Kenaf Research Articles

Mechanical, water absorption and thermal properties of kenaf fiber composite hybridized with Acacia concinna pods powder

Mechanical, water absorption and thermal properties of kenaf fiber composite hybridized with <i>Acacia concinna</i> pods powder

Full factorial design of the effects of coagulants and processing variables on the physicochemical quality and texture profile analysis of kenaf seed tofu

Aim: Kenaf (Hibiscus cannabinus) is an herbaceous plant of economic significance, the seed is rich in essential nutrients and has the potential for the production of protein-based products. This study investigated the holistic effects of coagulants, kenaf seed-to-water ratio for extraction, and temperature of addition of coagulant on the physicochemical and texture quality of kenaf seed tofu. Methods: Randomised full factorial design was used to obtain different formulations of kenaf seed tofu production under 4 factors at different levels. Results: The main factors of coagulant types, seed-to-water ratio and temperature of addition of coagulant significantly affected the yield, pH, crude protein, crude fat, lightness, yellowness and cohesiveness of the kenaf seed tofu while the redness of the tofu was significantly affected by the coagulant types only. However, the hardness, chewiness and springiness of the tofu were affected by coagulant types and concentrations. Additionally, the 2-way interactions significantly affected the texture profile of the tofu. Though, the 3-way and 4-way interactions have no significant effect on the texture characteristics of the kenaf seed tofu. Conclusions: The tofu made with aluminium potassium salt at concentrations of 0.50 g/100 mL and 1.00 g/100 mL, and 80°C temperature of addition of coagulant formed the highest yield of 71.22 g/100 g and 77.57 g/100 g, respectively. This study also found that aluminium potassium salt and glucono-delta-lactone, with the use of 1:3 seed-to-water ratio and 70°C or 80°C temperature of addition of coagulant were better in terms of hardness and chewiness.

Accumulation and Translocation of Heavy Metals in Hibiscus cannabinus Grown in Tannery Sludge Amended Soil

Digested sludge wasted by tanneries is rich in nutrients and trace elements however, the presence of toxic metals restricts their use in agriculture. The present study explores the possible application of tannery sludge amendment for the cultivation of an energy crop, Hibiscus cannabinus. The toxicity of various sludge amendments (25, 50, 75, and 100%, w/w) was examined during early seedling growth, followed by metal accumulation potential by performing pot experiments. Chemical characterization revealed the presence of Cr (709.6), Cu (366.43), Ni (74.6), Cd (132.71), Pb (454.8) μg.g-1 in tannery sludge beside N (2.1%), P 3.8 &amp; K 316.96 (kg.hec-1.) respectively. Germination of H. cannabinus exposed to sludge extracts ranged between 80 to 95%; Relative seed germination, 81.33 to 84.43%. Relative root growth, 0.9 to 1.16 cm; and germination index, 95 to 110%. It was found that sludge extracts have not caused adverse effects on seed germination and early seedling growth. Heavy metal accumulation was observed as follows: Ni (3.37, 2.38, 1.46 &amp; 0.90 mg.kg-1) &gt; Pb (10.59, 10.15, 5.26, &amp; 2.84 mg.kg-1) &gt; Cu (2.34, 2.24, 0.97 &amp; 0.24 mg.kg-1) &gt; Cd (2.31, 1.19, 1.33 &amp; 1.12 mg.kg-1) &gt; Cr (1458, 1136.12, 601.73 &amp; 211.6 mg.kg-1) in 100, 75, 50, &amp; 25% sludge amended soil, respectively. The bio-concentration pattern of metals was found to be in the order of root &gt; leaf &gt; stem. The findings of the present study give direction for the eco-friendly and cost-effective management of tannery sludge. Further, H. cannabinus can be used for the restoration of metal-contaminated agricultural land, however, results need to be corroborated with field trials.

Pharmacognostic, Physicochemical and Phytochemical analysis of Hibiscus cannabinus Leaves

The work deals with Pharmacognostic, physicochemical and preliminary phytochemical analysis of Hibiscus cannabinus L., (Malvaceae). The macroscopic and microscopic characteristics were observed namely physical constant values, ash values, and micro-chemical analysis. The presence of lignified cells, pericyclic fibers, stone cells, cuticles, calcium oxalate crystal, as seen in the powders of leaves. Physical constants like foreign organic matter, moisture content, ash content, acid-insoluble ash and water-soluble ash extractive values were determined the extracts shows presence of steroids, flavonoids, carbohydrates, alkaloid, glycosides, phenols, and tannins by phytochemical screening. The above study will highlighted characterize the pharmacognotical, physicochemical and preliminary phytochemical parameters of Hibiscus cannabinus Linn.

Fabrication of a hybrid composite of glass and kenaf fibers and investigation of its mechanical properties

In this research, agriculture residues as reinforcement and filler were utilized for an epoxy-based matrix material. Glass fibre was incorporated in this composite throughout the production process in addition to the kenaf fibre. Rice husk ash filler in the matrix was maintained at 10 wt %, while the kenaf/glass hybrid fibre varied from 0 to 40%. Compression moulding was used to create the hybrid to study its mechanical attributes, which includes tensile strength, flexural strength, and impact strength. The results showed that due to the wettability of the given hybrid matrix, it exhibits superior mechanical characteristics. For 30% hybrid fibre and 10% filler material, the mechanical properties like tensile strength, flexural strength, and impact strength were raised by 41.26%, 14.42%, and 63.15%, respectively.

Thermal Performance Study on Coconut Husk and Kenaf Fibre as Thermal Insulation Materials

Thermal Performance Study on Coconut Husk and Kenaf Fibre as Thermal Insulation Materials

The effect of isocyanate on the properties of poly(butylene adipate‐co‐terephthalate)/Kenaf fiber composites

AbstractPoly(butylene‐adipate‐co‐terephthalate) (PBAT)/Kenaf fiber composites was prepared by the melt processing technique with various compositions to investigate the general properties. While the Young's modulus of the composite was profoundly improved, the tensile strength and elongation at break exhibited a significant diminished with the incorporation of kenaf fibers due to the poor interfacial adhesion between PBAT and Kenaf fibers. The Halpin‐Tsai model was applied, and the similar behavior of Young's modulus for the composite as compared to experimental results was calculated. The micro‐voids and cavitation were clearly confirmed by morphological observation. Reactive compatibilization with HDI improved the compatibility between PBAT and Kenaf fibers, and the mechanical performance was significantly enhanced due to improved interfacial adhesion. The PBAT/Kenaf composites with a reactive compatibilization showed considerable improvement of storage modulus, G′ in terminal region as well. The stable thermal stability could be also beneficial for thermal processing technique. The addition of Kenaf fiber resulted in a liquid‐like behavior decreasing elasticity of the PBAT/Kenaf composites. The HDI had a profound effect on increasing elasticity with solid‐like behavior resulting in enhancing the G′ and η* of the PBAT/Kenaf fiber composites due to the improved interfacial adhesion as confirmed from the morphological observation.Highlights Kenaf fiber has a great effect on improvement of the modulus for PBAT/Kenaf composites The optimized PBAT/Kenaf composite composition is 96/4 wt% ratio for the composite HDI is found to be a good compatibilizer for PBAT and Kenaf fiber Reactive compatibilization enhances the interfacial adhesion between PBAT and Kenaf fiber The compatibilized PBAT/Kenaf composites have the better mechanical performance

Thermoplastic composites reinforced chemically modified kenaf fibre: current progress on mechanical and dynamic mechanical properties

Thermoplastic composites reinforced chemically modified kenaf fibre: current progress on mechanical and dynamic mechanical properties

Bio-based composite active film/coating from deccan hemp seed protein, taro starch and leaf extract: Characterizations and application in grapes

This study aimed to create a novel, cost-effective, and environmentally friendly food packaging film or coating using agricultural waste materials such as deccan hemp seeds and leaves. The process involved blending deccan hemp seed protein and leaf extract at an optimal ratio through a casting technique. Additionally, starch isolated from taro root was added into the protein-based film to enhance its structural, barrier, and mechanical properties. The introduction of bioactive compounds, like deccan hemp leaf extract, led to increase in antioxidant activity and enriching the film with beneficial phenolic compounds.The combination of leaf extract and starch with the protein film resulted in a homogeneous, dense, and smooth film matrix, as evidenced by scanning microscopy images. FTIR spectroscopy confirmed interlinkage among the various constituents in the film. Rheological analysis of the film-forming solution showed its shear-thinning behavior, with the storage modulus exceeding the loss modulus in the angular frequency range of 0.1 rad/s to 100 rad/s, indicating the film's elastic nature. Furthermore, the physical and optical attributes of the films were enhanced through the addition of starch and leaf extract.In a practical application, the film-forming solution was applied to grapes, leading to improved quality and extended shelf life for grapes stored under ambient conditions for ten days. Overall, this study's findings suggest that the use of deccan hemp seed protein-based packaging film holds promise as an emerging solution for enhancing the shelf life of vegetables and fruits, offering a sustainable and effective alternative for food packaging.

A cyclic nucleotide-gated channel gene HcCNGC21 positively regulates salt and drought stress responses in kenaf (Hibiscus cannabinus L.)

Cyclic Nucleotide-Gated Channels (CNGCs) serve as Ca2+ permeable cation transport pathways, which are involved in the regulation of various biological functions such as plant cell ion selective permeability, growth and development, responses to biotic and abiotic stresses. At the present study, a total of 31 CNGC genes were identified and bioinformatically analyzed in kenaf. Among these genes, HcCNGC21 characterized to localize at the plasma membrane, with the highest expression levels in leaves, followed by roots. In addition, HcCNGC21 could be significantly induced under salt or drought stress. Virus-induced gene silencing (VIGS) of HcCNGC21 in kenaf caused notable growth inhibition under salt or drought stress, characterized by reductions in plant height, stem diameter, leaf area, root length, root surface area, and root tip number. Meanwhile, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly decreased, accompanied by reduced levels of osmoregulatory substances and total chlorophyll content. However, ROS accumulation and Na+ content increased. The expression of stress-responsive genes, such as HcSOD, HcPOD, HcCAT, HcERF3, HcNAC29, HcP5CS, HcLTP, and HcNCED, was significantly downregulated in these silenced lines. However, under salt or drought stress, the physiological performance and expression of stress-related genes in transgenic Arabidopsis thaliana plants overexpressing HcCNGC21 were diametrically opposite to those of TRV2-HcCNGC21 kenaf line. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays revealed that HcCNGC21 interacts with HcAnnexin D1. These findings collectively underscore the positive role of HcCNGC21 in plant resistance to salt and drought stress.

Enhancing sustainable composites: isolation of nanocellulose from Selenicereus undatus (dragon fruit) and kenaf fiber reinforcement in vinyl ester matrix—a study on mechanical, wear, fatigue, creep, and dynamic mechanical properties

Enhancing sustainable composites: isolation of nanocellulose from Selenicereus undatus (dragon fruit) and kenaf fiber reinforcement in vinyl ester matrix—a study on mechanical, wear, fatigue, creep, and dynamic mechanical properties

Hybridization of woven kenaf and unidirectional glass fibre roving for unsaturated polyester composite

This is a study on the mechanical properties of kenaf/glass-reinforced polyester composites intended for use in structural profiles with a wall thickness by max. 6 mm. Mechanical properties such as tensile, compression, bending and interlaminar shear stress were investigated by comparing the hybrid variants with the pure fibreglass variant. According to the study, woven kenaf/unidirectional glass roving (WK/UG) alternate recorded the highest tensile properties among hybrid samples. It demonstrated a decrement of about 8.2% of the tensile strength (404.54 MPa) and 10.7% of tensile modulus (24.54 GPa) compared to conventional fibreglass samples. Alternating WK/UG samples demonstrated higher compressive strength (417.15 MPa) compared to other hybrid specimens, recording a slight decrease at 6.09% compared to pure fibreglass composites. The highest bending properties were also observed in hybrid alternate WK/UG samples among other hybrid laminates with only a decrement of 4.13% in modulus of rupture (456.33 MPa) and 1.9% in modulus of elasticity (14.49 GPa) when compared to the control specimen. The ILSS of hybrid composites 2WK/3UG/2WK (30.97 MPa) and WK/UG alternate (34.90 MPa) showed good agreement with the pure fibreglass (42.33 MPa) composites. Using SEM images, tensile fractured specimens were examined to comprehend composites’ failure mechanism and interfacial adhesion. Overall, woven kenaf/unidirectional glass roving alternate sequence is chosen as a potential alternative in developing structural profiles for moderate load-bearing structural applications. In contrast, 3WK/UG/3WK with a higher kenaf to glass ratio demonstrate potential in low load-bearing structural profile applications.Graphical abstract

Crushing Performances of Kenaf Fibre Reinforce Composite Tubes

The quest for sustainable and eco-friendly materials has led to a burgeoning interest in natural fibers as reinforcements in composite materials. Kenaf fiber, derived from the Hibiscus cannabinus plant, presents a promising avenue for enhancing the mechanical and energy absorption properties of composite tubes. This study focuses on the fabrication of composite tubes using a combination of kenaf fiber and epoxy resin. The composite tubes were then subjected to compressive testing to evaluate their energy absorption performances. The fabrication process involved the impregnation of kenaf fibre with epoxy resin, followed by winding and curing to form composite tubes. Different configurations of kenaf fiber content were utilized to investigate their impact on the structural integrity and energy absorption capabilities of the tubes. Compressive testing was conducted to assess the energy absorption behaviour under axial loading conditions. The results revealed that the incorporation of kenaf fiber significantly influenced the energy absorption capabilities of the composite tubes. Higher kenaf fiber content demonstrated improved energy absorption performance, showcasing the potential of kenaf fiber as an efficient energy-absorbing reinforcement. The findings of this study offer valuable insights into the use of sustainable and renewable resources, such as kenaf fiber, in enhancing the mechanical and energy absorption properties of composite structures, thereby contributing to the development of eco-friendly and high-performance materials.

An Experimental Study on the Low-Velocity Impact Behavior of Biopolymer-Coated Kenaf Fiber Reinforced Epoxy Nanocomposites: A Route to Sustainability

An Experimental Study on the Low-Velocity Impact Behavior of Biopolymer-Coated Kenaf Fiber Reinforced Epoxy Nanocomposites: A Route to Sustainability

Mechanical properties of Kenaf and Palmyra Palm leaf stalk fiber reinforced composite

The kenaf fibers and Palmyra palm leaf stalk fibers (PPLSF) fiber were extracted using retting process then the composite was fabricated by Hand lay-up process using chemically treated unidirectional bilayer fibers mat. The fabricated composites undergone with mechanical properties such as tensile, flexural, impact test, and hardness. Three types of composites were manufactured by varying the weight percentage of fiber content, the composites were: Kenaf-Palmyra Palm Leaf Stalk-Kenaf Fiber Composite (KPKFC), Palmyra Palm Leaf Stalk-Kenaf-Palmyra Palm Leaf Stalk Fiber Composite (PKPFC), and Palmyra Palm Leaf Stalk-Kenaf Fiber Composite (PKFC). The KPKFC and PKPFC had shown significant mechanical properties. The maximum tensile and impact strength was found for PKPFC, the tensile and impact strength was 10.60 MPa and 17.37 J/cm2 respectively. The PKPFC had almost 60.18% and 66.72% more tensile and impact strength than KPKFC respectively. The highest flexural strength was obtained for KPKFC and flexural strength was 19.38 MPa. The KPKFC had 49.12% more flexural strength than PKPFC. The maximum hardness was obtained for KPKFC and the hardness was 25.4 Shore D.

Experimental Investigation on Mechanical and Viscoelastic properties of Kenaf, Basalt and Carbon Fiber reinforced Hybrid Epoxy Polymer Composites

Abstract In this study, a hybrid polymer composite reinforced with natural fibers such as Kenaf and Basalt, as well as carbon fiber was developed and analyzed for mechanical properties of the composite with varying fiber content and orientation. The composites were made using a hand layup process in which the plies were alternately stacked. Further, specimens were cut from the fabricated laminate according to ASTM standards. For the tensile and flexural test was conducted using a Universal Testing Machine (UTM). It is noticed that a hybrid composite made up of both natural fibers and carbon fiber has shown greater strength than a composite made up of only natural fibers with the same volume percentage of fiber. Furthermore, it is observed that the hybrid fiber composite in equal proportion is shown maximized strength.

Impact of Molding Temperature, Fiber Loading and Chemical Modifications on the Physicomechanical, and Microstructural Morphology Properties of Woven Kenaf Fiber/PLA Composites for Non-Structural Applications

ABSTRACT These days, green composites are getting a lot of attention for their biodegradability, sustainability, and affordability. This study applies polylactic acid as the matrix and untreated and surface-treated kenaf fibers as reinforcement to fabricate kenaf-reinforced PLA-based composites. Kenaf fibers are exposed to three different chemical treatments (sodium hydroxide, potassium permanganate, and potassium dichromate) and investigate the effect of surface modifications on the mechanical properties of kenaf/PLA composites. The surface modified fibers were characterized by FTIR Spectroscopy. The consequences of processing variables such as fiber volume percent ranging from 25% to 50% and molding temperature range of 160°C to 180°C were also examined on the mechanical characteristics of developed composites and are validated using SEM analysis. Surface modifications result in improved tensile and flexural characteristics of developed treated kenaf/PLA composites. Alkali treated woven kenaf fiber composites with greater matrix adhesion have optimum tensile and flexural strength of 72.81 MPa and 94.45 MPa respectively. The present study revealed that composites (fabricated at 170°C molding temperature) have maximal tensile and flexural strength at 35% fiber volume fraction.

Antioxidant Activities in Kenaf (Hibiscus cannabinus) Shoots during Growth Stages and Destination of Chlorogenic Acid and Kaempferol Glycosides.

Apart from being utilized as a commercial fiber at maturity, kenaf shoots have potential as a food and feed source because of their diverse bioactivities. Previous studies have focused on mature stems because of their high biomass, whereas the antioxidant activities (AA) and the destination of AA contributors of kenaf stems and their high-yielding byproduct leaves during the growth stage have rarely been studied. Therefore, we investigated changes in AA and its relative components in kenaf leaves and stems during the four vital growth stages. Higher ABTS radical cation and DPPH radical scavenging abilities and ferric reducing antioxidant power, total phenolic content, total flavonoid content, and total polysaccharide content were observed at all leaf stages and in the late stem stages. Chlorogenic acid (CGA) and kaempferol glycosides, especially kaempferitrin (Kfr), were identified as representative phenolic acids and flavonoids in both kenaf leaves and stems. The content of CGA in both leaves and stems increased corresponding to the plant's growth stage, whereas kaempferol glycosides were enhanced in leaves but declined in stems. The highest correlation was observed between TPC and AA in all organs. Further evaluation of CGA and Kfr verified that CGA was the predominant contributor to AA, surpassing Kfr. These findings suggest that kenaf leaves increase antioxidant levels as they grow and can be a useful source of stem harvesting byproducts.

Evaluation and Analysis of Elastic and Mechanical Characteristics of Hybrid Composite Incorporating Banana Fiber, Kenaf Fiber, and Nano-CaCO3

Evaluation and Analysis of Elastic and Mechanical Characteristics of Hybrid Composite Incorporating Banana Fiber, Kenaf Fiber, and Nano-CaCO3

Isolation and characterisation of lignin using natural deep eutectic solvents pretreated kenaf fibre biomass

Extraction of lignin via green methods is a crucial step in promoting the bioconversion of lignocellulosic biomasses. In the present study, utilisation of natural deep eutectic solvent for the pretreatment of kenaf fibres biomass is performed. Furthermore, extracted lignin from natural deep eutectic solvent pretreated kenaf biomass was carried out and its comparative study with commercial lignin was studied. The extracted lignin was characterized and investigated through Infrared Fourier transform spectroscopy, X-ray Diffraction, thermogravimetric analysis, UV–Vis spectroscopy, and scanning electron microscopy. FTIR Spectra shows that all samples have almost same set of absorption bands with slight difference in frequencies. CHNS analysis of natural deep eutectic solvent pretreated kenaf fibre showed a slight increase in carbon % from 42.36 to 43.17% and an increase in nitrogen % from − 0.0939 to − 0.1377%. Morphological analysis of commercial lignin shows irregular/uneven surfaces whereas natural deep eutectic solvent extracted lignin shows smooth and wavy surface. EDX analysis indicated noticeable peaks for oxygen and carbon elements which are present in lignocellulosic biomass. Thermal properties showed that lignin is constant at higher temperatures due to more branching and production of extremely condensed aromatic structures. In UV–VIS spectroscopy, commercial lignin shows slightly broad peak between 300 and 400 nm due to presence of carbonyl bond whereas, natural deep eutectic solvent extracted lignin does not show up any peak in this range. XRD results showed that the crystallinity index percentage for kenaf and natural deep eutectic solvent treated kenaf was 70.33 and 69.5% respectively. Therefore, these innovative solvents will undoubtedly have significant impact on the development of clean, green, and sustainable products for biocatalysts, extraction, electrochemistry, adsorption applications.