Characterization of raffia palm fiber for use in polymer composites

Abstract

Raffia palm fibers are potential reinforcement materials for making cost-effective polymer-based composite. This paper presents the results obtained from a study of physical, chemical, thermal and mechanical properties of raffia palm fibers (RPFs) derived from the raffia palm tree (Raphia farinifera). The as-received RPFs had their remnant binders manually removed and was subsequently cleaned in a 2% detergent solution before drying in an air oven at 70 °C for 24 h. Evaluation of the properties of the dried samples was carried out using a combination of characterization techniques including chemical composition determination, density measurement, moisture adsorption and water absorption measurements, tensile testing, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Raman spectroscopy, X-ray diffractometry, and Fourier transform infrared spectromicroscopy. The main constituents of RPFs were found to be cellulose, hemicellulose and lignin. The average diameter and average density were 1.53 ± 0.29 mm and 1.50 ± 0.01 g/cm 3 , respectively. The average breaking strength of the fibers ranged from 152 ± 22 to 270 ± 39 MPa; it did not vary significantly with fiber length and cross-head speed during tensile testing. The results of scanning electron microscopic investigation of the fibers showed that they comprise several elemental fibers which are tightly packed together with each having its own lumen. Synchrotron-based Fourier-transform infrared spectromicroscopy of a cross-section of the fiber showed that lignin is concentrated mostly on the outside while cellulose and pectin are concentrated in the mid-section. A two-stage water sorption behavior was observed for the fibers.

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

“…Similar behavior on tensile strength was observed in the present study, not caused by fiber content, but by the fiber length, which exhibited a higher decrease for composites with the shortest fibers ( Table 2). Although the raffia fiber has relatively high cellulose (53 wt%) and lignin (24 wt%) contents [28], which are responsible for its strength, Figure 8 indicates that this fiber acted only as filler into the polyester matrix. This may have occurred due to either an unsuitable processing of the composite or a weak interfacial fiber/matrix adhesion.…”

“…Although several studies on the use of NLFs as reinforcement in composites have been reviewed [1][2][3][4][5][6][7][8][9][10][11][12], relatively few papers on the potential use of raffia palm fibers in polymer composites were published so far. In fact, according to the Scopus database [26], in 2020 only 100 documents appear with the keywords "raffia" or "raphia" in the engineering and materials science subject areas [27][28][29][30]. This represents less than 8% of all publications on raffia, as shown in Figure 1.…”

“…The raffia nut is commonly used to extract oils for cosmetics. A kind of wine is produced from raffia sap, and its fibers are used for carpets, ropes, and handicrafts [28]. As a major producer of natural fibers and taking a unique position among South American countries, only recently in Brazil [31] have the raffia fibers from the Amazon region, also known as Jupati fiber, started to be considered as addition to polymer composites.…”

Procedure for Spaced Mesh Modeling from Digital Images: Example of the Leaf Sheath of the Coconut PalmCocos NuciferaL. (2D)

“…In this case, measuring instruments are used. Fiore et al evaluate the length of Arundo fibers after mechanical extraction using a ruler graduated in centimeters and millimeters It is the same for assessing the length of flax, yucca, and Nile rose fibers, − respectively. In addition, in other research, caliper − and micrometer − have been used to measure the diameter of the fibers under study. To evaluate these morphological characteristics, other authors have used non-contact techniques using optical instruments (binocular magnifier, optical microscope, and scanning electron microscope) to acquire images of the samples and image processing software (Image J, Motic Images, ArchiMed, and Leica) with which distance measurements are determined between two points positioned by the operator, and the areas are calculated for the surface delimited by the user. ,− …”

“…In addition, in other research, caliper − and micrometer − have been used to measure the diameter of the fibers under study.…”