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Nowadays, fiber-reinforced composites have gained attention due to their improved potential for replacing the conventional materials in various applications. Kenaf fiber has been widely used as reinforcement in composites over the past few years which is a most attractive alternative due to its rapid growth at different climatic conditions and ensuring low cost; kenaf fiber has gained some attention to replacing the glass fiber composite and making it purely an eco-friendly composite. However, for enhancing its properties in different applications, an appropriate characterization is very important. Hence, many researches have been conducted in recent years, for the characterization of kenaf fiber and its composites. In this paper, a state-of-the-art review of these characterizations is presented. [ABSTRACT FROM AUTHOR]

Natural fiber-reinforced polymer matrix composites have been increasingly used in automotive and other fields because of their good mechanical properties, low density, excellent damping properties and biodegradability. The objective of this work is to develop and characterize a high-performance lightweight kenaf fiber composite that is processed using unconventional processing methods, wet laid process followed with compression molding process. Kenaf fiber mats produced by wet laid process are stacked with high-density polyethylene films and compression molded into plates from which testing samples are prepared. The effects of fiber length, fiber content, and area density on the tensile properties are investigated. The composite samples with the best tensile properties are also evaluated in its flexural, compression, impact, and fire resistance performance. The processing–structure–property relations of the developed kenaf fiber high-density polyethylene composite are systematically studied, which can be broadly applied to other natural fiber composites. [ABSTRACT FROM AUTHOR]

This article reports the preparation and characterization of newly developed hybrid composites consisting of epoxy resin (EP) matrix, acetylated kenaf bast fiber (AKF) and conducting polyaniline (PANI) nanowires. Initially, the EP/AKF composites were prepared by varying the AKF loading (5–30 wt%). The EP/AKF displayed an optimum tensile strength at 20 wt% AKF loading which was higher than that of untreated kenaf fiber EP composites (EP/UKF). The hybrid composites of EP/AKF/PANI were then prepared by using 20 wt% AKF loading with PANI inclusions from 2 to 14 wt%. The addition of PANI into EP/AKF induced positive electrical properties without considerably sacrificing its mechanical integrity. It was found that the electrical percolation threshold of these hybrid composites was at 11 wt% of PANI loading. PANI inclusions at above the percolation loading resulted in reduction of tensile and flexural strength. Meanwhile, no significant mechanical loss was observed below the threshold. The fracture morphological analysis revealed the occurrences of PANI nanowires pull out from the matrix. The Fourier transform infrared spectroscopy showed that the PANI component still maintained its doped condition inside the EP/20AKF. Water absorption and thermal analysis indicate that the PANI incorporation induced lower water uptakes and greater thermal stability to the EP/20AKF, respectively. [ABSTRACT FROM PUBLISHER]

In this study, mechanical properties such as tensile characteristics, flexural characteristics, impact strengths, and hardness of kenaf/phenol-formaldehyde (PF), fiberfrax/PF, and kenaf/fiberfrax hybrid PF composites have been investigated as a function of fiber loading. Composite samples were prepared by mixing the fibers and resin in a mixing chamber for 5 min. The composite sheets were prepared by pressing fiber-resin material in a steel mold at 120°C for 30 min at 10MPa pressure. The test samples were cut from the composite sheets. At least five specimens were tested and mean value was taken for each composite according to ASTM standards. The reinforcing effects of kenaf and fiberfrax fibers were evaluated at various fiber loadings, that is, 19, 28, 36, 43, 52, and 62 vol.%. The hybrid effect of kenaf and fiberfrax fiber on the tensile, flexural, impact strengths, and hardness was also investigated for various ratios of kenaf/fiberfrax fiber loadings ranging between 1 : 0 and 0 : 1. Total fiber loading of the hybrid composites was 43 vol.%. The tensile, flexural strength, and hardness of the composites increased with increasing fiber loading up to 43 vol.% and decreased above this value for kenaf/PF composites. Impact strength of kenaf/PF composite showed a trend of increase with increasing fiber loading. The tensile and flexural strength of fiberfrax/ PF composites increased by incorporation of fiberfrax fiber up to 36 vol.% and decreased beyond this value. However, the maximum impact strength and hardness were obtained for 52 vol.% fiberfrax fiber loading. The tensile, flexural, and impact strength values of fiberfrax/PF composites were found to be lower compared to kenaf/PF composites. With addition of fiberfrax fiber, the tensile, flexural, and impact strengths of the kenaf/fiberfrax hybrid PF composites decreased linearly and the hardness of the composite increased. The maximum hardness value was obtained for 0.25 : 0.75 kenaf/fiberfrax ratio. [ABSTRACT FROM AUTHOR]

Hybrid composite of thermoplastic natural rubber (TPNR) reinforced with Hibiscus cannabinus, L fiber (kenaf fiber: KF) and short glass fiber (GF) were prepared via melt blending method using internal mixer, at various temperatures, speed and time. TPNR matrix is a blend of polypropylene (PP), liquid natural rubber (LNR) and natural rubber (NR) at a ratio of 70: 10: 20. Processing parameters were determined from the tensile strength based on fiber content with 50: 50 ratios of GF and KF. Using the optimum processing parameters, tensile test was carried out for reinforced TPNR-KF-GF hybrid composites (0-20% by volume), with and without addition of silane coupling agent and maleic anhydride grafted polypropylene (MAPP). The result of tensile strength has shown that the increasing in kenaf fiber content substantially reduced the tensile strength and modulus. Scanning electron microscopy (SEM) has shown that the composite, with coupling agent or compatibilizer, promotes better fiber-matrix interaction. [ABSTRACT FROM AUTHOR]

Kenaf fiber (KF) based thermoplastic natural rubber (TPNR) composite was produced by melt blending with polypropylene (PP). Kenaf fiber (15% by volume) and TPNR were mixed in as Haake 600p internal mixer. The fracture behavior of the TPNR matrix and of TPNR--kenaf (with and without maleic anhydride grafted polypropylene, MAPP) composites was evaluated using the essential work of fracture (EWF) method and double edge notched tensile (DENT) specimens. Various ligament lengths were employed ranging from 4 to 12mm. The strain rate was fixed at 2 mm/min. The specific work of fracture (we) and plastic work (ßwp) showed the highest energy for TPNR that corresponds to its ductility and allows the application of the EWF approach. It was found that the presence of kenaf fibers and MAPP reduced the toughness of TPNR and changed the ductile fracture to brittle behavior. SEM observation revealed that energy absorption mechanisms include matrix deformation, fiber pullout, and fiber breakage. Acoustic emission (AE) was employed to analyze the failure processes further. The signals emitted by composites were substantially higher than that of the TPNR matrix, reflecting that also the failure mechanisms were affected by the fibers incorporated. [ABSTRACT FROM AUTHOR]