Materiales poliméricos compuestos obtenidos a partir de los residuos generados por la agroindustria de la caña de azúcar. Una alternativa adicional. II
Fecha
2008
Autores
Jose-Roberto, Vega-Baudrit
Delgado-Montero, Karina
Sibaja Ballestero, María
Alvarado Aguilar, Patricia
Título de la revista
ISSN de la revista
Título del volumen
Editor
Universidad del País Vasco (España)
Resumen
En trabajos previos, en los que se ha utilizado residuos generados por la
agroindustrialización de la caña de azúcar, se determinó que la utilización de un 70 % de melaza
de caña de azúcar como sustituyente parcial del PEG-300, reactivo utilizado para la preparación de
espumas de poliuretano, generaba propiedades mecánicas adecuadas, así como una densidad
aparente acorde a lo requerido. En esta investigación se emplearon los resultados obtenidos en la
preparación de poliuretanos con melaza de caña de azúcar y se reforza ron con fibra del bagazo de
la caña de azúcar para obtener un material compuesto.
Inicialmente se caracterizó física y químicamente la fibra molida de bagazo de la caña de
azúcar, mediante análisis de humedad, cenizas, contenidos de a-celulosa, de hemicelulosa y de
lignina, así como extractos acuosos y orgánicos. Los valores más representativos correspondieron
a la a-celulosa (47,3%), a la lignina (24,4%) y a la holocelulosa (66,1% ).
Posteriormente, se prepararon espumas de poliuretano con la fibra natural como refuerzo.
Se utilizaron cuatro diferentes porcentajes de fibra molida 5, 10, 15, 20% (p/p) con un tamaño de
partícula de 60 mallas; se utilizó una mezcla PEG-Melaza en una relación de 30:70% (p/p),
difenilmetildiisocianato (MDI) y dibutil dilaurato de estaño como catalizador. Los materiales
compuestos sintetizados fueron caracterizados mediante la determinación de la densidad aparente,
se realizaron análisis térmicos por termogravimetría -TGA y mecánicos de compresión. Asimismo,
se sintetizó espuma de poliuretano de referencia, la cual no contenía el bagazo de caña de azúcar.
De los resultados obtenidos en la caracterización de las espumas de poliuretano, se
observó que la muestra con 10% de fibra de caña de azúcar presentaba la menor densidad aparente.
Asimismo, en los anális is térmicos se observó una tendencia general a disminuir tanto la
temperatura inicial de descomposición como la temperatura a la máxima velocidad de
degradación, comparada con la espuma de referencia. Finalmente, las pruebas mecánicas
mostraron un valor má ximo tanto en el esfuerzo a la compresión como en el módulo, en la muestra
que contiene 10% de fibra de bagazo de caña de azúcar.
De lo anterior se concluye que la utilización de los desechos de la actividad agroindustrial
de la caña de azúcar, permite elaborar materiales compuestos con propiedades adecuadas a las
aplicaciones requeridas. Las espumas de poliuretano sintetizadas con la sustitución parcial del
PEG por la melaza y reforzadas con el bagazo de caña de azúcar, pueden ser utilizadas en la
industria del embalaje; en este caso, los materiales se emplean por periodos cortos, y por lo general
son muy voluminosos, poco densos. Así, el uso de este tipo de espuma es muy adecuado porque
además de que los materiales empleados en su síntesis son de fácil adquisición y de bajo costo, el
material adquiere características de ser potencialmente biodegradable, y se da un uso más
adecuado a los materiales considerados como residuos.
In previous work, which has been used waste generated by the agro-industrialization of sugar cane, it was determined that the use of 70% of sugar cane molasses generated adequate mechanical properties and a bulk density consistent with what is required. In this research, results were used in the preparation of polyurethanes with sugar cane molasses; finally they were reinforced with fiber bagasse from sugar cane to produce a composite material. Initially, fiber of milled bagasse was characterized physically and chemically. It was obtained the contents of a-cellulose, moisture, ashes, hemicelluloses and lignin, as well as organic and aqueous extracts. The most representatives values were a-cellulose (47.3%), lignin (24.4%) and hollocelulose (66.1%). Subsequently, polyurethane foams were prepared with the natural fiber as reinforcement. It was used four different percentages of fiber ground 5, 10, 15, 20% (w /w) with a particle size of 60 mesh, it was used a PEG-molasses mixture in a ratio of 30:70% (w/w), diphenylmethane diisocyanate (MDI) and dibutyltin dilaurate as a catalyst. Composite materials synthesized were characterized by determining the bulk density, thermal analyses (thermogravimetry-TGA ) and mechanical compression. Also, it was synthesized reference polyurethane foam. The results showed that the sample with 10% of sugar cane fiber had the lowest bulk density. Also, in the thermal analysis showed a general trend to reduce both the initial temperature of decomposition as the temperature at the maximum rate of degradation, compared with the foam reference. Finally, the mechanical tests showed a maximum value in the effort to compression as in the module, in the sample containing 10% fiber sugar cane bagasse. It was concluded that the use of agro-industrial waste from the activity of sugar cane, lets develop composite materials with properties suitable for applications required. The polyurethane foam synthesized with the partial replacement of PEG for molasses and reinforced with sugar cane bagasse, can be used in the packaging industry, in this case, materials are used for short periods, and are usually very bulky, little dense. So, using this type of foam is very appropriate because in addition to the materials used in its synthesis are easy and inexpensive purchases , the material acquired characteristics to be potentially biodegradable, and is better use of materials regarded as waste.
In previous work, which has been used waste generated by the agro-industrialization of sugar cane, it was determined that the use of 70% of sugar cane molasses generated adequate mechanical properties and a bulk density consistent with what is required. In this research, results were used in the preparation of polyurethanes with sugar cane molasses; finally they were reinforced with fiber bagasse from sugar cane to produce a composite material. Initially, fiber of milled bagasse was characterized physically and chemically. It was obtained the contents of a-cellulose, moisture, ashes, hemicelluloses and lignin, as well as organic and aqueous extracts. The most representatives values were a-cellulose (47.3%), lignin (24.4%) and hollocelulose (66.1%). Subsequently, polyurethane foams were prepared with the natural fiber as reinforcement. It was used four different percentages of fiber ground 5, 10, 15, 20% (w /w) with a particle size of 60 mesh, it was used a PEG-molasses mixture in a ratio of 30:70% (w/w), diphenylmethane diisocyanate (MDI) and dibutyltin dilaurate as a catalyst. Composite materials synthesized were characterized by determining the bulk density, thermal analyses (thermogravimetry-TGA ) and mechanical compression. Also, it was synthesized reference polyurethane foam. The results showed that the sample with 10% of sugar cane fiber had the lowest bulk density. Also, in the thermal analysis showed a general trend to reduce both the initial temperature of decomposition as the temperature at the maximum rate of degradation, compared with the foam reference. Finally, the mechanical tests showed a maximum value in the effort to compression as in the module, in the sample containing 10% fiber sugar cane bagasse. It was concluded that the use of agro-industrial waste from the activity of sugar cane, lets develop composite materials with properties suitable for applications required. The polyurethane foam synthesized with the partial replacement of PEG for molasses and reinforced with sugar cane bagasse, can be used in the packaging industry, in this case, materials are used for short periods, and are usually very bulky, little dense. So, using this type of foam is very appropriate because in addition to the materials used in its synthesis are easy and inexpensive purchases , the material acquired characteristics to be potentially biodegradable, and is better use of materials regarded as waste.
Descripción
Palabras clave
POLIURETANO, MELAZA, BIODEGRADABLE, ESPUMAS DE POLIURETANO, AZÚCAR, POLYURETHANES, BIODEGRADABLE, MOLASSES, POLYURETHANE FOAMS, SUGAR, AGROINDUSTRIA