premature failure. In an attempt to overcome such issues, bitumen has traditionally been modified by the use of different types of additives, commonly polymers like SBS, EVA, etc., which when added to bitumen and properly mixed, improve its mechanical properties. However, many different problems arise from their mutual thermodynamic incompatibility, which tend to provoke an eventual phase separation, with the subsequent loss of improvement in properties. Interestingly, chemical modification by means of reactive polymers has shown to be an effective way to noticeably enhance bitumen properties, and amongst reactive agents, polymeric MDI (a blend of diphenylmethane di-isocyanate and its higher homologues) has led to significant improvements in performance. Another type of material, layered silicates (clays), has centred the interest of both polymer and bitumen modifications, given the enhancement it may induce on their properties when interacting at the nanometre scale. Nanoclays are naturally occurring minerals, inherently inorganic, which might be nevertheless rendered organic if subjected to ion-exchange reactions with quaternary ammonium salts, hence resulting in increased compatibility with bitumen and polymers, allowing for their dispersion in clay layers to produce nanocomposites. Thus, targeting at high performance materials for civil engineering applications, the optimisation of the processing conditions that allow far the delamination of clay layers requires information on the materials' rheological properties. Accordingly, in this work, a further approach has been taken by preparing ternary bituminous composites consisting of an organically-modified montmorillonite clay, Closite 20A®, along with a reactive isocyanate-based oligomer, polymeric MDI. These two additives have been used to modify bitumen, both separately and jointly, resulting in bituminous systems that were studied in a twofold perspective. On the one hand, the influence exerted by different processing variables, such as shear and time, on the end properties. On the other hand, the effects of those variables when combined with the reactivity of isocyanate groups. Thus, investigation has focused on factors behind the formation of a nanoreinforced structure in bitumen/clay systems, so as to produce nanocomposites with improved thermo-mechanical performance; and to what extent the reactivity of isocyanate groups in ternary systems influenced such structure and performance. To proceed so, systems were subjected to a wide range of rheological tests, complemented by thermal, microstructural, and chemical studies. Consequently, a deeper insight has been taken into bitumen/clay nanocomposites, and to the best of our knowledge, a first approach into the characterisation of isocyanate modified bitumen/clay composites, and the influence of sorne majar controlling variables on their end properties. |
| publishDate |
2017 |
| dc.date.none.fl_str_mv |
2017 2017-01-01 2017 2017-01-01 |
| dc.type.none.fl_str_mv |
doctoral thesis http://purl.org/coar/resource_type/c_db06 |
| dc.type.openaire.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
| dc.identifier.none.fl_str_mv |
http://hdl.handle.net/10272/16092 |
| url |
http://hdl.handle.net/10272/16092 |
| dc.language.none.fl_str_mv |
Inglés eng |
| language_invalid_str_mv |
Inglés |
| language |
eng |
| dc.rights.none.fl_str_mv |
open access http://purl.org/coar/access_right/c_abf2 Atribución-NoComercial-SinDerivadas 3.0 España http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
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info:eu-repo/semantics/openAccess |
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open access http://purl.org/coar/access_right/c_abf2 Atribución-NoComercial-SinDerivadas 3.0 España http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
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openAccess |
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application/pdf |
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Universidad de Huelva |
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Universidad de Huelva |
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reponame:Arias Montano. Repositorio Institucional de la Universidad de Huelva instname:Universidad de Huelva (UHU) |
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Universidad de Huelva (UHU) |
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Arias Montano. Repositorio Institucional de la Universidad de Huelva |
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Arias Montano. Repositorio Institucional de la Universidad de Huelva |
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1869414993686953984 |
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Novel organoclay/isocyanate-based modification of bitumen for the development of high-performance compositesOrtega Bravo, Francisco JoséMateriales bituminososPolímerosReologíaNanoclayIsocyanateBitumenRheologyCompositeNanoarcillaIsocianatoBetúnReologíaBitumen, by-product resulting from the vacuum distillation of crude oíl, consists of a complex mixture of organic and inorganic compounds, comprising mainly aliphatic, aromatic and naphthenic hydrocarbons. Even though its composition greatly depends on the crude oíl source and the refining process, a basic characterisation can be performed based on its solubility in n-alkanes, resulting in maitenes, further subdivided into saturates, aromatics and resins; and asphaltenes, which constitute the most polar fraction of bltumen. This separation configures the so-called SARAs fractions of bitumen. Amongst bitumen properties, waterproofing, ductility, adhesiveness, and resistance to weathering and chemicals have favoured its development for a wide range of applications, mainly in the fields of pavement construction and roofing membrane manufacture. However, bitumen properties and mechanical behaviour are highly influenced by temperature and externa! agents, which may lead to severa! problems such as thermal cracking and rutting, and induce ageing processes, eventually provoking its premature failure. In an attempt to overcome such issues, bitumen has traditionally been modified by the use of different types of additives, commonly polymers like SBS, EVA, etc., which when added to bitumen and properly mixed, improve its mechanical properties. However, many different problems arise from their mutual thermodynamic incompatibility, which tend to provoke an eventual phase separation, with the subsequent loss of improvement in properties. Interestingly, chemical modification by means of reactive polymers has shown to be an effective way to noticeably enhance bitumen properties, and amongst reactive agents, polymeric MDI (a blend of diphenylmethane di-isocyanate and its higher homologues) has led to significant improvements in performance. Another type of material, layered silicates (clays), has centred the interest of both polymer and bitumen modifications, given the enhancement it may induce on their properties when interacting at the nanometre scale. Nanoclays are naturally occurring minerals, inherently inorganic, which might be nevertheless rendered organic if subjected to ion-exchange reactions with quaternary ammonium salts, hence resulting in increased compatibility with bitumen and polymers, allowing for their dispersion in clay layers to produce nanocomposites. Thus, targeting at high performance materials for civil engineering applications, the optimisation of the processing conditions that allow far the delamination of clay layers requires information on the materials' rheological properties. Accordingly, in this work, a further approach has been taken by preparing ternary bituminous composites consisting of an organically-modified montmorillonite clay, Closite 20A®, along with a reactive isocyanate-based oligomer, polymeric MDI. These two additives have been used to modify bitumen, both separately and jointly, resulting in bituminous systems that were studied in a twofold perspective. On the one hand, the influence exerted by different processing variables, such as shear and time, on the end properties. On the other hand, the effects of those variables when combined with the reactivity of isocyanate groups. Thus, investigation has focused on factors behind the formation of a nanoreinforced structure in bitumen/clay systems, so as to produce nanocomposites with improved thermo-mechanical performance; and to what extent the reactivity of isocyanate groups in ternary systems influenced such structure and performance. To proceed so, systems were subjected to a wide range of rheological tests, complemented by thermal, microstructural, and chemical studies. Consequently, a deeper insight has been taken into bitumen/clay nanocomposites, and to the best of our knowledge, a first approach into the characterisation of isocyanate modified bitumen/clay composites, and the influence of sorne majar controlling variables on their end properties.El betún, subproducto de la destilación al vacío del crudo de petróleo, está constituido por una mezcla compleja de compuestos orgánicos e inorgánicos, principalmente de hidrocarbonos alifáticos, aromáticos y nafténicos. Aunque su composición depende en gran medida del origen del crudo y del proceso de refino utilizado, ésta se suele definir en base a la solubilidad en n-alcanos, resultando en la separación en maltenos, que se subdividen a su vez en saturados, aromáticos y resinas; y en asfaltenos, que constituyen la fracción más polar del betún. Esta clasificación establece las denominadas fracciones 5ARAs del betún. Entre las propiedades del betún, la impermeabilidad, ductilidad, adhesividad, y la resistencia a la climatología y a agentes químicos han favorecido su desarrollo para un amplio rango de aplicaciones, principalmente en los terrenos de la pavimentación y de las membranas impermeabilizantes. Sin embargo, la temperatura y otros agentes externos influyen en gran medida sobre dichas propiedades y el comportamiento mecánico del betún, lo que puede producir problemas, como deformaciones y grietas, así como inducir procesos de envejecimiento, provocando su fallo prematuro. Con objeto de superar tal problemática, el betún se ha modificado tradicionalmente con diversos aditivos, generalmente polímeros como el SBS, EVA, etc., que mejoran sus propiedades mecánicas cuando se mezclan adecuadamente. No obstante, la cierta incompatibilidad termodinámica existente entre ambos puede conllevar a la separación de las fases, deteriorando las propiedades. En este sentido, la modificación química por medio de polímeros reactivos ha mostrado ser una técnica efectiva para la mejora de las propiedades, entre los que el uso de MDI polimérico (mezcla de diisocianato de difenilmetano y homólogos superiores) permite mejoras significativas. otro tipo de material, los silicatos laminados (arcillas), ha centrado el interés de la modificación de polímeros y betunes, dada la mejora que puede producir cuando interacciona a escala nanométrica. Las nanoarcillas son minerales naturales inorgánicos que se pueden modificar mediante reacciones de intercambio iónico con sales de amonio cuaternario, permitiendo su conversión en organofílicos, lo que favorece su compatibilidad y la separación de sus capas para producir nanocomposites. Así, la producción de materiales de alto rendimiento para ingeniería civil implica la optimización de las condiciones de procesado para que posibiliten la separación de las láminas, lo que requiere información sobre las propiedades reológicas. De esta forma, en este trabajo, se ha abordado la modificación del betún mediante la preparación de composites bituminosos ternarios con una montmorillonita organomodificada, Cloisite 20A®, y un oligómero reactivo de base isocianato, MDI polimérico. Estos dos aditivos se usaron por separado y conjuntamente, estudiándose sus efectos desde una perspectiva dual. Por una parte, la influencia ejercida por diferentes variables de procesado, como la cizalla y el tiempo, sobre las propiedades finales. Y por otra parte, los efectos de estas variables en combinación...con.la reactividad de losaruoos. isocianato. Así, la investigación se ha enfocado a los factores que influyen en la formación de una estructura nanoreforzada para dar lugar a nanocomposites con un comportamiento termomecánico mejorado; y en el nivel de influencia que ejerce la reactividad de los grupos isocianato sobre dicha estructura y el comportamiento del material. Para ello, los sistemas se sometieron a numerosos ensayos reológicos, complementados por estudios térmicos, micro-estructurales y químicos. Por tanto, ello constituye una profundización en el conocimiento sobre los nanocomposites de betún y arcilla, y de cuanta constancia se tiene, una primera incursión en la caracterización de aquellos modificados con isocianatos, y en la influencia que ejercen algunas de las principales variables de procesado sobre sus propiedades finales.Universidad de HuelvaNavarro Domínguez, Francisco JavierGarcía Morales, MoisésUniversidad de Huelva. Departamento de Ingeniería Química, Química Física y Ciencias de los Materiales20172017-01-0120172017-01-01doctoral thesishttp://purl.org/coar/resource_type/c_db06info:eu-repo/semantics/doctoralThesisapplication/pdfhttp://hdl.handle.net/10272/16092reponame:Arias Montano. Repositorio Institucional de la Universidad de Huelvainstname:Universidad de Huelva (UHU)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2Atribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/info:eu-repo/semantics/openAccessoai:ariasmontano.uhu.es:10272/160922026-06-02T14:58:11Z |
| score |
15.812429 |