Mejoramiento de las Propiedades de Tensión en WPC de LDPE: HIPS/Fibra Natural Mediante Entrecruzamiento con DCP

Abstract

Resumen: Fibra de Retamo Liso (telinemonspessulana) fue mezclada en una matriz polimérica formada por: polietileno de baja densidad (LDPE) y poliestireno de alto impacto (HIPS) en relación 70:30 respectivamente. La fibra natural fue sometida a reducción de tamaño entre 1700 y 850 µm; se le realizó tratamiento superficial de mercerización; el contenido de humedad fue 0,17%. El análisis termo gravimétrico (TGA) muestra que la fibra tratada tiene estabilidad de 200,53 °C. La elaboración del compuesto se realizó en mezclador interno y la técnica de obtención de las probetas fue mediante moldeo por compresión. Se evaluó el efecto del agente entrecruzante peróxido de dicumilo (DCP) en compuestos con varios porcentajes de fibra: 0; 10; 25; 50 phr. La adición de DCP (1 phr) en los compuestos, mejora significativamente las propiedades de tensión con respecto a similares concentraciones de fibra; sin embargo, esta diferencia en los valores de las propiedades disminuye progresivamente cuando la cantidad de fibra se aproxima a 50 phr. El aumento en la concentración de fibra afecta negativamente las propiedades de tensión, con excepción del Módulo de Elasticidad y la Resistencia a la Fluencia. La causa principal es originada por la baja adhesión interfacial fibra natural-matriz polimérica, claramente evidenciada en las imágenes SEM. Palabras-clave: TelineMonspessulana, compuesto de plástico y madera (WPC), polietileno de baja densidad, poliestireno de alto impacto, peróxido de dicumilo. Abstract: Straight Retamo Fiber (telinemonspessulana) was mixed in a polymer matrix formed by low density polyethylene (LDPE) and high impact polystyrene (HIPS) in a 70:30 ratio. The natural fiber was subjected to size reduction between 1700 and 850 µm; surface treatment mercerization was performed; the moisture content was 0.17%. The thermo gravimetric analysis (TGA) showed that the treated fiber has stability at 200.53 °C. The preparation of the compound was performed in an internal mixer with the samples being obtained by compression molding. The effect of crosslinking agent was evaluated: dicumyl peroxide (DCP) in compounds with various percentages of fiber: 0; 10; 25; 50 phr. The addition of DCP (1 phr) in the compounds significantly improved tensile properties compared to similar concentrations of fiber; however, this difference in property values progressively decreased when the amount of fiber approximated 50 phr. The increase in fiber concentration negatively affected the tensile properties, except for the modulus of elasticity and fluence resistance. The main cause is the low interfacial adhesion between the natural fiber and the polymer matrix, clearly evidenced in the SEM images.

Evaluation of silanes in SBR 1502 / Telinne Monspessulana flour composites

“…The fractured surface of the specimens under tensile strength were observed by scanning electron microscopy (SEM), the procedure was performed following the methodology used by Tobón et al [17] .…”

“…Similarly in Figure 4b forming grafts shown in APTES with TMF-untreated compound, precisely this specimen showed the highest tensile strenght value when the amino silane is used. This could mean that there was no competition between the silane coupling reactions with the flour and the crosslinking reaction of the polymer chains with DCP [17][18][19] . When comparing the two silanes difference in values was observed between them, it shows that the percentage of gel APTES was higher independent of the method of addition.…”

Influence of Coconut Shell Addition on Physico-Mechanical Properties of Wood Plastic Composites1

“…With respect to the coupling agents, Tobón et al (2014) incorporated Teline monspessulana (L.) O. Bolós and Vigo fibers in the mixture of LDPE and high impact polystyrene (HIPS), in order to evaluate the efficiency of the coupling agent dicumyl peroxide (DCP) in this composite type. It was verified that the mixture of LDPE and HIPS had a negative effect on the composites mechanical properties due to the lack of crosslinks.…”