Mechanical performance and morphological behaviour of hybrid kenaf and empty fruit bunch fibres reinforced poly(lactic acid) biocomposites

In this study, the drilling performance of kenaf fiber reinforced plastic (KFRP) composites with fiber orientations of 0°/90°, 30°/−60°, and ±45° was experimentally investigated. The composites were manufactured using the vacuum infusion method and mechanically characterized through tensile tests to support the interpretation of machining behaviour. Drilling experiments were carried out under different spindle speeds and feed rates to evaluate their effects on cutting force, temperature, and delamination factor. The results showed that the 0°/90° fiber orientation exhibited the highest tensile strength, while the ±45° configuration showed the lowest, reflecting the influence of fiber alignment on load-bearing capability. During drilling, cutting forces decreased with increasing spindle speed and increased significantly with feed rate, with feed rate identified as the dominant parameter. The 30°/−60° orientation resulted in the lowest thrust force and temperature values, whereas the ±45° orientation exhibited the highest thermal and mechanical responses, which corresponded to higher delamination factor. Statistical evaluation using analysis of variance (ANOVA) confirmed the significant effects of fiber orientation, spindle speed, and feed rate on cutting force, temperature and delamination factor.

The drive towards sustainable, lightweight building materials has accelerated interest in natural fibre-reinforced composites, yet challenges in strength performance remain a major limitation. This study investigates the influence of alkali treatment duration on the reinforcing efficiency of Treated Kenaf Fibre (TKF) in Lightweight Foamed Composites (LFCs) with a target density of 1200 ± 50 kg/m³. The experimental programme optimised the water-to-cement (W/C) ratio, characterised fibre surface modification using Scanning Electron Microscopy (SEM) and Energy-dispersive X-Ray spectroscopy (EDX), and evaluated fresh and mechanical properties, including compressive, residual, splitting tensile and flexural strengths. An optimum W/C ratio of 0.60 provided adequate workability without compromising strength development. SEM and EDX analyses indicated progressive fibre surface modification with increasing treatment duration, with the 12-h TKF exhibiting the most pronounced surface contaminants removal and surface roughness. Proceed to composite incorporation, LFC-TKF-12H showed slightly reduced flowability while maintaining improved density consistency and mix stability. Additionally, LFC-TKF-12H exhibited the highest overall mechanical performance among all mixes. Relative to the control mix, the compressive strength increased by 19%, splitting tensile strength by 38%, flexural strength by 34% and residual strength by 36%, corresponding to a strength retention factor of 76%. The results highlight alkali treatment duration as a key parameter governing fibre surface modification and reinforcing effectiveness in LFCs.

Agricultural residues and agro-waste are increasingly recognized as valuable reinforcements for sustainable composite materials. Natural fibers derived from these biomasses offer biodegradability, low density, renewability, and potential environmental benefits. However, their performance and sustainability depend strongly on extraction, surface treatment, and processing conditions. Therefore, evaluating the environmental emissions associated with natural fiber biocomposites is essential before claiming sustainability advantages. In this research, flax, jute, kenaf, and bagasse fibers were extracted and treated using an eco-friendly sodium bicarbonate solution, then incorporated into polylactic acid (PLA) matrix to fabricate biocomposites via injection molding. A life cycle assessment (LCA) was conducted using the ReCiPe midpoint (H) method, with a functional unit defined as “per kg” of manufactured biocomposite. The results revealed that jute fiber composites generated the highest emissions across several impact categories, including climate change (1.290 × 101 kg CO2-Eq), terrestrial ecotoxicity (6.327 × 101 kg 1,4-DCB-Eq), human toxicity: carcinogenic effects (1.923 kg 1,4-DCB-Eq), and fossil resource use (3.202 kg oil-Eq). Jute also showed a 3.6% increase in terrestrial ecotoxicity and a 19.5% increase in land compared to flax, although it exhibited a 6.5% lower impact related to bagasse. A ±20% electricity-consumption sensitivity analysis further highlighted the dependence of environmental impacts on processing energy demand.

Fused filament fabrication (FFF) is a printing technology that relies on remelting and modelling physical objects from thermoplastic filament materials. Natural fibres have been studied and used for polymeric reinforcement. Yet, there is limited information in the literature about reinforcing filament materials for FFF printing. This study aimed to evaluate some surface properties of FFF 3D printed polyamide 6 reinforced with kenaf fibres. Kenaf fibres were retted, bleached with sodium hypochlorite solution, and silanised with 3-aminopropyltriethoxysilane solution prior to thermally compounding with polyamide beads to produce filaments for experimental groups. A total of 55 specimens were printed by an FFF printer for 5 groups: control, 0.1%, 0.3%, 0.5% and 1% kenaf fibres-reinforced polyamide (11 specimens for each group). Fourier-transform infrared spectroscopy analysis was conducted on the control and 1% kenaf-reinforced sample for chemical characterisation. The study groups were submitted to surface roughness, surface hardness and water contact angle measurement tests. The results showed no significant chemical change in the composite as a result of fibre incorporation. Surface hardness have shown a significant increase in their mean values after fibres incorporation, which were 93.3, 93.5, 92.2, 91.3 for 0.1, 0.3, 0.5 and 1% respectively compared with the control 88.9, while there was no significant difference in both surface roughness and surface hydrophilicity except for 1% kenaf-reinforced group (roughness = 358, contact angle = 55.1) compared to the control group (roughness = 216, contact angle = 46.4). Kenaf fibres reinforcement with polyamide 6 at concentrations not more than 0.5% has improved the surface hardness of the FFF printed material.

This article aims at investigating the mechanical properties of kenaf fibres epoxy biocomposites with various fibre volume contents. Ukam plant (kenaf) fibres are natural fibers which have many advantages capable of making them suitable reinforcement for composite development. In this article, density tests were carried out on kenaf fibers and epoxy resin while tensile tests were carried out on kenaf fiber polymer composites. Six samples ranging from 0% to 50% fiber volume fractions were tested. From the results, the liquid density of epoxy resin is 1.10g/cm3 and cured density of epoxy resin is 1.03g/cm3. The ultimate strength obtained from the stress against strain graphs were between 14.00MPa and 88.8MPa while the highest value of Young's Modulus at 50% fiber volume fraction is 10.67GPa. This shows that mechanical properties of fibre reinforced composites increase with increase in fibre volume fractions.

Establishment of an Agrobacterium-mediated CRISPR/Cas9 Genome Editing System for Kenaf (Hibiscus cannabinus).

ABSTRACT The expanding kombucha market drives demand for diverse functional products. This study explored underexplored commodity crop byproducts, including Melicope pteleifolia leaves, oil palm ( Elaeis guineensis ) leaves, mango ( Mangifera indica ) leaves, kenaf ( Hibiscus cannabinus ) leaves, coffee ( Coffea spp.) leaves, and cocoa ( Theobroma cacao ) rind as alternative sustainable fermentation substrates. The aim was to optimize fermentation conditions and comprehensively evaluate the physicochemical, nutritional, antioxidant, and sensory properties of these kombuchas. Utilizing a single factor experimental design approach, fermentation was optimized for sugar concentration, temperature, and residue presence, with analyses covering key quality attributes including pH, ethanol, total phenolic content (TPC), total flavonoid content (TFC), DPPH free radical scavenging activity, and sensory properties. Optimal conditions were 37°C, 5% (w/v) sugar, and fermentation without residues for 6–8 days. All optimized kombuchas exhibited safe pH and low ethanol profile. Coffee leaves kombucha yielded the highest TPC, while mango leaves kombucha had the highest TFC. Melicope pteleifolia kombucha showed superior antioxidant activity (DPPH IC 50 529.2 mg/mL) and achieved the best overall consumer acceptability (5.8/7). This research successfully developed novel, safe, and functional kombucha beverages. Melicope pteleifolia kombucha holds particular promise as a functional drink, offering a valuable alternative and valorizing plant resources. Future pilot‐scale studies are essential for commercialization.

Deccan hemp protein-based hydrogel formation through glucono-δ-lactone mediated aggregation and enzymatic crosslinking: characterizations and in vitro release.

Effect of water absorption on the behaviour of jute/kenaf fiber at various lengths by ANN and RSM modelling

Prolonged exposure to adverse conditions affects the performance and promotes the degradation of reinforced concrete (RC) structures, requiring repair and strengthening to preserve their integrity and functionality. Synthetic fibers, including carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP), are frequently employed for retrofitting owing to their superior strength-to-weight ratio and simple installation. Natural fibers, such as kenaf, have been increasingly incorporated into fiber reinforced polymer (FRP) composites as sustainable alternatives in the construction industry due to their lightweight nature and low carbon footprint. Yet, many investigations focused on synthetic fibers, thus, the purpose of this study is to develop finite element (FE) models for RC beams and columns retrofitted with CFRP, GFRP and kenaf fiber reinforced polymer (KFRP), to examine the impact of natural fibers and comparing the findings with those derived from synthetic fibers. The models consider element types, mesh discretization, solution methodologies, and nonlinearities. Concrete behavior is represented using Concrete Damage Plasticity (CDP), whereas fiber laminates employ the Hashin damage model. The FE model's load-displacement behavior, ultimate strength, and failure mechanisms were verified against existing experimental and numerical findings. The findings indicate that FRP wrapping substantially enhances the load-carrying capacity of RC beams, with ultimate load increases ranging from approximately 13% for KFRP to 66% for CFRP, whereas the corresponding improvements for RC columns are notably smaller, remaining below 7%. Although KFRP exhibits lower mechanical performance than GFRP and CFRP, its sustainability and cost-effectiveness support its use in applications where environmental and economic considerations are prioritized.

Abstract The effect of grafting maleic anhydride (MAH) on the physical and mechanical properties of PBAT-g-MAH/Kenaf fiber composites is investigated. PBAT, a biodegradable polymer with excellent ductility, shows limited stiffness and high cost, restricting its industrial applications. To overcome this, MAH is grafted onto PBAT using dicumyl peroxide (DCP) as an initiator through a reactive melt-processing method. The introduction of MAH significantly enhances the interfacial adhesion between PBAT and Kenaf fiber, enabling effective stress transfer and uniform fiber dispersion within the composite. The optimized grafting condition is determined to be 0.3 phr DCP and 3 phr MAH. Furthermore, the incorporation of 4 wt% Kenaf fiber achieves a balance between mechanical reinforcement and rheological stability. Morphological analysis and property evaluation confirm that the grafting of MAH effectively improves the compatibility and mechanical performance of PBAT-based composites, offering potential for expanded application in eco-friendly packaging materials. Graphical abstract This study demonstrates the effect of maleic anhydride (MAH) grafting on the interfacial compatibility and mechanical properties of PBAT/Kenaf fiber composites. MAH improves adhesion and dispersion between PBAT and Kenaf fiber, resulting in enhanced stiffness and balanced mechanical performance. The optimized composition shows great potential for sustainable packaging and industrial applications.

ABSTRACT This study analyzes the effect of MgO, Al 2 O 3 , and TiO 2 metal oxide fillers on the physico‐mechanical and thermal behavior of kenaf/carbon fiber‐reinforced epoxy hybrid composites. Pb 3 O 4 ‐treated kenaf fibers were combined with carbon fiber mats to create a kenaf–carbon–kenaf (KCK) layered system, fabricated using the hand lay‐up method. Metal oxide fillers were added at concentrations of 1% and 2% to examine their effects on mechanical and physical properties. The tensile test results revealed that the 2% MgO delivered the highest strength of 93.74 MPa, surpassing the control sample (91.3 MPa) and also outperforming the Al 2 O 3 and TiO 2 incorporated sample. Flexural strength reached the maximum of 128.28 MPa with 2% of MgO, which is 41.98% higher than that of the control sample (90.35 MPa). The maximum impact strength was obtained at 2% Al 2 O 3 at 56.4 KJ/m 2 , a 37.46% increase from the control sample (41.03 KJ/m 2 ). In terms of moisture resistance, 2% TiO 2 demonstrated the best performance, showing the lowest water absorption. Additionally, the inclusion of metal oxide fillers improved the thermal properties. The higher diffusivity of 2% TiO 2 (0.198 mm 2 /s) and MgO (0.191 mm 2 /s) with lower volumetric specific heat (1.24 MJ/m 3 ·K) indicates rapid heat transfer, whereas the lower diffusivity of Al 2 O 3 (0.147 mm 2 /s) and the control (0.116 mm 2 /s) with higher volume specific heat favors insulation performance. Al 2 O 3 at 2% provides high thermal conductivity while maintaining moderate heat retention. Morphological analysis revealed that 2 wt.% MgO incorporated samples had good fiber‐matrix adhesion, but increased Al 2 O 3 and TiO 2 loadings had voids and agglomeration.

Reinforced Sweet Potato Starch Bioplastics with Kenaf Fiber and Indian Jujube Extract

Abstract The search for sustainable alternatives to peat-based substrates in horticulture has intensified due to environmental concerns, rising costs, and limitations of peat resources. Consequently, there is a continued need for alternative media. This study evaluated composted kenaf ( Hibiscus cannabinus ) growing media, formulated with food and landscape waste (Mix A: 40% kenaf, Mix B: 30% kenaf), as substitutes for commercial Promix BX in the production of coleus ( Solenostemon scutellarioides ‘Wasabi’). Cuttings were grown in 25%–100% composted kenaf-based media for five weeks. Growth parameters, shoot and root biomass, media pH, electrical conductivity (EC), and nutrient composition were measured. Composted kenaf-based media supported coleus growth equal to or greater than the control, especially with higher proportions of Mix B, linked to elevated nitrogen and potassium. Although pH and EC were initially higher in kenaf-based mixes compared to Promix BX, both levels decreased over time and did not impair plant growth or quality. Despite lower phosphorus and some micronutrient concentrations compared to Promix BX, these findings suggest that composted kenaf-based substrates can serve as a promising, sustainable alternative to peat-based media for ornamental plant cultivation, provided that nutrient balance and pH are further optimized. Species used in this study: Kenaf ( Hibiscus cannabinus L .), Coleus [ Solenostemon scutellarioides (L. ) Codd].

Performance enhancement of hybrid kenaf/bamboo fibre-reinforced bio-epoxy composites for sustainable structural applications

Although natural and recycled fibre-based insulation materials show promising thermal and acoustic performance, several challenges still limit their widespread adoption. This paper explores the properties and potential of recycled textile and natural fiber-based materials in enhancing building renovations. Specifically, it examines two types of insulation panels: those made from recycled textiles (Panels M) and those composed of kenaf and hemp fibers (Panels K). The study investigates various properties, including composition, density, thermal conductivity, acoustic performance, and fire response, highlighting the strengths and challenges associated with each material. The results reveal that while textile-based panels exhibit more variability in composition and performance, natural fiber panels are more uniform, making them a more predictable and reliable option. Thermal conductivity values ranged from 0.035 to 0.049 W/(m·K), with the natural fiber panels showing more consistent results. Acoustic performance, evaluated using both Sonocat sensor and the impedance tube also varied, with textile-based panel M45 performing particularly well approaching the Basotect performance (this latter used as a functional benchmark). Fire response, tested using Temperature Programmed Oxidation (TPO), indicated that kenaf-based panels demonstrated higher flammability compared to their textile counterparts. Furthermore, the study explored the effectiveness of fire retardants, finding that certain treatments helped suppress ignition.

Cyclic nucleotide-gated channels (CNGCs) are evolutionarily conserved calcium-permeable non-selective cation channels that play critical regulatory roles in plant abiotic stress responses. This study characterizes HcCNGC11 in kenaf (Hibiscus cannabinus L.) through integrated genomic and functional analyses. Subcellular localization analysis using GFP-fusion constructs confirmed plasma membrane-specific targeting of HcCNGC11. Tissue-specific expression profiling revealed that HcCNGC11 transcripts accumulate predominantly in roots (2.8-fold higher than leaves), followed by leaves, stems, flowers, and seeds. Notably, HcCNGC11 demonstrated rapid transcriptional upregulation under 150 mM NaCl stress, reaching maximum induction at 3h post-treatment. Virus-induced gene silencing of HcCNGC11 significantly inhibited kenaf growth under salt stress. Biochemical analyses of the silenced lines showed 5-66% reduced activities of antioxidant enzymes (SOD, POD, CAT), decreased osmoregulatory substances (soluble protein, proline), reduced chlorophyll content, and elevated ROS (H₂O₂, O₂·⁻) accumulation. Under salt stress, HcCNGC11-silenced plants displayed significant downregulation of antioxidant enzyme genes (HcSOD, HcPOD, HcCAT) as well as stress-responsive genes (HcP5CS, HcLTP, HcNCED). Conversely, Arabidopsis lines overexpressing HcCNGC11 exhibited 20-47% higher antioxidant enzyme activities, increased osmoregulatory substances, enhanced chlorophyll content, and markedly reduced ROS accumulation compared to WT under salt stress. Molecular analysis of these transgenic lines showed upregulated expression of antioxidant genes (AtSOD1, AtPOD1, AtCAT1) and stress-responsive genes (AtSOS1, AtNHX1, AtCOR15). Protein-protein interaction studies, employing both yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays, identified multiple HcCNGC11 binding partners, including HcCaM7, HcCNGC21, HcTHI1, and HcTCP14. Collectively, these results demonstrate that HcCNGC11 positively regulates plant salt tolerance through modulation of antioxidant systems and stress-responsive pathways.

Abstract Research on natural materials as alternative sound absorbers for buildings continues. This paper presents a natural sound absorber composed of multi-layer coir and kenaf fibers. Normal and random incidence sound absorption measurements were conducted to evaluate the sound absorption performance. The results indicate that adding a thin kenaf fiber layer significantly enhances the sound absorption of the coir fiber. This improvement is observed in the low to mid-frequency range when the kenaf layer, with a smaller thickness than the coir fiber layer, is positioned at the outermost layer. If the kenaf layer is adjacent to a rigid surface, the improvement is predominantly in the mid to high-frequency range. However, if the thickness of the kenaf layer exceeds that of the coir layer, the experiment and Miki’s model demonstrate that the sound absorption coefficient remains nearly identical at mid to high frequency regardless of the arrangement of the layers.

Kenaf (Hibiscus cannabinus) core, an abundant renewable byproduct rich in cellulose and hemicellulose, has emerged as a candidate to replace or supplement peat and coco coir in soilless culture. This review synthesizes the physical, chemical, and biological performance of ground kenaf core and benchmarks it against conventional substrates. Kenaf core exhibits low bulk density (0.06 to 0.15 g cm-3), high total porosity (approximately 90%), and substantial plant available water (approximately 42%), supporting root aeration and water supply. Its pH (6.0-7.2) is near optimal for most crops, whereas electrical conductivity (EC) (3.2-4.7 dS m-1) can exceed recommended ranges for salt-sensitive species, which necessitates pre-leaching or blending. Growth studies show comparable shoot and root performance in blends containing 20 to 70% kenaf, with composted kenaf often outperforming raw core. Pure kenaf generally requires more frequent irrigation and may shrink at high proportions. We outline processing variables such as core purity, particle size, composting, and leaching that govern stability and plant response, identify critical data gaps (including standardized EC and pH methods, and long-term shrinkage), and frame a sustainability agenda. Practically, studies to date indicate that pre-leached kenaf core, incorporated at up to about 70% by volume into peat or coir-based blends with structurally stable components such as perlite, can maintain growth and quality for several ornamental and bedding crops under greenhouse and nursery conditions. At the same time, reports of poor performance in some conifers and early suppression in direct-sown vegetables underscore that the suitability of kenaf-based substrates remains crop specific and dependent on material processing and management.