Obtención de compuestos de caucho de etileno-propileno-dieno con contenido de grafeno y óxido de bismuto(III): Estudio de propiedades físicas y mecánicas.
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Date
2024
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Universidad de Concepción
Abstract
En este trabajo se investigó el uso de nanomateriales usados cómo relleno en un caucho de etileno-propileno-dieno, lo que permite obtener nanocompósitos elastoméricos de propiedades mecánica mejoradas de resistencia y con propiedades de blindaje a la radiación electromagnética de alta energía, tales como los rayos gamma. Los nanomateriales usados corresponden a nanoplaquetas de grafeno y nanopartículas de óxido de bismuto(III). Estos fueron adicionados a la matriz de etileno-propileno-dieno (EPDM) separada o conjuntamente.
El uso de nanoplaquetas de grafeno como material de relleno se fundamenta en sus excelentes propiedades mecánicas y que imparte resistencia adicional a compuestos de caucho. Respecto a las nanopartículas de óxido de bismuto(III) es debido a la presencia de bismuto que es un elemento de alto número atómico (Z = 83) que promueve la ocurrencia de procesos de absorción y dispersión de la radiación gamma, impartiendo propiedades de blindaje al nanocompósito en base de EPDM. Adicionalmente, se estudió el efecto de polietilenglicol (PEG) para promover la dispersión homogénea de las nanopartículas.
Se prepararon las muestras en un mezclador abierto de dos rodillos por 20 minutos a temperatura ambiente y luego se procesaron por 30 minutos en un reómetro de troquel móvil a 180°C. Se realizaron ensayos de tracción, dureza, se calculó el índice de resistencia a la abrasión, y se caracterizaron las muestras por FT-IR, TGA, DTG y SEM. Se analizó el coeficiente de atenuación lineal, el coeficiente de atenuación en masa y el peso atómico promedio para determinar sus propiedades de atenuación.
Se demostró que la presencia del PEG 1500 mejora la dispersión del material de relleno y que disminuye el tiempo de vulcanización, lo que se atribuyó a
que este promueve el proceso de vulcanización. Además, se demostró que los compositos con óxido de bismuto(III) poseen propiedades de atenuación a la radiación gamma de 75% para un nanocompósito en base de EPDM y óxido de bismuto(III). En el caso de EDPM con contenido de óxido de bismuto(III), nanoplaquetas de grafeno y polietilen glicol se alcanzó una mejora de 61% comparado a EPDM sin relleno. Las imágenes SEM revelan zonas de segregación en los compuestos con grafeno disminuyendo las capacidades de atenuación ya que dificulta la distribución de las nanopartículas de óxido de bismuto(III) en los compositos. Finalmente se determina que la presencia del PEG 1500 ayuda en la compatibilización de los rellenos con la matriz polimérico, mejorando la dispersión de estos en las mezclas obtenidas.
In this work, the use of nanomaterials as filler in ethylene-propylene-diene rubber was investigated, which allows obtaining elastomeric nanocomposites with improved mechanical resistance properties and shielding properties to high-energy electromagnetic radiation, such as gamma rays. The nanomaterials used correspond to graphene nanoplatelets and bismuth(III) oxide nanoparticles. These were added to the ethylene-propylene-diene matrix (EPDM) separately or together. The use of graphene nanoplatelets as a filler material is based on their excellent mechanical properties and that they impart additional resistance to rubber compounds. Regarding bismuth(III) oxide nanoparticles, it is due to the presence of bismuth, which is an element with a high atomic number (Z = 83) that promotes the occurrence of absorption and dispersion processes of gamma radiation, imparting shielding properties to the EPDM-based nanocomposite. Additionally, the effect of polyethylene glycol (PEG) to promote the homogeneous dispersion of the nanoparticles was studied. Samples were prepared in a two-roll open mixer for 20 minutes at room temperature and then processed for 30 minutes in a moving die rheometer at 180 °C. Tensile and hardness tests were carried out, the abrasion resistance index was calculated, and the samples were characterized by FT-IR, TGA, DTG and SEM. The linear attenuation coefficient, mass attenuation coefficient, and average atomic weight were analyzed to determine their attenuation properties. It was shown that the presence of PEG 1500 improves the dispersion of the filler material and decreases the vulcanization time, which was attributed to The fact that it promotes the vulcanization process. Furthermore, it was demonstrated that composites with bismuth(III) oxide have gamma radiation attenuation properties of 75% for a nanocomposite based on EPDM and bismuth(III) oxide. In the case of EDPM containing bismuth(III) oxide, graphene nanoplatelets and polyethylene glycol, an improvement of 61% was achieved compared to EPDM without filler. The SEM images reveal segregation zones in the composites with graphene, decreasing the attenuation capacities since it makes difficult the distribution of the bismuth(III) oxide nanoparticles in the composites. Finally, it is determined that the presence of PEG 1500 helps in making the fillers compatible with the polymer matrix, improving their dispersion in the obtained mixtures.
In this work, the use of nanomaterials as filler in ethylene-propylene-diene rubber was investigated, which allows obtaining elastomeric nanocomposites with improved mechanical resistance properties and shielding properties to high-energy electromagnetic radiation, such as gamma rays. The nanomaterials used correspond to graphene nanoplatelets and bismuth(III) oxide nanoparticles. These were added to the ethylene-propylene-diene matrix (EPDM) separately or together. The use of graphene nanoplatelets as a filler material is based on their excellent mechanical properties and that they impart additional resistance to rubber compounds. Regarding bismuth(III) oxide nanoparticles, it is due to the presence of bismuth, which is an element with a high atomic number (Z = 83) that promotes the occurrence of absorption and dispersion processes of gamma radiation, imparting shielding properties to the EPDM-based nanocomposite. Additionally, the effect of polyethylene glycol (PEG) to promote the homogeneous dispersion of the nanoparticles was studied. Samples were prepared in a two-roll open mixer for 20 minutes at room temperature and then processed for 30 minutes in a moving die rheometer at 180 °C. Tensile and hardness tests were carried out, the abrasion resistance index was calculated, and the samples were characterized by FT-IR, TGA, DTG and SEM. The linear attenuation coefficient, mass attenuation coefficient, and average atomic weight were analyzed to determine their attenuation properties. It was shown that the presence of PEG 1500 improves the dispersion of the filler material and decreases the vulcanization time, which was attributed to The fact that it promotes the vulcanization process. Furthermore, it was demonstrated that composites with bismuth(III) oxide have gamma radiation attenuation properties of 75% for a nanocomposite based on EPDM and bismuth(III) oxide. In the case of EDPM containing bismuth(III) oxide, graphene nanoplatelets and polyethylene glycol, an improvement of 61% was achieved compared to EPDM without filler. The SEM images reveal segregation zones in the composites with graphene, decreasing the attenuation capacities since it makes difficult the distribution of the bismuth(III) oxide nanoparticles in the composites. Finally, it is determined that the presence of PEG 1500 helps in making the fillers compatible with the polymer matrix, improving their dispersion in the obtained mixtures.
Description
Tesis para optar al grado académico de Magíster en Ciencias mención en Química
Keywords
Caucho, Etileno, Grafeno, Bismuto