Development and Characterization of Raffia Palm Fiber Reinforced Polymer Matrix Composites

Due to high energy consumption and environmental pollution generated in the processing and use of synthetic fibers, the need for replacement of these fibers with natural fibers in composites manufacture has increased. The advantages of natural fibers over synthetic fibers include low cost, biodegradability and non-toxicity. In this study, as received raffia palm fibers (RPF) and those whose surface were chemically modified using 10 wt.% NaOH for 5 h at 60oC and 0.6 M H2SO4 for 2 h at 100oC were compression molded to produce HDPE matrix composites containing 5, 10, 20, and 30 wt.% of RPFs. Morphological, thermal, tensile, physical and structural properties of the fibers before and after treatment were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), InstronTM machine and Fourier transform infrared spectroscopy (FTIRS). The effects of chemical treatments of the fiber and varying fiber loadings on the mechanical, physical and thermal properties of RPFs reinforced HDPE composites were investigated. Mechanical and thermal properties of the composites were investigated using InstronTM machine and the differential scanning calorimetry (DSC), respectively. The effect of chemical modification on water uptake of the composites was also studied. Surface chemical treatment of the RPFs by soaking in 10 wt.% NaOH for 5 h at 60oC or 0.6 M H2SO4 for 2 h at 100oC resulted in 22% increase in the cellulose content of the fiber. SEM results showed that the RPF comprises of several elemental fibers, which are tightly packed together with each having its lumen at the center. FTIR spectroscopy results indicated reduction and disappearance of some non-cellulosic components in the treated RPFs. Although, there was an increase in the degradation temperature of the treated fibers, tensile strength and water absorption capacity of the treated fibers reduced in comparison to non-treated fibers. The use of RPFs (surface treated or not) in reinforcing HDPE led to increase in tensile modulus, flexural strength, flexural modulus and crystallization temperature of the composite when compared to unreinforced HDPE. The rate of water absorption for composites containing treated fibers is lower than that for composites containing untreated fiber. The tensile strength, impact strength and melting temperature of HDPE decreased with addition of either untreated or treated RPFs. Results also showed that increasing fiber content decreased the tensile strength, flexural strength, impact energy and the melting temperature of the composites. However, increase in tensile modulus, flexural modulus, water absorption and crystallization temperature of the composites was observed as the fiber content was increased