Kenaf Fiber Composites Research Articles

Experimental and modeling investigation of the acoustic behavior of sustainable kenaf/yucca composites

The increased awareness of environmental issues has motivated researchers and manufacturers towards the use of natural acoustic absorbers, which are environmentally friendly, sustainable, and relatively cheap. One approach in this direction is to explore the use of waste fibers for potential applications in sound absorption. This study investigates the acoustic behavior of kenaf and yucca waste fiber composites. To this end, yucca and kenaf waste fibers were collected. The separation and extraction of fibers from non-fibrous tissues and woody parts were carried out using the water retting technique. Afterward, yucca and kenaf fibers were blended with a mass ratio of 70:30, 50:50, and 30:70. Polyvinyl alcohol (PVA) was used as the binder to fabricate the composite samples. The acoustic performance of the composites was evaluated using the impedance tube technique. The frequency-dependent absorption behavior of the samples was also investigated using the Delany-Bazley (D-B), Garai-Pompoli (G-P), and Johnson-Champoux-Allard (JCA) models. An in-house developed Matlab code was used for the simulation of the 3D structure of the specimens, and flow resistivity was calculated by simulation of the airflow through the structure. Additionally, tortuosity, viscous, and thermal characteristic lengths were calculated by an inverse technique. It was found that samples of 100% kenaf fibers have the highest flow resistivity values. Flow resistivity decreased with decreasing the kenaf content in the composite samples. It was found that samples of 100% kenaf fibers exhibit promising performance at the low- and mid-frequency bands. A decrease in the amount of kenaf content led to the shift of absorption peak towards the high-frequency region. It was also found that the JCA model closely follows the trend of experimental data for the frequency range of 80–6300 Hz.

The Effect of Alkali Treatment on Physical, Mechanical and Thermal Properties of Kenaf Fiber and Polymer Epoxy Composites.

The use of kenaf fiber as a reinforcement material for polymer composites is gaining popularity, especially in the production of automotive components. The main objective of this current work is to relate the effect of alkali treatment on the single fiber itself and the composite material simultaneously. The effect of temperature condition during mechanical testing is also investigated. Composite materials with discontinuous natural kenaf fibers and epoxy resin were fabricated using a compression moulding process. The epoxy composites were reinforced with 50 wt% untreated and treated kenaf fibers. The kenaf fiber was treated with NaOH solution (6% by weight) for 24 h at room temperature. Kenaf fiber treated with NaOH treatment had a clean surface and no impurities. For the first time we can see that alkali treatment had a damaging effect on the mechanical properties of kenaf fibers itself and the treated kenaf/epoxy composites. The composite reinforced with untreated kenaf fiber and treated kenaf fiber showed increased tensile strength (72.85% and 12.97%, respectively) compared to the neat epoxy. Reinforcement of the composite with treated kenaf fiber decreased the tensile strength due to the fiber pull out and the formation of voids which weakens the adhesion between the fibers and matrix. The temperature conditions also play an important role in composites with a significant impact on the deterioration of composite materials. Treated kenaf fiber has thermal stability and is not sensitive to temperature and as a result reinforcement with treated kenaf gives a lower loss value of 76%.

Effect of alkaline treatment on water absorption and thickness swelling of natural fibre reinforced unsaturated polyester composites

Environmental benefits and amazing performance can be obtained by utilizing palm oil fibres and kenaf fibres which illustrate colossal potential in fibre reinforced composites. An investigation has been made to determine the effects of alkaline treatment on water absorption and swelling behaviour of palm oil fibre composites as well as kenaf fibre composites. Untreated and treated natural fibres and were prepared in random orientation with different volume fraction of palm oil fibres and kenaf fibres; 30%, 40%, and 60. All the treated fibres were treated with 1 w/v% and 5 w/v% of sodium hydroxide concentration. Water absorption test was performed by immersing the sample in the distilled water periodically measuring the sample weight. Thickness swelling test was carried out by measuring the thickness of the specimens before and after soaking in the distilled water within certain period of time. All specimens were observed under Scanning Electron Microscope (SEM) to study the fibre morphology. TPOF_30_5SH achieved the least percentage of water absorption (1.44%) when it was compared with the UPOF_30 and TPOF_40_1SH. UPOF_60 shows the highest percentage of thickness swelling (8.96%). TPOF_30_5SH and TPOF_40_5SH show reduction of water absorption when they were compared with UPOF_30 and UPOF_40 respectively. All the treated kenaf fibre composites with 5 w/v% sodium hydroxide concentration such as TKF_30_5SH, TKF_40_5SH and TKF_60_5SH show improved result of thickness swelling. Materials covering the surface of palm oil fibres and kenaf fibres were more effectively removed with 5 w/v% sodium hydroxide than by treatment with 1 w/v% sodium hydroxide while observing under SEM.

The effect of graphene addition on the Young’s modulus and tensile strength of kenaf fibre composites

Natural fibres such as kenaf fibres may be used to reinforce polymer matrices such as polypropylene (PP). Such composite materials are in demand for the production of interior components for automotive vehicles due to their low density (1.2 g/cm³) and good mechanical properties (Young’s modulus of 11 GPa and tensile strength of 780 MPa). The main objective of this study is to determine the effect of the addition of graphene fillers to the tensile strength and Young’s modulus of kenaf fibre composites. For this kenaf/graphene/polypropylene (PP) composites are to be studied via computer simulations using Abaqus CAE software and to compare the experimental data of Young’s modulus and tensile strength of the composite from previous researchers with the results of the simulations. For the Abaqus CAE simulations, general static and dynamic explicit analyses were conducted and set at 20 wt. % kenaf fibres, 0, 1, 3, to 5 wt. % graphene. The highest value of Young’s modulus was 1 600 MPa achieved with the material with composition of PP/kenaf/graphene 5 wt. % while the highest value of tensile strength was achieved by the composition of PP/kenaf/graphene 1 wt. % at 23.07 MPa. On the other hand, the values of tensile strength increase with the addition of graphene (1 wt. %) at first due to the improvement of interface adhesion between the polymer matrix and non-organic particles. Further addition of graphene content (3 – 5 wt. %) results in a decrease of tensile strength due to the presence of agglomeration and defects such as voids and fibre pull-outs which weakens the adhesion between the fibres and matrix. The addition of graphene to PP/kenaf composites was proved to improve the Young’s modulus and tensile strength of the materials. This improves the suitability of the materials in the production of interior components for automotive vehicles.

Investigation of Mechanical Properties of Honeycomb Sandwich Structure with Kenaf/glass Hybrid Composite Facesheet

ABSTRACT The application of a sandwich structure made with composite facesheet and honeycomb core has increased rapidly due to high stiffness to weight ratio characteristics. There is a growing interest in using natural/synthetic hybrid composite to enhance the mechanical performance of natural fiber and reduce the environmental impact compared to synthetic materials. This study investigates the mechanical properties (tensile, edgewise compression, flexural) of the honeycomb sandwich structure with the hybrid composite facesheet, reinforced with different kenaf and glass fiber ratios. Non-hybrid kenaf and glass fiber composites were fabricated for comparison. The result showed that increasing the glass fiber ratio in a hybrid facesheet significantly improved the mechanical performance of the sandwich structure. Compared to the non-hybrid kenaf composite, the hybrid composite showed improved tensile and compression strength by up to 233% and 79%, respectively. The hybrid composite (glass/kenaf/glass) achieved 76% tensile modulus and 87% compression strength of glass fiber composite when the results were normalized. The specific flexural stiffness of the hybrid facesheet using glass fiber in the outer layer exhibited comparable performance by obtaining 89% flexural stiffness of non-hybrid glass composite sandwich structure.

Effect of glass fibre hybridization on the water absorption and thickness of alkali treated kenaf-epoxy composites

Abstract Natural and synthetic fibre reinforced hybrid polymer composites have attracted significant attention due to their combined benefits of biodegradability and strength. Kenaf fibres have the potential to replace synthetic fibres in polymer composites due to their excellent mechanical properties. However, their use for high strength and water resistance applications are not found suitable due to their hydrophilic nature. The main aim of this study is to reduce the water absorption capacity of kenaf fibre composites through alkali treatment and glass fibre hybridization. The continuous fibre, alkali treated, unidirectional kenaf-glass–epoxy hybrid composites (K untreated, K Treated, G/K/G, G/K/G/K/G, G) were prepared by the hand lay-up method and their water absorption and thickness swelling behaviour studied. Thereafter the diffusion properties like diffusion coefficient (Dc), corrected diffusion coefficient (Dcc), sorption coefficient (Sc) and permeability coefficient (Pc) of above composites were also calculated. The results show that alkali treated hybrid composites with stacking sequence G/K/G/K/G exhibited the lowest water absorption and thickness swelling capacity in comparison to kenaf fibre composites. The alkali treated kenaf fibre composites reduced the water absorption and thickness swelling capacity by 23% and 13% respectively compared to untreated kenaf fibre composites while the glass fibre hybridization further reduced the water uptake and thickness swelling by 35% and 32% respectively as compared to alkali treated kenaf fibre composites.

Effect of stacking sequence on dynamic mechanical properties of Indian almond – Kenaf fiber reinforced hybrid composites

ABSTRACT In this investigation, the dynamic mechanical properties of Indian almond – Kenaf fiber composite were investigated and the effect of stacking sequence was analyzed. Four types of composites viz. kenaf, Kenaf/Indian almond/Kenaf, Indian almond/Kenaf/Indian almond, and Indian almond were fabricated by hand layup technique. The experimental results revealed that the kenaf fiber composite showed the superior storage modulus and loss modulus values compared to all other composites due to the high stiffness of kenaf fiber and better bonding between the matrix and fiber. Among hybrid composites, Kenaf/Indian almond/Kenaf composite displayed a greater storage modulus and loss modulus than Indian almond/Kenaf/Indian almond composite due to the presence of two layers of high stiffness kenaf fiber. Further, the order of thermal stability of the composites was observed as: Kenaf > Kenaf/Indian almond/Kenaf > Indian almond/Kenaf/Indian almond > Indian almond. In addition, the Indian almond fiber composite and Indian almond/Kenaf/Indian almond composite exhibited good damping properties than other composites owing to the more mobility of polymer chain. Cole – cole plot showed that the structure of all the fabricated composites was heterogeneous in nature and kenaf fiber composite displayed the higher heterogeneity among all other materials. Moreover, the modeling of storage modulus and damping factor was performed and compared with the experimental results. The results showed good agreement with the theoretical and experimental values.

Density Measurement, Tensile and Morphology Properties of Polylactic Acid Biocomposites Foam Reinforced with Different Kenaf Filler Loading

This paper investigates the performance of polylactic acid (PLA)/kenaf fiber (KF) composites foamed using azodicarbonamide (AC) in terms of density, mechanical, and morphology aspects. The KF loading was varied in the range of 20-40 wt. %. The mixtures were compounded using a co-rotating twin-screw extruder and followed by hotcold pressing in order to prepare test specimens for characterization. The density of the foamed composites showed a fluctuate trend where it decreased at lower KF loading (0-20 wt. %) while further increasing fiber loading (30-40 wt. %) resulted in an increase of the composites density. Tensile results showed that the optimum loading of KF was achieved at 30 wt. % with an improvement of 135, 153, and 27.6% for stress at yield, strain at break and Young modulus, respectively, as compared to neat PLA foam. Field emission scanning electron microscope (FESEM) micrographs confirmed the fiber dispersion and morphological interaction between PLA and KF components.

Non-Isothermal Crystallization Kinetics of Poly(Lactic Acid)/Kenaf Fiber Composites

The non-isothermal crystallization behavior of poly(lactic acid) (PLA)/kenaf fiber (KF) composites was investigated using differential scanning calorimetry (DSC) at different cooling rates (1, 2.5, 5, and 7.5 °C/min) with various KF sizes from 25 to 300 µm. The modified Avrami, Ozawa, and Mo methods were applied to study the non-isothermal crystallization kinetics of neat PLA and PLA/KF composites. It was found that KF size of 80-106 µm acts as nucleating agent during non-isothermal crystallization of PLA/KF composites since the values of half-time of crystallization (t1/2) of PLA80 were the fastest as compared to neat PLA and other PLA/KF composites at a given cooling rate. The AvramiJeziorny crystallization rate constant (Zc ) increased upon increased of cooling rates for both neat PLA and PLA/KF composites indicating the improvement in crystallization. However, only the Zc values for PLA80 were faster than PLA/ KF composites but slower than neat PLA at a certain cooling rate. The Ozawa method did not apply satisfactorily for both neat PLA and PLA/KF composites. Meanwhile, the results showed that the Mo method can be successfully applied by providing a good fitting for all cooling rates of neat PLA and PLA/KF composites. The Kissinger activation energy (ΔE) of PLA80 recorded the lowest value indicating the size of KF between 80-106 µm accelerated the noncrystallization of PLA.

Fabrication of Automobile Component Using Hybrid Natural Fiber Reinforced Polymer Composite

ABSTRACT In recent years, natural fibers have been used more frequently for their lower weight to strength ratio, low cost, and environmental-friendly attributes. In this work, sisal/kenaf fiber reinforced with epoxy matrix hybrid composite (HC) was manufactured and their mechanical properties were compared with the sisal fiber composite (SFC) and kenaf fiber composite (KFC). Water absorption was carried out to find the moisture absorption capacity of the manufactured HC. HC provides better properties when compared with SFC and KFC. Hybrid composite is suitable for light weight automobile applications.

An Investigation of Kenaf Plant Fibers as Reinforcements in Interwoven Kenaf/Polyethylene Terephthalate (Pet)/Epoxy Hybrid Green Composites

Renewable materials have some bearing on the environment and have since increased research works related to polymer composites. This work was conducted to investigate the effects of interwoven kenaf fibers and the use of kenaf fibers in composites. In this research, interwoven between kenaf and polyethylene terephthalate (PET) was prepared and epoxy was used as the polymer matrix to form composites. The kenaf fiber composites with various kenaf fiber contents (2, 5, 8, and 10 wt %) interwoven with (PET) fibers were prepared by using open mould method. The properties of kenaf/PET/epoxy composites (KPTE) were studied. The kenaf fiber composites characterization was determined based on their mechanical properties, water absorption, morphology and thermal properties. The tensile strength test was performed using Testometric machine. The finding shows that the strength increases as the amount of kenaf fibers in the composites increases. The composites with 10% kenaf fibers interwoven PET displayed the highest tensile strength (85.3 ± 2.9 MPa) while unfilled epoxy show the lowest tensile strength (64.1 ± 16.5 MPa). The addition of kenaf fibers minimally increases the water absorption up to about 1.4%. The increases of kenaf fibers also reduces the overall thermal stability of the composites compared to the PET and epoxy resin composites. The morphology properties of KPTE composites support the tensile properties surface of the composites. This study assists to propose the kenaf fibers as a potential filler for properties improvements in epoxy-based composites contributing to the development of another environment-friendly material.

Mechanical Properties of Banana Fabric and Kenaf Fiber Reinforced Epoxy Composites: Effect of Treatment and Hybridization

Nowadays, Natural Fiber Reinforced composites (NFCs) are emerging to be a good substitute for synthetic fiber reinforced composites as NFCs have many advantages such as low density, high specific strength, recyclability, low cost and good sound abatement quality etc. Among all types of NFCs, a vast study has been done on banana fiber and kenaf fiber reinforced composite. However, only limited work has been done on the banana fabric, kenaf fiber reinforced composite and the effect of their hybridization on mechanical properties. In this paper, an attempt has been made to study the mechanical properties of the banana fabric, kenaf fiber and hybrid banana fabric/kenaf fiber reinforced composites. Effect of alkali treatment on kenaf fiber reinforced composite is discussed in the paper. For the present work, plain-woven banana fabric and randomly oriented kenaf fiber are used as reinforcement while the epoxy resin is used as a matrix. samples are fabricated using hand lay-up and vacuum bagging method. Curing is done at ambient temperature (250C-300C) for 48h. Tensile, impact and hardness test has been performed on a specimen according to ASTM standards. Improvement in mechanical properties is observed after alkali (6% NaOH) treatment on kenaf fiber reinforced composite. Tensile testing behavior of randomly oriented kenaf fiber composite has been studied using Finite element method and results are compared with experimental investigations. This topic present big potential because it seeks to find solution for sustainable development with environmental concerns.

Water Absorption and Flexural Property of Unidirectional Polypropylene/Sumberejo Kenaf Fiber Composites

Kenaf fiber can be used as an alternative to synthetic fiber reinforcement in composites. This research was conducted in order to determine the flexural and diffusion properties of the composite by varying the fiber fractions. Before being used as a reinforcement, kenaf fiber was firstly treated with alkali treatment in NaOH solution for 24 hours. Polypropylene and kenaf fibers were fabricated with a hot press machine. The fiber fractions were 30 wt%, 40 wt%, 50 wt%, and pure polypropylene samples were also fabricated as a comparison. The highest flexural strength, the minimum water absorption and water content were found in the polypropylene/30 wt% kenaf fibre composites with the value of (4.77 ± 0.799) MPa, (3.61 ± 0.823)% and (0.192 ± 0.154)% respectively.

The Impact Resistance, Flammability, and Hardness of Polypropylene/Unidirectional Sumberejo Kenaf Fiber Composites

The use of natural fibers to substitute synthetic fibers on composites has been an interest to be developed. Kenaf is a plant that abundant in Indonesia because it‘s adaptive and its fiber has good strength. The purpose of this study was to determine the value of impact resistance, flammability, and hardness of polypropylene / unidirectional Sumberejo kenaf fiber composite boards in accordance with Standar Nasional Indonesia (SNI). Composites were fabricated by the variation of fiber, which were 30 wt%, 40 wt%, and 50 wt%. Pure polypropylene samples were also fabricated for comparison. The fabrication used a compression molding method. The best results were obtained from polypropylene / 50 wt% kenaf fiber composites with impact energy, flammability, and hardness values were (47.54 + 10.7) J / cm2, (7.1±5.1) mm / minute, and (66 + 0.8) HD respectively. Optical microscope observation on the impacted surface was a destruction of the matrix-fiber bonding and fiber breakage, in which showed the energy of impact was absorbed by kenaf fiber. The observation on the burned surface was burnt kenaf fibers and rest of PP that bonding with kenaf fiber, this indicated the kenaf fiber acted as an oxygen barrier.

Komposit Gentian Kenaf: Satu Ulasan bagi Sintetik dan Biodegradasi Polimer Matrik

This review paper deals with the previous and current works published on the kenaf fiber composites. Kenaf is grown commercially in South East Asia country and widely used in the construction and infrastructure as well as in the automotive industry. Kenaf fiber is usually reinforced with synthetic based polymer resin such as polypropylene. However, recent studies tend to concern towards the environmental issues which kenaf fiber act as an alternative natural fiber competitor. Moreover, the combination of the natural fiber and the biodegradable polymer able to reduce the negative impact on human health. Hence, researcher-initiated the interest focusing on the biodegradable materials obtained from the renewable sources. A huge attention gave to the kenaf fiber reinforced bio-polymer materials such as polylactic acid. The processing technique and the fiber orientation within the composite materials are discussed extensively in order to obtain the maximum composite performance. Results indicated that the mechanical properties; tensile strength and tensile modulus, are improved as the kenaf fiber was aligned in uni-direction. Therefore, this paper overview on the kenaf retting types in the common form of kenaf fibers and discussing the thermoplastic polymer matrices types used in the fabrication processes. In addition, the challenging of using kenaf fibers composites and its application in the automotive industry also highlighted.

Effect of processing temperature and foaming agent loading on properties of polylactic acid/kenaf fiber composite foam

The focus of this study was to investigate the effect of processing temperature and foaming agent loading on physical and mechanical properties of the foamed polylactic acid (PLA)/kenaf fiber (KF) composites. The foamed polymer composites made from PLA, KF and azodicarbonamide (ADC) were prepared via extrusion and compression molding. The temperature profile used for extrusion was set at 170, 185, 180, 175˚C (high temperature profile) and 165, 170, 175, 160˚C (low temperature profile). ADC loadings were varied at 0, 1, 3 and 5 phr. The density of the foamed composites exhibited a decreasing trend with the increasing of ADC loading. The morphology was analysed by Field Emission Scanning Electron Microscope (FESEM) and the results revealed the bigger size in the PLA/KF foamed composites extruded with high temperature. Tensile strength, strain @ break and Young modulus of the foamed composites decreased accordingly with respect of foaming agent content. The mechanical strength was positively affected when the lower extrusion temperature was used for extrusion.

Kenaf Reinforced PLA Composite Thermoforming: A Numerical Simulation

Recent manufacturing development focuses on the optimum technique of product fabrication that time-consuming and cost-effective including thermoforming process. Fundamental studies on the thermoforming process, especially in the uni-directional direction of kenaf fiber composite are still in preliminary stages. Hence, a numerical simulation is performed in order to minimize the experimental conduct. PAM-FORM software is used for modeling and simulation of the thermoforming process by studying the effect of processing parameters on the results of the simulation. The optimum thermoforming process parameter in terms of temperature, puncher speed, puncher radius and composite thickness are determined by the design of experiments. The output parameters including thinning of the composite, shear angle and stress are analyzed to identify the wrinkling defects which further analyzed using the Design-Expert software. Results demonstrate that at a temperature of 120 °C, puncher speed of 28.78 m/s, puncher radius and composite thickness of 4 mm and 2 mm, respectively able to achieve minimum thinning and minimal shear angle during the thermoforming process.

Mechanical properties of kenaf fiber thermoplastic polyurethane-natural rubber composites

Thermoplastic polyurethane-natural rubber TPUR-NR composites filled with treated and untreated kenaf fiber as filler were prepared at different TPUR and NR contents. The content of kenaf fiber was maintained at 12.5 wt % and the fiber was treated with 6 % solution of sodium hydroxide (NaOH), then dried for 24 hours in 100 °C, hot blended with polymer components, pulverized and pressed. The mechanical properties of the composites such as tensile, flexural and impact strength were determined, and their dependence on NaOH treatment of kenaf fibers was investigated. The analysis using scanning electron microscope (SEM) was implemented to identify the effect of alkali treatment on the microstructure of kenaf fiber and TPUR-NR composites. An improvement of fiber surface roughness and bonding between the fiber and polymer as well as an increase in impact energy and elongation at break of the composites was observed.

Mechanical properties and biodegradability of enzyme-retted kenaf fiber composites

The mechanical properties and biodegradability of retted kenaf and modified starch composites fabricated by adding enzyme-retted kenaf as a filler and poly(vinyl alcohol) (PVA), poly(ethylene glycol), or glycerol as a plasticizer are compared with those of the NaOH-retted counterparts fabricated under identical conditions. In the case of enzyme retting, the composite treated with the PVA plasticizer was deemed the most appropriate for achieving optimal tensile strength, flexural strength, and flexural modulus. Further, the retting treatment, the length of the kenaf fiber, the type of treatment (single- or double-sided), and the adhesion force at the interface significantly affect the mechanical properties of the composites. According to the aerobic biodegradability assessment in natural reclamation conditions, the modified starch composite fabricated using 50-mm-long enzyme-retted kenaf fibers as the filler and double-side treated with PVA plasticizer showed a biodegradation rate of 80% or higher after 80 days.

Effect of Fiber Loadings and Treatment on Dynamic Mechanical, Thermal and Flammability Properties of Pineapple Leaf Fiber and Kenaf Phenolic Composites

This study deals with the analysis of dynamic mechanical, thermal and flammability properties of treated and untreated pineapple leaf fiber (PALF) and kenaf fiber (KF) phenolic composites. Results indicated that storage modulus was decreased for all composites with increases in temperature and pattern of slopes for all composites, having almost the same values of E' at glass transition temperature (Tg). The peak of the loss modulus of pure phenolic composites was shown to be much less. After the addition of kenaf/PALF, peaks were higher and shifted towards a high temperature. The Tan delta peak height was low for pure phenolic composites and maximum for 60% PALF phenolic composites. Cole-Cole analysis was carried out to understand the phase behavior of the composite samples. Thermogravimetric analysis (TGA) results indicated that pure phenolic composites have better thermal stability than PALF and kenaf phenolic composites. Vertical and horizontal UL-94 tests were conducted and showed pure phenolic resin is highly fire resistant. The overall results showed that treated KF composites enhanced the dynamic mechanical and thermal properties among all PALF/KF composites.