Estudio de la Cera Carnauba como Compatibilizante en Mezclas Poli (ácido láctico)-Almidón de Achira (Canna edulis)

Silva, Myrian1; Encalada, Katherine1; Valle, Vladimir1

1Escuela Politécnica Nacional, Facultad de Ingeniería Química y Agroindustria, Quito, Ecuador

Resumen: La marcada diferencia en la afinidad del poli (ácido láctico) (PLA) y almidón requiere la búsqueda de nuevas alternativas de compatibilizantes no tóxicos, es así que el objetivo de la presente investigación es evaluar la miscibilidad de mezclas de PLA-almidón de achira-glicerol a diferentes concentraciones (1-5 %) de cera carnauba. Las mezclas fueron procesadas en una cámara de mezclado a 120 °C, durante 20 min, a velocidad de giro de 90 rpm; posteriormente fueron prensadas a 120 °C y 21 MPa durante 10 min. Los resultados, evaluados a través de microscopía óptica y ensayos mecánicos, mostraron la factibilidad del uso de este compatibilizante, obteniéndose mayor homogeneidad de las mezclas al emplearse 1% de cera carnauba. Se concluyó que el tamaño y distribución de las heterogeneidades existentes en el material provocó concentradores de tensiones que a su vez provocaron elevada variabilidad en las propiedades mecánicas estudiadas.

Palabras clave: Poli(ácido láctico), Almidón de achira, Cera carnauba, Miscibilidad.

Study of Carnauba Wax as Compatibilizer in Polylactide-Achira Starch (Canna edulis) blends

Abstract: The huge difference in terms of affinity between polylactide (PLA) and starch demands to find new alternatives of non- toxic compatibilizers. In this sense, the present paper aims to evaluate the miscibility of PLA, achira starch and glycerol at different amounts of carnauba wax (1-5 %). The methodology consisted of mixing the components into a rheometer at 120 ° C, for 20 min at a rotational speed of 90 rpm, then they were pressed at 120 °C and 21 MPa during 10 min. The results obtained throughout optical microscopy and mechanical test, shown a feasible use of carnauba wax as compatibilizer of this blend. Additionally, the highest homogeneity was obtained while the compatibilizer were at 1%. In conclusion, the size and distribution of heterogeneities presented over the material caused stress concentrators which resulted in an important variability over the mechanical properties.

Keywords: Polylactide, Achira starch, Carnauba wax, Miscibility.

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