Effect of Chemical Treatment and Length of Raffia Fiber (Raphia vinifera) on Mechanical Stiffening of Polyester Composites

Abstract

In recent decades, the unique characteristics of natural fibers have promoted their use as reinforcement in polymeric composites. This is verified in several industrial sectors, from packaging to automotive and civil construction. Among the natural fibers, the raffia fiber extracted from the palm tree Raphia vinifera and introduced in the Amazon region a long time ago; started to be considered for the production of polymeric composites only in recent years. For the first time, the effect of raffia fiber length and its alkali treatment on the mechanical properties of a polymer composite was disclosed. Tensile tests were performed in composites with raffia fibers randomly dispersed into terephthalate-based unsaturated polyester resin. The results showed an increase in the Young’s moduli, confirmed by ANOVA, for the composite with both untreated and alkali-treated fibers in comparison to the plain polyester, which characterizes a stiffening effect. The composites with alkali treated fibers exhibited similar tensile strength values for all lengths; however, their strengths are lower than those for the untreated condition due to a weak raffia fiber/polyester matrix adhesion. Therefore, this work fills the current knowledge gap on raffia fiber incorporation in polyester matrix and valorizes this abundant Brazilian resource, providing additional information towards the use of raffia fiber in polymer composites.

Effect of Raphia vinifera Fibre Size and Reinforcement Ratio on the Physical and Mechanical Properties of an Epoxy Matrix Composite: Micromechanical Modelling and Weibull Analysis

“…The fibres were mechanically extracted according to the method described by Njeugna et al [24] and then dried for 24 hours at a temperature of 105 °C as recommended by Baley et al [38] and Espinach et al [39] with vegetal fibres. Nine formulations were made based on combinations of three fibre lengths (5, 10, and 15 mm) [26] and three-volume fractions (20%, 30%, and 40%). To prepare the fibres, approximately eight fibres of 300 mm length were first grouped into batches, measured with a mm ruler, and marked to ensure uniformity of length.…”

“…The fibre efficiency factor for determining the theoretical tensile strength is defined by Equation ( 24) for l > l c and Equation ( 25) for l > l c . While the fibre efficiency factor for the determination of the tensile Young's modulus is given by Equation (26),…”

“…This work has shown that RVF can be used for the development of bio-composites [17] and the production of cellulose [25]. Work on the development of composites reinforced with RVF from sheets has shown that the addition of short, random fibres reduces the mechanical properties (modulus and strength) of the polyester matrix [26]. The use of RVF from the stem as a reinforcement of composite materials with regards to properties is therefore of great interest for the development of bio-composites [23,24].…”

Periquiteira (Cochlospermum orinocense): A Promising Amazon Fiber for Application in Composite Materials

“…When compared to synthetic fibers, NLFs are generally lighter, cheaper and have specific properties for similar applications [11][12][13][14][15][16][17][18][19][20][21][22], in addition to being environmentally friendly. These properties may vary according to the chemical composition and physical characteristics of the fibers.…”

Evaluation of Hot Pressing Processing by Physical Properties of Ecofriendly Composites Reinforced by Eucalyptus Sawdust and Chamotte Residues

“…Agro-industrial residues have the potential to be used as raw material for energy production, [2][3][4][5][6][7]. In general, new research with unknown lignocellulosic natural fibers is continuing discovering their potential to be used in engineering materials [8][9][10][11][12].…”