Curaua fiber reinforced high-density polyethylene composites: effect of impact modifier and fiber loading

Jaqueline Albano de Morais,Marco-Aurelio De Paoli,Renan Gadioli

doi:10.1590/0104-1428.2124

Jaqueline Albano de Morais, Marco-Aurelio De Paoli + Show 1 more

Open Access

https://doi.org/10.1590/0104-1428.2124

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Abstract

Short fibers are used in thermoplastic composites to increase their tensile and flexural resistance; however, it often decreases impact resistance. Composites with short vegetal fibers are not an exception to this behavior. The purpose of this work is to produce a vegetal fiber reinforced composite with improved tensile and impact resistance in relation to the polymer matrix. We used poly(ethylene-co-vinyl acetate), EVA, to recover the impact resistance of high density polyethylene, HDPE, reinforced with Curaua fibers, CF. Blends and composites were processed in a corotating twin screw extruder. The pure polymers, blends and composites were characterized by differential scanning calorimetry, thermogravimetry, infrared spectroscopy, scanning electron microscopy, tensile mechanical properties and Izod impact resistance. EVA used as impact modifier in the HDPE matrix exhibited a co-continuous phase and in the composites the fibers were homogeneously dispersed. The best combination of mechanical properties, tensile, flexural and impact, were obtained for the formulations of composites with 20 wt. % of CF and 20 to 40 wt. % of EVA. The composite prepared with 20 wt. % EVA and containing 30 wt. % of CF showed impact resistance comparable to pure HDPE and improved tensile and flexural mechanical properties.

Highlights

Vegetal fibers are largely replacing other reinforcing coupling agent provided a better fiber to matrix interaction.agents for thermoplastic and thermoset composites, because Like in other polymer/fiber composites, tensile and flexural they are produced from renewable resources, have high mechanical properties improvement is a consequence of toughness, have low density and are biodegradable[1]. stress transference to the fiber, provided by a good fiberTheir use produces composites with increased tensile and to matrix adhesion
The vegetal fibers used in this work, Curauá fibers, High-density polyethylene, HDPE, has a high impact resistance, when reinforced with vegetal fibers this resistance decreases by ca. 30%[13]
The Tm of the HDPE phase in the blends did not change with increased contents of EVA, in relation to pure HDPE

Summary

Introduction

Vegetal fibers are largely replacing other reinforcing coupling agent provided a better fiber to matrix interaction.agents for thermoplastic and thermoset composites, because Like in other polymer/fiber composites, tensile and flexural they are produced from renewable resources, have high mechanical properties improvement is a consequence of toughness, have low density and are biodegradable[1]. stress transference to the fiber, provided by a good fiberTheir use produces composites with increased tensile and to matrix adhesion. Agents for thermoplastic and thermoset composites, because Like in other polymer/fiber composites, tensile and flexural they are produced from renewable resources, have high mechanical properties improvement is a consequence of toughness, have low density and are biodegradable[1]. Stress transference to the fiber, provided by a good fiber Their use produces composites with increased tensile and to matrix adhesion. This improvement occurs in flexural mechanical properties in comparison to the matrix parallel to a decrease in the impact resistance, as generally polymer. Like other lignocellulosic proportions and processed by two different methods[14]

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