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This research investigates the effect of kenaf/carbon fiber reinforcement with the addition of nanofillers such as multi-walled carbon nanotubes (MWCNT) and cellulose nanocrystal (CNC) in the phenolic matrix composite. Three different types of samples were made using short carbon fiber, kenaf fiber (KF), BaSO4, Cashew dust, MWCNT, and CNC. Sample 1 contains 40 wt% of carbon fiber with binders reinforced in the phenolic matrix, whereas, in sample 2, carbon fiber has been replaced with KF in the MWCNT-modified phenolic matrix. On the other hand, in sample 3, carbon fiber has been replaced with KF in a CNC-modified phenolic matrix. The physical, mechanical, and tribological properties were investigated and compared. The results showed that sample 1 exhibited higher mechanical performance compared to other samples. On the other hand, the least wear loss and a high coefficient of friction were observed for Sample 2 compared to Samples 1 and 3. Even though KF-based composites exhibited slightly lower mechanical performance, they showed excellent tribological behavior.

Natural fiber reinforced polymeric composites perform poor in mechanical and thermal properties at elevated temperatures due to the cellulose and hemicellulose contents of natural fiber start degrading at elevated temperature. In this research work, flame retardancy and thermal stability of treated and untreated kenaf fiber reinforced epoxy composites have been experimentally investigated and reported. Two composite laminates, one with 6 % NaOH Alkali treated and another with untreated woven kenaf mats, were fabricated by hand lay-up technique followed by compression molding with 40 % fiber weight fractions. Flame retardancy test and various thermal characteristics studies such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), heat deflection temperature (HDT), and morphological analysis via scanning electron microscopy (SEM) tests were carried out. The results showed that alkali treated kenaf fiber composite achieved V0 fire retardancy grade. The major weight losses, 86 % and 75.5 % for untreated and treated composites respectively were recorded between 300 °C and 450 °C. 13.6 % increase in HDT was noted for treated composite with 0.25 mm deflection at 0.45 MPa pressure condition. Thus the composite laminate with 6 % NaOH alkali-treated kenaf fiber achieved the best thermal stability with less degradation which is more suitable for automobile and aerospace applications. [ABSTRACT FROM AUTHOR]

Limitation in practical applications of biopolymer–fiber composite is mainly at higher temperatures. Thus, this study highlights the effects of fiber orientation on the durability of polylactic acid (PLA) reinforced with unidirectional (UD) continuous kenaf fibers at elevated temperatures. PLA and long kenaf fiber were fabricated using the hot-pressing method and stacked at fiber orientations of 0°, 45°, or 90°, relative to the tensile force. Dynamic mechanical analysis of the composites shows excellent anti-shock and temperature-resistant properties of the composite. UD PLA–kenaf composites with a 0° fiber orientation showed an ultimate tensile of ∼190 MPa and a flexural strength of ∼235 MPa, and the strength of the composite was able to retain up to 120°C temperature. The debonding behavior of the fiber from the matrix (fiber pull-out) supported by microscopy proved that interfacial failure occurs from the local strains, which initiate cracking. Interfacial failure and stress transfer have caused a remarkable reduction in composite strength when fibers were oriented at 90°. Hence, this current improvement in the performance of the UD PLA–kenaf fiber composite may potentially replace conventional synthetic fibers, especially for structural automotive applications. [ABSTRACT FROM AUTHOR]

Recent research progresses on tissue culture (e.g. fast reproduction, another culture, protoplast culture and organogenesis) and genetic transformation of kenaf were reviewed and summarized in this paper. Existing problems were discussed, aiming to provide scientific references for promoting tissue culture and genetic transformation of kenaf.

Exfoliated graphite nanoplatelet (GNP) polypropylene (PP)/kenaf fiber (KF) hybrid nanocomposites (PP/KF/MAPP/GNP collectively presented as PKMG) were developed through melt extrusion using a co-rotating screw speed extruder. The loadings of GNPs in nanocomposites were varied from 1-5 phr and characterized for thermal conductivity, stability and behavior, morphology, and heat deflection temperature (HDT). Results revealed increasing effective thermal conductivity with increasing inclusion of GNP. This behavior was attributed to the formation of thermally conductive, interconnected, sheets of GNP which enhanced heat dissipation. Thermal stability analysis revealed high thermal residue content at 3 phr loading attributed to uniform dispersion of GNP sheets in polymer matrix and the formation of enhanced oxygen-barrier due to effective char formation. Results also revealed enhanced HDT (0.46 MPa/1.8 MPa) with increasing incorporation of GNP ascribed to high modulus and thermal stability of GNP sheets. This implies capability of material to sustain loading at high temperatures without losing its rigidity. Thermal behavior revealed increased crystallization temperature and reduced degree of crystallization with slight increase in melting temperature in the range of 2-5°C. Morphological analysis using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) revealed exfoliated and uniform dispersion of graphene in matrix polymer at 3 phr loading. [ABSTRACT FROM AUTHOR]

This work was aimed at applying vacuum-assisted resin transfer molding (VARTM) technique to reinforced polymer molding products made of vegetable fibers. Kenaf ( Hibiscus cannabinus L. Malvaceae) bast fibers were preformed into mat by means of a cold press. The unsaturated polyester resin was infused into the preforms at a vacuum pressure of 1.3-1.6 kPa. The examination of the mechanical properties and microstructure of the prepared composites indicated that the modulus of elasticity (MOE), modulus of rapture (MOR), and tensile strength (TS) of the VARTM composites were increased by 65.5%, 30.7%, and 41.7%, respectively, compared to the traditional hot-pressing composites. The dynamic mechanical analysis (DMA) revealed that the VARTM composite moduli in the temperature range of -50°C-200°C were doubled. The observations by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and mercury porosimetry confirmed that the interfacial compatibility between the kenaf fibers and the polyester resin was substantially improved. [ABSTRACT FROM AUTHOR]