Kenaf Research Articles

Analyzing the influences of fabrication methods on the mechanical properties of Sumberejo kenaf/epoxy sandwich composites with polyurethane foam core

Natural fiber composite sandwich structures have developed significantly to create building materials that are strong and lightweight. The purpose of this study is to compare the cold press and vacuum assisted resin infusion (VARI) methods to investigate the mechanical properties of sandwich composites made of Sumberejo kenaf fiber (KF) reinforced epoxy (EP) as the skin and polyurethane (PU) foam as the core. The kenaf fibers were alkalized by NaOH solution. The results show that manufacturing KF/EP-PU foam sandwich composites using cold press has flatwise tensile strengths that are around (0.220 ± 0.031) MPa higher than VARI, which is only about (0.170 ± 0.057) MPa. This implies that cold press creates an enhanced composite structure. The core shear strength of cold press sample was 17% higher than VARI, with a value of (0.603 ± 0.052) MPa and (0.499 ± 0.016) MPa, respectively. Also, the skin bending stress of cold press sample was (6.106 ± 1.203) MPa while VARI sample had a value of (5.405 ± 0.687) MPa. However, the VARI method exhibited higher flatwise compressive strength with a value (0.393 ± 0.004) MPa and cold press method was (0.331 ± 0.032) MPa. In conclusion, the manufacturing method substantially impacts the mechanical properties of KF/EP-PU foam sandwich composites in this study. This study is a valuable reference for natural fiber sandwich composites as a building material.

Direct and Indirect Tensile Behavior of Cement-Zeolite-amended Sand Reinforced with Kenaf Fiber

Direct and Indirect Tensile Behavior of Cement-Zeolite-amended Sand Reinforced with Kenaf Fiber

Mechanical Behavior of Handmade Epoxy-Based Composites

The development of products in a variety of industries is now being increasingly influenced by material advancements. Many experts are looking for basic materials that are strong, light, and inexpensive. Solids are often rather thick, whereas light materials are weaker. To attain significant strength while lowering weight, we use composite materials. This work deals with the mixed effects of composites made by hand using an epoxy tar and a hardener along with different fiberes of chopped mate (KC), Kenaf (KA), and Kevlar (KB). Mechanical studies such as tensile (UTS), flexural (FL), impact (IM), and hardness (BHN) were conducted after creating specimens according to standard measurements.

Development of the drone frame kit made up of natural fiber

Increased environmental consciousness and demand for sustainable materials have encouraged the use of more renewable and environmentally acceptable resources as reinforcement, for the natural fiber like the (Pineapple Leaf Fiber) PALF and Kenaf fiber material. These materials are natural fiber which are environmental friendly and biodegradable. This environmental friendly resources has been a demand in all industries including the aerospace industry. So, this project is to develop a drone frame kit made up of natural fiber. There are very less studies on the drone frame kit made up of natural fiber. Drones are mostly made up of synthetic fiber which is not biodegradable. Three designs of the drone frame kit had been designed by Fusion 360 software where the best frame kit with least stress distribution, least total deformation and least strain will be chosen to develop the frame. Ansys simulation can be used to analyze the frame kits for the finite element analysis. In the Ansys simulation the static structural part had been chosen to make the analysis where few boundary conditions added, and the mesh dependency test was done to get the best result. PALF and Kenaf had be chosen to be analyzed because those natural fiber having high tensile strength compared to other natural fiber. So as the project is to build a drone, there had been an idea of developing the frame kit natural fiber like the PALF and the Kenaf material. In conclusion, each and every design having their own uniqueness where the best design with least stress was the design with circular shape.

Study on the effect of CuO influenced kenaf fiber reinforced epoxy composite – A novel material for secondary structural applications

This study investigates the effects of copper oxide (CuO) particles on the mechanical and thermal properties of kenaf fibre reinforced epoxy composites, suggesting a new material suitable for structural applications. Comprehensive tests, including Thermogravimetric Investigation (TGA), weakness testing, and Checking Electron Microscopy (SEM), were conducted to evaluate the performance enhancements provided by the incorporation of CuO. The TGA has revealed that CuO particles significantly enhance the thermal stability of the composites. Among the many tests, sample C (6g of CuO) has the highest thermal resistance, retaining 17% of its weight at 500°C, which is higher than the other tests. The fatigue testing demonstrated that the composites exhibited remarkable fatigue resistance, particularly Test C, which maintained a fatigue stress of 14 MPa even after 15,000 cycles, indicating superior durability under cyclic loading circumstances. The SEM study revealed detailed microstructural observations, showing a consistent distribution of CuO particles and strong bonding between the fibres and matrix, which enhance the mechanical performance and resistance to failure.

Remediation of Oil Spills Using Pellets from Waste Papers and Kenaf (Hibiscus cannabinus L) fibres

The clean-up of oil spills from water bodies is a global problem. Enormous quantities of wastes are generated from paper and paper products yearly, which constitutes to serious environmental pollution when disposed inappropriately. Consequently, it is essential to repurpose waste paper in a sustainable manner to address the remediation of oil spills. In this study, absorbent composite pellets of varying waste paper to kenaf fibers compositions were produced for oil remediation and evaluated for their physical (water absorption (WA) and thickness swelling), mechanical (modulus of elasticity (MoE), modulus of rupture (MoR) and impact strength) and remediation capabilities. The WA ranged from 404% to 546% with the highest obtained at 100% paper and the lowest obtained at 20% paper. Mechanical strengths increased with paper composition from 20% (2.19 N/mm2, 0.08 N/mm2, and 0.26 N/mm2) to 100% (6.23 N/mm2, 0.17 N/mm2, and 0.86 N/mm2) for MoE, MoR and Impact strength respectively. The pellets having 20% paper and 80% Kenaf pellet was recorded as optimum for the remediation of oil spills.

Modification on nanocellulose extracted from kenaf (Hibiscus cannabinus) with 3-aminopropyltriethoxysilane for thermal stability in poly (vinyl alcohol) thin film composites

Modification on nanocellulose extracted from kenaf (Hibiscus cannabinus) with 3-aminopropyltriethoxysilane for thermal stability in poly (vinyl alcohol) thin film composites

Compressive and Flexural Strengths of Bio-Recycled Concrete Incorporated with Kenaf Fibre

ABSTRACT Kenaf fiber (KF) has been applied in concrete to compensate for the weak tensile strength. Similarly, recycled concrete aggregate (RCA) is applied to reduce problems associated with waste concrete materials. However, both KF and RCA reduce the compressive strength (fck) of concrete. This study involves addition of calcite-producing bacillus subtilis bacteria to recycled aggregate concrete (RAC) incorporated with KF. The bacteria is added to concrete with varying proportions of RCA and KF to produce bio-fibrous recycled concrete (BFRC). The proportions of RCA are 0%, 25% 50% and 75% replacement of coarse aggregate, while KF are 0.2%, 0.5% and 1% of concrete. W/C of 0.45, 0.5, and 0.6 are applied to evaluate the effects of different w/c ratios. The properties evaluated are the fck and the flexural strength (ft) of the concrete samples at 28 days. The results showed that 0.2% KF in bio-concrete (BC) increases the fck by 12%; however, increasing above 0.2% decreases fck. KF in BC increases ft by 60%. Furthermore, 0.5% KF content resulted in highest ft of BRC. Increasing RCA content in bio-recycled concrete and BFRC decreases fck by 30% and 33%, respectively, as well as ft by 13% and 18%, respectively.

Effect of Maleic Anhydride Polypropylene on Flexural Properties of Hybrid Kenaf - Sugar Palm Fibre Reinforced Polypropylene Composites

This study was focused on the characterize the hibridisation of kenaf and sugar palm fibre in reinforcing the polypropylene matrix. Addition of MAPP (Maleic Anhydride Polypropylene) was used as compatibilizing agent with variation of 2%, 3% and 5%. The specimen materials were prepared with 30% amounts of fibres while the ratios between kenaf and sugar palm fibre are 10:20, 15:15 and 20:10. The composites were fabricated using melt mixer technique and followed by compression molding process. The specimens were cut according ASTM Standard D790 for conducting the flexural testing. After testing done, the results shown that flexural strength of composites tend to decreased when the content of MAPP increased. The ultimate flexural strength was attained at 2% MAPP addition of the hybrid composites with 20% kenaf fibres. Among the composites with different ratios, the hybrid composites that contain more kenaf fibres exhibit the higher value in flexural strength than the composites that contain more sugar palm fibres.

Fractionation and physicochemical characterization of dietary fiber of kenaf (Hibiscus cannabinus L.) seed.

Kenaf seeds are underutilized kenaf plant by-products, containing essential nutrients including dietary fiber (DF), which can be potentially utilized as food ingredients. The present study aimed to evaluate the physicochemical characteristics of kenaf seed fiber fractions extracted from kenaf seed. Defatted kenaf seed powder yielded four DF fractions: alkali-soluble hemicellulose (146.4 g kg-1 ), calcium-bound pectin (10.3 g kg-1 ) and acid-soluble pectin (25.4 g kg-1 ) made up the soluble fibre fraction, whereas cellulose (202.2 g kg-1 ) comprised the insoluble fraction. All fractions were evaluated for their physicochemical properties. The DF fractions contained glucose, mannose, xylose and arabinose, and a small amount of uronic acid (1.2-2.7 g kg-1 ). The isolated pectin fractions had a low degree of esterification (14-30%). All the isolated DF fractions had high average molecular weights ranging from 0.3 to 4.3 × 106 g mol-1 . X-ray diffractogram analysis revealed that the fractions consisted mainly of an amorphous structure with a relative crystallinity ranging from 31.6% to 44.1%. The Fourier-transform infrared spectroscopy spectrum of kenaf seed and its DF fractions showed typical absorption of polysaccharides, with the presence of hydroxyl, carboxyl, acetyl and methyl groups. Scanning electron microscopy analysis demonstrated that the raw material with the rigid structure resulted in soluble and insoluble DF fractions with more fragile and fibrous appearances, respectively. The soluble DF demonstrated greater flowability and compressibility than the insoluble fractions. These findings provide novel information on the DF fractions of kenaf seeds, which could be used as a potential new DF for the food industry. © 2023 Society of Chemical Industry.

Study of impact performance of composite sandwich structure fabricated partially with natural fiber facesheet

AbstractComposite structures with a pure glass composite facesheet and an aluminum honeycomb core are widely used in aircraft interiors. Because impact‐related problems are related to structural integrity and safety performance, the behavior of these structures under impact loading is critical. Due to their promising performance, lower cost, and low environmental impact, hybrid composites have recently become one of the most widely researched composite materials in the research field. This paper aims to investigate the impact behavior of nonhybrid glass and the glass partially replaced with a flax and kenaf hybrid composite facesheet caused by a low‐velocity impact. The specimens were impacted with different impacted energies, such as 10, 20, and 30 J. All nonimpacted and impacted samples were tested and compared for postimpact flexural (three‐point bending) behavior to analyze the residual strength of sandwich structures after impact. The results revealed that the hybrid composite face sheet outperformed the glass composite sandwich structure. The hybrid composite face sheet allowed the impactor to penetrate deeper, resulting in better energy absorption than the glass composite. Compared to nonimpacted specimens, the glass and hybrid face sheet combinations demonstrated comparable residual bending performance.Highlights Experimental analysis shows the impact resistance (low‐velocity impact test) and residual load‐carrying capacity (three‐point bending test) of glass and hybrid composite face sheets. Hybrid face sheets show excellent energy‐absorbing capability compared to glass one. The residual flexural strength of the glass and hybrid composites was comparable to that of nonimpacted samples. The peel strength achieved in this study using the pre‐cure fabrication process was significantly higher than the peel strength achieved using prepreg face sheets. Reinforcing the composite face sheet of the sandwich structure by partially replacing the glass with flax and kenaf fiber exhibited comparable performance.

Investigation Of Stacking Layer Effect on The Kenaf Hybrid Composite Mechanical Properties for Automotive Application

The field of automotive manufacturing continually seeks innovative, sustainable materials with an emphasis on mechanical robustness. The study is aimed at investigating the Kenaf fibers' potential as an alternative to synthetic fiber composites in automotive bumper beams, shedding light on the mechanical properties of this hybrid composite. The primary focus lies on the impact of different fiber orientations: unidirectional, bidirectional, and 45-degree angles. Using the hand layup process, a natural fiber composite served as the material for constructing the sample, tested for mechanical properties with a Universal Testing Machine. Findings from both tensile and flexural tests illuminate the mechanical properties of Kenaf fiber composite, providing valuable insights into its utilization potential. The Kenaf hybrid composite showcased viable mechanical properties, suggesting its potential for automotive applications. The research establishes Kenaf fibers as a promising, sustainable alternative that could revolutionize the automotive industry without compromising structural integrity.

Mechanical separation of kenaf for composite applications – Evaluation of the total fibre line concept for field retted kenaf

This publication introduces a promising concept for the effective decortication and separation of kenaf stems, which is adapted to different degrees of retting. Kenaf (Hibiscus cannabinus L.), a natural fibre with immense potential for sustainable materials, presents challenges in decortication due to its diverse properties. In response, we offer a technical solution that achieves exceptional cleaning efficiency, resulting in fibre-free shives and nearly shive-free fibre bundles. Our investigations reveal that the degree of decortication of kenaf stems can be finely adjusted using different cleaning concepts. The process attains optimal fibre bundle lengths through cleaning steps, rendering them ideal for fleeces and needle felts in the automotive industry. Furthermore, our separation pre-tests demonstrate the suitability of the total fibre line concept for kenaf processing. Particularly, well-retted kenaf showcases superior processability compared to non-retted kenaf. The significance of this study lies in developing an efficient and sustainable solution for harnessing kenaf’s potential as an automotive material. By optimising the decortication process, we can obtain high-quality fibres that meet the demands of automotive applications, contributing to creating eco-friendly and lightweight materials. As sustainability gains prominence in industries worldwide, the total fibre line concept presents a crucial step forward in realising greener and more environmentally conscious automotive practices. The abundance and renewability of kenaf, combined with the cost-effectiveness of our proposed decortication approach, make it a viable alternative to traditional materials derived from fossil fuels. This research establishes the feasibility and benefits of adopting our total fibre line concept for processing kenaf stems. The versatility of this technology offers opportunities for further exploration and extension to other natural fibres to promote a more sustainable future for the automotive industry and beyond.

Influence of Nitrogen Supply on Growth, Antioxidant Capacity and Cadmium Absorption of Kenaf (Hibiscus cannabinus L.) Seedlings

Kenaf (Hibiscus cannabinus L.) is considered suitable for the remediation of cadmium (Cd)-contaminated farmlands, because of its large biomass and resistance to Cd stress. The addition of nitrogen (N) fertilizer is an important measure used to increase crop yields, and it may also affect Cd accumulation in plants. To clarify the effects of different forms and concentrations of N on plant growth and Cd absorption in kenaf, a hydroponic experiment was conducted using three N forms (NH4+–N, NO3−–N and urea–N) at four concentrations (0, 2, 4 and 8 mM, 0 mM as control) under Cd stress (30 μM). The plant growth, the antioxidant enzyme activity and the Cd contents of various parts of the kenaf seedlings were measured. The results showed that the N form had the greatest impact on the growth of the kenaf and the absorption and transport of the Cd, followed by the interaction effect between the N type and the concentration. Compared to the control, the addition of N fertilizer promoted the growth of kenaf to varying degrees. Among all the treatments, the use of 2 mM of NO3−–N enhanced the biomass and Cd accumulation to the greatest extent compared to CK from 2.02 g to 4.35 g and 341.30 μg to 809.22 μg per plant, respectively. The NH4+–N significantly reduced the Cd contents of different parts but enhanced the translocation factors of Cd stem to root (TF S/R) and leaf to stem (TF L/S) by 34.29~78.57% and 45.10~72.55%, respectively. The peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) enzyme activities of the kenaf increased with the N treatments, especially with NH4+–N. Overall, applying low concentrations of NO3−–N can better promote the extraction of Cd by kenaf.

Central composite design for optimization of kenaf-reinforced epoxy composite bonding performance

Kenaf fiber is gaining prominence because of its ability as a natural-based reinforced material in advanced composites. However, kenaf contains a hygroscopic natural waxy substance that covers the fiber layer, providing a low surface tension and preventing strong bonding with the polymer matrix. The goal of this study is to optimize the blending parameters of kenaf fiber-reinforced epoxy composites by alkali treatment concentration, length, and fiber-matrix loading using central composite design. The maximum tensile strength was obtained at 6.03 wt% of NaOH concentration, fiber loading of 26.02 wt%, and fiber length at 7.39 mm, which showed a strong correlation between experimental and predicted values. The analysis of variance function model indicated that fiber length, sodium hydroxide concentration, and fiber loading all play important roles in mechanical properties of composites. Based on the fracture surface observations, kenaf fiber composite strength was closely related to bonding at fiber-matrix interfaces. The most common failure modes in the samples were voids, matrix fracture, fiber breakage, weak bonding, and fiber pull-out.

Green synthesis of Kenaf-based activated carbons with excellent rate capability and cycle-life via hydrothermal-co-activation process for high-performance capacitive energy storage

The invention of high-performance electrode materials through a simple and green approach is always important for energy storage applications. Herein, we have prepared highly porous activated carbons (ACs) from biomass kenaf (KF) by hydrothermal and steam activation methods. A number of optimization experiments, such as hydrothermal pre-treatment (100, 150 and 200 °C), steam activation temperature (600, 700, 800, and 900 °C) and time of steam flow (15, 30, 60 and 90 min) were performed to control the specific surface area, micro- and/or meso-pores, total pore volume for an excellent electrochemical performance. The as-obtained porous ACs exhibited a high specific surface area (∼1733 m2/g) with high total pore volume (∼0.916 cm3/g) and high mesopore volume (∼28.4%), which are beneficial for the excellent double layer formation over the surface of activated electrode and also provide transport channel for an effective diffusion of electrolyte ions. The as-derived ACs were used as electrode materials for the fabrication of symmetric supercapacitor device in 6 M KOH. The fabricated device exhibited a high energy density of 4.86 Wh kg−1 at power density of 2500 W kg−1 with outstanding stability (∼96.3%) over 10,000 charge-discharge cycles.

Effect of non-acidic chemical treatment of kenaf fiber on biodegradation and thermal degradation of kenaf/PLA green composite laminates

Effect of non-acidic chemical treatment of kenaf fiber on biodegradation and thermal degradation of kenaf/PLA green composite laminates

Mechanical property enhancement of graphene-kenaf-epoxy multiphase composites for automotive applications

Kenaf composites have a high strength-to-weight ratio, but weak fiber–matrix interface bonding limits their automotive use. To address this, a novel technique was developed to fabricate multiphase composites using graphene nanoplatelets (GNPs), kenaf fibers, and an epoxy matrix. The composites were made using vacuum infusion molding, with the GNPs exfoliated using a bath sonicator for uniform dispersion. The composites modified with 0.2 wt% GNP showed the most significant improvement in mechanical properties. Specifically, these composites exhibited a 30.5% increase in tensile strength, a 61.5% increase in tensile modulus, a 17.6% increase in flexural strength, a 22.7% increase in flexural modulus, a 35.1% increase in interlaminar shear strength, and a 17.1% increase in fracture toughness. Additionally, the water absorption resistance of the multiphase composites improved by up to 7%. These improvements were attributed to the uniform dispersion of GNPs and improved interlocking with the fiber surface. The developed composite has the potential for interior parts (such as dashboards, interior walls, and luggage compartments) in the automotive vehicle.

A simple rheological method for the experimental assessment of the fiber percolation threshold in short fiber biocomposites

The identification of the percolation threshold (Φc) in short fiber composites is a challenging problem in Composite Science. Above Φc the fibers form a continuous network that causes substantial changes in mechanical and transport properties. Besides, percolation of natural fibers in biodegradable polymer matrices allows water and other pro-degradative species to access the inner parts of the material from the external environment, accelerating biodegradation. Whether such a speeding up is desired or not, assessing Φc in composites is of utmost importance. Unfortunately, natural fibers are not conductive and exhibit highly variable shape and physical properties. This prevents the use of many experimental and theoretical approaches for the estimate of Φc. Here we propose an original rheological approach borrowed from the viscoelastic modelling of polymer nanocomposites. The method was applied to two systems made of poly(lactic acid) filled with hemp or kenaf fibers (average length <500 μm, average length-to-diameter ratio <5). The estimate of Φc (∼10.1 and 19.5 vol% for the hemp- and kenaf-based composite, respectively) required a single set of simple linear viscoelastic measurements, and the computed values were in good agreement with those obtained through time-consuming (measurement times >3 weeks) dielectric spectroscopy analyses (∼10.1 and 18.5 vol%).

Tartaric acid coupled with gibberellin improves remediation efficiency and ensures safe production of crops: A new strategy for phytoremediation

Phytoremediation is the direct use of living green plants and it is an effective, inexpensive, non-invasive, and environmentally friendly technique used to transfer or stabilize all the toxic metals and environmental pollutants in polluted soil or ground water. To study the effect of tartaric acid, gibberellin, and tartaric acid coupled with gibberellin on rape-kenaf or rape-sweet sorghum rotation, a field experiment was carried out on a farmland combined polluted with Cd and Pb in eastern Hunan Province, China. The results showed that these two rotation systems coupled with superposition measure has potential to enhance yield and biomass of rape (Brassica napus L.), kenaf (Hibiscus cannabinus) and sweet sorghum (Sorghum dochna (F.) Snowden), as well as to increase Cd and Pb uptake of the three crops, thus accelerating phytoextraction. The Cd and Pb annual removal by rape-kenaf rotation in one year under different treatments were 269–438 and 112–149 g·hm−2, respectively. And the Cd and Pb annual removal by rape-sweet sorghum rotation in one year under different treatments were 68.0–111 and 43.8–92.3 g·hm−2, respectively. Under the two rotation systems, these integrated management measures can remove Cd and Pb up to 438 g·hm−2·year−1 and 149 g·hm−2·year−1, respectively. The Cd and Pb content in rape seeds or sweet sorghum stems and leaves were lower than the food or forage standard, indicating that we can use this rotation system for both remediation and safety production. Furthermore, the two rotation systems also generated considerable economic value. These results showed that the combination of phytoremediation and agricultural production is a feasible technical mode in the field of Cd and Pb co-contamination, and also provides useful information for further study of the interaction mechanism between rotation crops and enhancement measures. In subsequent experiments we can set concentration gradients for tartaric acid and gibberellin, and we can also select other crops for rotation, with a view to finding the optimal auxiliary measure and crop rotation modern.