Kenaf Bast Fiber Research Articles

Effects of kenaf core and bast fibers as dispersing phases on low density fiberboards (engineered wood)

Fiberboards are engineered woods made from a composition of wood chippings, wood fibers, sawdust etc., glued together with adhesives. Low density fiberboards (LDF) are part of the classes of fiberboards widely used in Nigeria because they are readily available, relatively cheap and offer good aesthetic values, compared to conventional woods. However, they possess low strength, durability and lifespan, thus making them susceptible to damage during service. The aim of this study was to determine the effect of kenaf core and bast fibers (Hibiscus cannabinus) as one of the dispersing phases in low density fiberboard production, also known as particleboards. The materials and methods employed in the study, followed procedures in established standards and literatures. The different composite materials were weighed and mixed properly for about 10 minutes to ensure homogeneity in the mixture. Thereafter, the materials were placed in a mould of uniform thickness and compressed to different fiber board samples using a compression press machine, for about 10mins. A series of physio-mechanical tests such as water absorption, density, tensile strength, modulus of elasticity and modulus of rupture were conducted on the developed fiberboard samples as well as the control samples. The results showed that the average values for water absorption and density of the developed samples enhanced with kenaf core and bast fibers were 5.480% and 0.027 g/cm3 respectively. These values compare well with that of the control samples. Also, the tensile strength, modulus of elasticity and modulus of rupture of samples enhanced with kenaf gave average values of 31.842 MPa, 2.920 GPa and 16.58 N/mm2 respectively. These values also compare well with that of the control samples. From the results gotten and all the properties determined, the study showed that kenaf core and bast fibers can be employed appreciably as dispersing phases for low density fiber board (LDF) composite production.

Effect of Fiber Loading on Mechanical and Physical Properties of Uniaxial Long Kenaf Bast Fiber Reinforced Epoxy Composites

In the recent years, due to environmental awareness of general public, researchers and scientists directed towards the use of natural fibers reinforced composites as environmentally friendly. Now a days, many scientists, researchers and engineers have explored the extraction, properties and utilization of natural fibers as economically and effectively as possible to produce good quality natural fiber reinforced polymer matrix composites. Many scientists and researchers proved that increase in fiber loading resulted in increased mechanical properties of the composite material. This will be the basis to develop and to evaluate properties of natural fiber reinforced polymer matrix composites. In this research, Kenaf long fiber reinforced epoxy matrix composites were successfully fabricated by simple and cost effective hand layup technique and their mechanical properties such as tensile strength, bending strength, impact strength, hardness with different fiber loading were successfully investigated. Water absorption capacity was also reported. The fibers are treated with NaoH solution for surface modification and to improve mechanical properties. The specimens are prepared according to ASTM standard and experiments were carried out.

Analysis of the Relationship Between Enzymatic Activity and Microbial Degumming Effect of Kenaf Bast

ABSTRACT Degumming is the most important step before kenaf bast fibers used in textile industry. Microbial degumming is an environmental protection and energy-saving technology to replace the conventional chemical degumming. Higher efficiency strains are the essential prerequisite to promote the application of microbial degumming technology. Generally, the screening and evaluation of strains for kenaf bast degumming were based on activity of functional enzymes produced by microorganism. In order to investigate the relationship between enzymatic activity and effect of kenaf bast degumming, strains DCE-01, 1101, B6, B7, and B8 were incubated in pure cultured, sterilized and non-sterilized degumming systems. After culturing for 16 h, functional enzymes for kenaf bast degumming (such as pectinase, neutral protease, xylanase, β-mannanase, laccase, lignin peroxidase and manganese peroxidase) were detected in the supernatant, and degumming effect of kenaf bast under sterilized and non-sterilized systems were evaluated respectively. Results revealed that strain DCE-01 was the best for kenaf bast degumming, though its enzymatic activity was not the highest among five strains. And the pretreatment of kenaf bast by high-pressure-steam sterilization could promote the degumming effect. This study suggested that there were limitations when screening or evaluating high-efficient strains for kenaf bast degumming with the guidance of enzymatic activity.

Estimation of the Effects of the Cross-Head Speed and Temperature on the Mechanical Strength of Kenaf Bast Fibers Using Weibull and Monte-Carlo Statistics

Methods used by different researchers to evaluate plant fibers’ (PFs) mechanical performance, show great variance in results. In this work, 320 single kenaf fibers of gage lengths 10 and 20 mm were tensile-tested using four speed levels (0.05; 0.5; 1 and 5 mm·min−1). Sixty-three other specimens were also tested under three temperature levels (50, 100, and 150 °C). Mechanical characteristics, namely Young’s modulus, tensile strength, and failure strain were determined. Estimation of the dispersion on the data was performed using Weibull and Monte-Carlo statistics. Results showed a low scatter for cross-head speeds of 0.05, 0.5, and 1 mm·min−1, compared to 5 mm·min−1 for the two gage lengths used. Monte-Carlo average failure strength values were found to be close to the experimental values. A drastic drop in the tensile strength was observed for the temperature of 150 °C for varying hold times. The reported findings are likely to be used in the elaboration of a tensile test standard on PFs.

Preparation of Fibrillated Cellulose from Kenaf Bast Fiber using High Speed Homogenizer without Pressure

The aim of the study is to characterize the fibrillated cellulose (FC), which has been extracted from kenaf bast fiber using high speed homogenizer (HSH). The FC was prepared by applying 10,000, 15,000 and 20,000 rpm of homogenization process for 10, 15 and 20 mins. Morphological observation via Field Emission Scanning Electron Microscope (FESEM) was carried out in order to observe the sur-face morphology of FC while Fourier Transform Infrared (FTIR) spectroscopy was performed to determine the changing of functional groups. Thermogravimetric Analysis (TGA) was done for thermal decomposition of FC. Results showed that the diameter of the FC from kenaf bast was determined below 100 nm. The Fourier Transform Infrared (FTIR) spectroscopy showed that lignin and hemicellulose were almost completely removed during the bleaching process at peak 1,737 cm-1. In addition, thermogravimetric analysis (TGA) displayed 272°C as the highest temperature for thermal stability of FC. In conclusion, by controlling the speed during homogenization process, FC was successfully obtained. Such FC can be applied as beneficial main ingredients in papermaking and packaging industry, which dedicat-ed to mechanical strength properties.

Palm oil-based biodiesel synthesis by radiation-induced kenaf catalyst packed in a continuous flow system

An efficient bio-based heterogeneous catalyst for biodiesel production was successfully fabricated by radiation-induced graft polymerization of 4-vinylbenzylchloride (VBC) followed by quaternary amination of trimethylamine (TMA) and ion-exchange with aqueous sodium hydroxide onto kenaf bast fiber using electron beam irradiation at a dose of 150 kGy. The produced catalyst was characterized by FESEM–EDX, CHNS, ATR-FTIR, TGA and XRD analyses. In this study, the continuous catalytic transesterification of triolein/ethanol in a bench-scale packed bed reactor (PBR) was designed and tested. The reaction process was focused at room temperature, different residence times from 1 min to 4 min and a molar ratio of triolein/ethanol (1:50). Besides, study on the transesterification of palm oil with ethanol under optimized conditions for maximum conversion of triolein to ethyl oleate (residence time of 3 min, LHSV = 8 h−1, short chain 150kGy catalyst) with temperature fixed at room temperature (˜25 °C) has been carried out. The extracted ethyl oleate was analyzed by HPLC and ATR-FTIR. The results found that the continuous flow system has a great potential for producing ethyl ester to be used as biodiesel and it is possible to generate 100% biodiesel with high purity from palm oil using radiation-induced kenaf catalyst.

Synthesis, characterization and cytotoxicity studies of nanocrystalline cellulose from the production waste of rubber-wood and kenaf-bast fibers

In the present study, nanocrystalline cellulose (NCC) was successfully prepared from raw rubberwood fiber (RRaw) and raw Kenaf-bast fiber (KRaw) via a series of multi-step chemical-mechanical purification techniques, namely, alkalization treatment, hydrogen peroxide bleaching and acid hydrolysis. The obtained nanocellulose yields were 27.51% and 32.53% for RRaw and KRaw, respectively. The crystallinity index of the RRaw and KRaw based nanocellulose increased from 61.21% to 74.34% and 54.12% to 73.19%, respectively, after acid hydrolysis. Morphological characterization by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) clearly showed the formation of rod-shaped NCC with an average diameter of 5.14 ± 1.91 nm and 5.27 ± 2.38 nm for RRaw and KRaw, respectively. Their size distributions significantly reduced compared to raw cellulose biomass fiber and extracted cellulose (EC). Furthermore, changes in the Fourier transform-infrared (FTIR) peaks showed that amorphous regions (e.g. hemicelluloses and lignin) were successfully removed from the fibre surface. The thermogravimetric analysis (TGA) of as-synthesized NCC confirmed its thermostability. Cytotoxicity tests demonstrated that NCC did not exhibit cellular toxicity upon exposure to macrophages (RAW 264.7) and HaCaT cells up to 700 µg mL−1.

Experimental investigation on drag reduction of flowing crop suspensions of the pulp fibers in circular pipe heat exchanger

Pressure drop measurements were obtained for different kenaf bast pulp fiber suspensions flowing through a circular pipe heat exchanger test loop. The data were generated from the flow loop over a selected range of flow rates and fiber concentrations. It was found that the magnitude of the pressure drop of the kenaf bast fiber suspensions is dependent on the characteristics, concentration, and pulping method of fibers. Considerable drag reduction is obtained for concentrations of 0.6 mass% at high flow rates. Such a reduction of pressure drop is significant for the design and optimization of crop fiber handling equipment and the relevant piping systems. Furthermore, the effects of various fiber processing techniques, fiber properties, and flexibility on pressure drop were studied in relation to the influence on fiber suspension properties.

Effect of surface treatment of natural reinforcement on thermal and mechanical properties of vinyl ester/polyurethane interpenetrating polymer network-based biocomposites

Kenaf fibre-reinforced vinyl ester (VE)/polyurethane (PU) interpenetrating polymer network (IPN)-based composites were made by hand lay-up technique. The kenaf bast fibre was chemically treated with 3, 6 and 9% vinyl silane. Treated fibres were characterized in terms of crystallinity, mechanical strength, density, thermal property and morphology. In comparison with the untreated fibre, 6% silane-treated fibres showed 25.4% higher % crystallinity, 66.9% increase in modulus elasticity and 604.2% increase in tenacity. Comparison of the pure VE with VE/PU IPN showed that the IPN had 3.3% lower modulus but 26.4% higher toughness than the former. Composites based on pure VE matrix and VE/PU IPN matrix were manufactured with the variation of untreated and treated fibre loading as 15, 20, 25, 30, 35 and 40 wt%. Novelty of this work lies in the modification of both the fibre surface and the matrix system simultaneously with the aim of increasing the adhesion between the fibre surface and matrix material of the composite. Composites with untreated fibres showed poor strength compared to that with modified fibres having corresponding compositions. IPN-based composites, with 35 wt% silane-treated fibre, showed improvement in tensile modulus by 16.61% and flexural modulus by 6.35% than pure VE-based composites with corresponding fibre loading.

Mechanical Characteristics of Green Composites of Short Kenaf Bast Fiber Reinforced in Cardanol

In this experiment, thermoset cardanol resin was reinforced with short kenaf bast fibers to produce 100% green composites. Different fiber loadings based on weight ratios (0%, 30%, 40%, 50%, and 60%) were fabricated by the hand layup method followed by compression molding. The results indicated that 50UTK (untreated kenaf fibers) displays the highest mechanical properties (91.9% and 43.4% increment for tensile strength and impact strength, respectively) compared with the brittle cardanol polymer and other combinations of composite. This indicates a great load transfer mechanism by kenaf fiber reinforcement due to good fiber/matrix interface shown in scanning electron microscope (SEM) analyses. On the contrary, short kenaf fiber insertion creates a stress concentration spot at the fiber’s end causing slightly lower flexural properties. Besides, high processing temperature has caused damage to the fibers and made further reduction of flexural strength. Therefore, a better load transfer mechanism has been compensated by negative influences of kenaf fiber insertion. In conclusion, 50 wt% of kenaf fiber insertion is found to be the optimum loading for cardanol matrix.

Preparation of Kenaf Bast Fibre Dispersions for Use in Latex Products

The use of kenaf has been extensively explored since its introduction in 1999 by the Malaysian government. However, its lacking application in rubber latex motivates the present study on preparation of kenaf bast fibre dispersions for the latex based industry. The fibres were first dry ground using four stainless steel sieve rings with different trapezoidal perforated diameters. This was followed by treatment of the smallest fibres with various concentrations of potassium hydroxide (KOH). Upon optimisation of the KOH concentration, the fibres were ball milled for 56 h to further reduce its size. The resulting dispersions were characterised to obtain their diameter and distribution, zeta potential, pH, morphology and rheology, respectively. The dry grinding process significantly reduced fibre sizes and the highest reduction observed was 80 μm using the smallest (0.08 mm) stainless sieve ring. Treatment of these fibres with increasing concentrations of KOH resulted in darkening of fibre colour, increased separation of the fibre layers, improvement in zeta potential and reduction in flow properties. Ball milling the bast fibres contributed to a further reduction in fibre size, with those in water reducing from 80 μm to 5 μm and that of fibres in 20 wt% KOH reducing from 80 μm to 8 μm. Optical microscopy also showed well dispersed bast fibres after 56 h milling. Compared to the ball milled fibres in water, zeta potential and flow properties were higher for the ball milled fibres in 20 wt% KOH. Similarly, the maximum packing concentration (φp) of the bast fibres in 20 wt% KOH was also slightly higher with a φp of 13.11 wt% compared to the bast fibres dispersed in distilled water with a φp of 12.45 wt%.

The Influences of Fibre Parameters on the Tensile and Flexural Response of Lightweight Thermoplastic Kenaf Fibre Reinforced Metal Composites

ABSTRACT The increasing demand for high performance and lightweight materials has stimulated the development of alternative materials, namely fiber metal laminates (FMLs). FML is a sandwich structure which is formed by bonding the metallic layers with composite as core constituent using an adhesive agent. In this study, the mechanical behavior of FMLs with the core constituents of environmental friendly kenaf bast fiber reinforced polypropylene composites bonded with aluminum skin layers was investigated. The effects of fiber compositions (50, 60, and 70 wt.%), fiber lengths (30, 60, 90 mm), and alkali treatment on the mechanical responses of FML were investigated. The overall results revealed that the increase of fiber composition and fiber length reduces the mechanical strength of FML owing to the agglomeration of natural fibers when the fiber length exceeds the critical limit. However, the chemical treated kenaf bast fiber reinforced FML showed a significant enhancement of the mechanical properties in comparison to the non-treated fiber reinforced FML owing to the improved fiber-matrix adhesion level.

Effect of Modification Time of Kenaf Bast Fiber with Maleic Anhydride on Tensile Properties of Kenaf-Glass Hybrid Fiber Unsaturated Polyester Composites

Natural fiber reinforced polymer composites are generally lower in mechanical performance compared to synthetic fiber reinforced polymer composites. However, this disadvantage can be improved via chemical modification of the natural fiber and hybridization with synthetic fiber. In this study, kenaf bast fiber was used as reinforcement in unsaturated polyester composites. It was subjected to chemical modification with maleic anhydride at various treatment time i.e. 60, 90 and 120 minutes prior to composites production. The untreated and MA treated kenaf bast fiber were hybridized with 10 weight percent of glass fiber to produce kenaf bast/glass fiber reinforced unsaturated polyester composites. The effect of treatment time on weight percent gain and functional group changes via infra-red spectra of kenaf bast fiber were investigated. The effect of treatment time on tensile properties of kenaf bast fiber and kenaf bast/glass fiber reinforced unsaturated polyester composites were also studied. It was revealed that the weight percent gain of kenaf bast fiber increased with the increasing of treatment time. The increasing of treatment time resulted in the enhancement of tensile strength and modulus of kenaf bast fiber and kenaf bast/glass fiber reinforced unsaturated polyester composites which were attributed to the presence of C=C bonds of maleic anhydride and has been proven through fourier transform infrared spectrum.

Kenaf Fibrous Concrete: Mechanical Properties with Different Fiber Volume Fraction

Kenaf fiber comes from Kenaf plant which grows thrivingly in hot and humid temperature. The origin of Kenaf comes from a few different countries that have similar characteristics such as Africa, China, and India. Kenaf or its scientific name, hibiscus cannabinus is a beneficial crop where the seeds and stems can be used in various industries such as medicine, paper production and composite material. Kenaf core and bast fiber can reach up to 3 meters long and this is an essential reason to corporate Kenaf with other composite material like polymer and concrete. This paper indicates the investigation of finding an optimum value of Kenaf Fibrous Concrete with fiber volume of 0%, 0.5%, 0.75%, 1% and 1.5% in the mix proportions. The mechanical properties of fresh and hardened samples were tested during 7th and 28th day of curing in water. Compressive strength, splitting tensile and flexural strength tests were executed in accordance of BSEN 12390-3:2009, ASTM C496M-06 and BSEN 12390-5:2009 respectively, with different volume fractions in finding an optimum value of Kenaf Fibrous Concrete. The result shows that kenaf fiber has the hydrophilic characteristic that influences more water absorption in the mix proportions. The capability of this fiber improves the tensile strength and ductility because of the inclusion of fiber. However, it decreases the concrete compressive strength.

Diversity and Characteristics of Kenaf Bast Degumming Microbial Resources

ABSTRACTKenaf is one of the most important natural fiber crops. Traditional degumming with water retting causes serious environmental pollution and reduces the quality of fiber products. The development of kenaf industry is hindered by high production cost. Microbial degumming is suitable for kenaf bast degumming because of its high efficiency, energy conservation, low pollution, and high quality, among others. Through enrichment and screening from water sample, soil sample, and humus sample, we concentrated and identified 92 bacterial strains that could degrade kenaf bast colloid. The strains belonged to 11 genera and 16 species. Five of these strains did not produce cellulase and the weight loss rate of the kenaf bast fiber raw material was more than 20%. These strains belonged to Bacillus subtilis, Paenibacillus polymyxa, Clostridium acetobutylicum, Bacillus alcalophilus, and Erwinia chrysanthemi and were assigned with serial numbers from K1–K5, respectively. This study is the first to report the function of Bacillus pumilus, B. alcalophilus, Clostridium tertium, Brevibacillus brevis, Pectobacterium carotovora, E. chrysanthemi, and Tyromyces subcaesius in kenaf bast degumming. Pectinase and mannanase were the key enzymes in the degumming of kenaf bast.

Preparation and Characterization of Sol-gel Silica-modified Kenaf Bast Microfiber/Polypropylene Composites

The present study was conducted to determine the influence of the chemically modified kenaf bast fiber (KBF) on the mechanical, morphological, and thermal properties of fiber-reinforced polypropylene composites. The KBF was modified via the in situ sol-gel silica process through soaking the KBF in tetraethyl orthosilicate (TEOS) at a pH of 11, room temperature (25 °C ± 1 °C), and a KBF to TEOS ratio of 1:10 for 24 h. Silica successfully formed on the surface of the KBF. Subsequently, the sol-gel silica-modified KBF was utilized to produce sol-gel silica-modified KBF-reinforced polypropylene (PP-KBF-S) composites. Several analytical methods were utilized to determine the mechanical, morphological, and thermal properties of the PP-KBF-S composites, which were then compared with those of the untreated KBF-reinforced polypropylene composite. The findings revealed that sol-gel silica modification of the KBF reduced the void content and enhanced the mechanical properties and thermal stability of the PP-KBF-S.

The effect of alkali treatment under various conditions on physical properties of kenaf fiber

Alkali treatment was known as one commonly used treatment for natural fiber and obtained a good fiber matrix adhesion, thermal and mechanical properties of composite. This paper reports the effect of alkali treatment conditions on the physical properties of kenaf fiber such as density, weight loss, diameter, cross sectional and fiber morphology. In this study, kenaf fiber were treated under various conditions alkali concentration at 2, 6 and 10 (w/v%), immersion duration at 30, 240 and 480 minute and immersion temperature at 27, 60 and 100°C. The effects of alkali treatment on kenaf fiber physical properties under various conditions were explored. Alkali treatment conditions setting have an impact on kenaf bast fiber physical characteristics. In kenaf fiber density, it was found that a small increase of kenaf density value after alkali treatment compared to untreated kenaf fiber. When each of alkali treatment parameters increased, kenaf fiber density also increased slightly. Kenaf fiber weight loss also exhibit a similar pattern of small increment with the increase of treatment parameters. Additionally, kenaf fiber diameter and cross sectional area show a decline pattern after treated with alkali. Furthermore, this decline pattern was corresponding with the increasing level of alkali treatment parameters. The maximum of kenaf diameter reduction was recorded at high level of each alkali treatment parameters.

THE ALKALI TREATMENT PARAMETERS USING TAGUCHI MODEL IN ORDER TO OBTAIN THE OPTIMUM TENSILE STRENGTH OF SINGLE KENAF FIBER

The development of high-performance engineering products made from natural resources is increasing worldwide. Kenaf plants have been extensively exploited over the past few years. Chemical treatment is considered to modify the fiber surface properties. In this study, kenaf bast fibers were treated with various concentrations of NaOH with different immersed time, immersed temperature, and dried temperature. Fiber bundle tensile were performed to evaluate the effect of treatments on the fiber tensile strength. Taguchi Methods are used in order to obtain the optimal parameter which could affect the tensile strength of kenaf fibers. Three-Level Orthogonal array is used to design the experiment. Finally, the experimental results will be evaluated using analysis of variance (ANOVA). The analysis of variance (ANOVA) shows that the most significant alkali parameter is NaOH concentration, which accounts for 40.19 percent of the total. It is also found that the optimum treatment is kenaf immersed in 3 wt. percent NaOH solution for 1 hour at 33 degrees celcius and dried at 60 degrees celcius which is supported by the Fourier Transform Infrared Spectroscopy.

Woven hybrid Biocomposite: Mechanical properties of woven kenaf bast fibre/oil palm empty fruit bunches hybrid reinforced poly hydroxybutyrate biocomposite as non-structural building materials

Green or Biocomposite materials encompass biopolymers and natural fibers (NFs) from renewable resources, which is helped to eliminate non-renewable waste, reduce raw material usage, and lessen greenhouse gas emissions. This paper aimed to assess and develop specific biocomposite in terms of mechanical properties, which prepared by lamination and compression molding method. The woven kenaf bast fibre (KBFw) is deliberated as reinforcement in this study due to the high tensile strength which was hybridized with oil palm empty fruit bunches (EFB) due to high toughness of EFB for covering the impact properties of biocomposite. The polyhydroxybutyrate (PHB) is a common biodegradable polymer that is targeted as matrix for green composite. The triethyl citrate (TEC) was chosen as plasticizer for improving flexibility and handling of PHB films. The scanning electron microscope was used to understand and investigate the tensile-fractured surface of different hybrid biocomposite. The results show that the tensile and flexural properties would be increase when NFs with higher tensile strength was used as skin fibre in term of hybrid composite. Conclusively, the flexural stiffness of biocomposite increase when the KBFw PHB biocomposite is hybrid with FEB reinforcement. The tensile and flexural test of KBFw/EFB hybrid reinforced PHB biocomposite with 11 layers (sample E) is determined that sample E has capability to replace with some wood and woody production.

Influence of nano-sized fumed silica on physicochemical and electrochemical properties of cellulose derivatives-ionic liquid biopolymer electrolytes

Nanocomposite biopolymer electrolyte was prepared by solution-casting technique. Carboxymethyl cellulose from kenaf bast fibre, ammonium acetate, (1-butyl)trimethyl ammonium bis(trifluoromethylsulfonyl)imide ionic liquid and silica nanofiller was used to prepare the biopolymer electrolyte samples. The films were characterized by Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, scanning electron microscopy, transference number measurement and linear sweep voltammetry. The interactions of doping salt, ionic liquid and inorganic nanofiller with the host biopolymer were confirmed by FTIR study. The highest conductivity achieved was 8.63 × 10−3 S cm−1 by the incorporation of 1 wt% of SiO2 at ambient temperature. The electrochemical stability of the highest conducting sample was stable up to 3.4 V, and the ion transference number in the film was 0.99.