Natural Fiber Composites Research Articles

Structural health monitoring of natural fiber‐based hybrid composites

AbstractThe purpose of this article is to evaluate mechanical behavior, detect early damage, and understand failure mechanisms of natural fiber composites using acoustic emission testing (AE). Natural fiber composites are increasingly used in various applications due to their low cost, renewable and biodegradable nature, and excellent mechanical properties. However, their mechanical behavior and failure mechanisms are complex and must be better understood, and nondestructive testing methods are required to evaluate their performance. The article discusses the AE behavior of banana‐ramie‐epoxy composites in tensile tests for the first time. The composites were fabricated by compression molding with 4‐layer banana‐ramie epoxy at 0° stacking. The AE signals were recorded and analyzed during the test using a piezoelectric high‐frequency sensor to identify the different types of AE events. The results showed that the composites exhibited high levels of AE activity at different stages. AE signals were closely related to the damage mechanisms occurring in the composites, such as fiber/matrix debonding, fiber breakage, and matrix cracking. This research results also suggest that AE can help optimize the design and performance of novel composites in practical applications.

Ecosystem sustainability and conservation of waste natural fiber strengthen epoxy composites for lightweight applications

AbstractIn recent days, the automobile, aerospace, and marine sectors are imposed to search the similar quality alternative material with desired mechanical and wear characteristics obtained by using natural fiber extracted from environmental wastes. The current investigational characteristics study focuses to increase the mechanical properties of composite by using NaOH‐treated natural fiber like jute and sisal bonded with epoxy resin via the wet filament technique. The four different positions of fibers like the jute‐sisal fiber were dipped with epoxy resin and waved as random (multi‐directional), 0° (unidirectional), 90° (bi‐directional), and interlock position. The developed natural fiber composites were subjected to tensile, impact, and flexural strength made by ASTM procedure. The composite prepared with interlock position showed higher tensile, impact, and flexural strength 49.51 ± 1.51 MPa, 12 ± 0.98 J, and 57.31 ± 1.98 MPa respectively and improved by 12%, 33.3%, and 10% as compared to random (multi‐directional) composite. So the developed composites were enhanced by the conservation of jute/sisal fiber bonded with epoxy as interlocking distribution is utilized for lightweight applications and the conservation of waste natural fiber retained the ecosystem sustainability.

Development of biomass adhesives based on aminated cellulose and oxidized sucrose reinforced with epoxy functionalized wood interface

Both increasing environmental issues and the lack of fossil resources have increased the importance of wood-based natural fiber composites. Therefore, high performance, sustainable, and environmentally-friendly bio-based wood adhesives are highly desirable. We developed a new biomass adhesive based on aminated cellulose (AC) and oxidized sucrose (OS), and reinforced it with an activated wood interface to improve its bonding performance. To this end, the natural wood interface (NWI) was customized with an epoxy group to produce the epoxy-functionalized wood interface (EFWI), one end of which is tethered to the wood surface. The epoxy group at the other end reacts with the amino group of AC, resulting in hydrophobicity and forming new covalent bonds in the adhesive layer, such as -Si-O-Si-, -Si-O-C-, -C-N-C-, and -O-C-C- bonds. Characterization of the adhesive interface is realized by FTIR, 13C NMR, XPS, XRD, and SEM. Dry and wet shear strengths are also investigated by tensile shear strength measurements in China National Standards (GB/T 9846-2015). Results show that OS-AC adhesives have better dry and wet shear strengths at EFWI in comparison with those on NWI, reaching 2.52 and 1.48 MPa, respectively. Thus, the construction of a functionalized wood adhesive interface dramatically enhances the bonding strength and water resistance of biomass adhesives. This study provides new insights for developing renewable, low cost, and green bio-based wood adhesives by chemical modification of the wood interface.

Development of hybrid composite with natural fillers for mechanical property and machinability study

The urge to build a more environmentally friendly future has motivated researchers to examine composites outside of synthetic fiber and continue to consider natural fibre polymer composite. This present research, the hybrid bio composite was developed by bio fillers and natural fibres. The preliminary investigation was done to examine the possibility of using natural fillers (palm and coconut shell) in natural fibre (hemp and basalt) reinforced polymer (NFRP) composite for manufacturing application. In that way initially mechanical (tensile and flexural) properties testing were done on four different combinations of NFRP by using palm and coconut shell particles, to their influence on mechanical properties (tensile stress 278 MPa and flexural stress 330 MPa). It was found that 5% wt. palm + coco shell fillers combination hybrid composite presented good results in mechanical properties. Then 5% wt. palm + coco fillers was added in the matrix phase of NFRP composite was developed and study the machinability properties by using Abrasive Water Jet Machining (AWJM). NFRP machining in the relationships of material removal rate (MRR), kerf angle and surface roughness has been experimentally examined for various process parameters (nozzle pressure, distance stand and transverse speed). The research values for quality properties (MRR, Kt and Ra) were analysis-based on the trimming factors by developing the Taguchi method. The influence of optimized input process parameters on quality features were examined by utilizing experiential models. From this study, it is noticeable that, filler material in natural fiber composites reduces the kerf angle and the low and very high traverse speed leads the wide disparity in kerf inclination. For obtaining the good surface roughness and material removal rate medium traverse speed and medium stand of distance is the significant parameter respectively and moreover impact of jet pressure on surface finish is 3 times lower than the impact supplied to the surface finish by traverse speed

Additive manufactured acoustic absorbers made of wood-fiber composites with modified infill patterns

ABSTRACT The rapid urbanization and economic expansion have increased the negative consequences of environmental noise pollution. The sound that originates from various sources comes from distinct spectrums. To address the aforementioned issue, acoustic absorbers were 3D printed with varying infill patterns to absorb sound across a wide range of frequencies. Acoustic absorbers made of polylactic acid/polyhydroxyalkanoates-wood fibers (PLA/PHA-WF) were fabricated using Fused Deposition Modelling (FDM) technology, and their physical, mechanical, water absorption, biodegradation, and acoustic characteristics were measured and discussed. Acoustic absorbers printed with different infill patterns have a slight difference in density due to the size of the pores and the contact sites exhibited by the infill pattern. As a result, acoustic absorbers printed with varying infill patterns allow sound waves to enter and absorb sound at distinct spectrum levels. Modifying the infill pattern also had an effect on mechanical, water absorption, and biodegradation properties with minor deviations. The proposed biodegradable acoustic absorbers made of natural fiber composites and manufactured by FDM can be installed on building walls or roofs depending on the required acoustic absorption spectrum.

Biodegradable Poly(butylene adipate-co-terephthalate) Nanocomposites Reinforced with In Situ Fibrillated Nanocelluloses

The enhancement of mechanical properties is highly required for the expanded applications of biodegradable polymers like poly(butylene adipate-co-terephthalate) (PBAT). The use of nanocellulose as reinforcing fillers is one of the effective approaches while preserving the biodegradability of polymers, but the dispersion of nanofibers in polymer matrixes is a great challenge. Here, we report an in situ fibrillation method to prepare nanocellulose-reinforced PBAT composite films with superior mechanical properties and enhanced degradability while promoting the easy dispersion of natural plant fibers in the polymer matrix, which overcome the limitation of natural fiber composites for thin film applications. A hemicellulose-rich holocellulose fiber was selected and silanized prior to melt compounding with PBAT, in which in situ fibrillation of fibers and the dispersion of in situ fibrillated cellulose nanofibrils (CNFs) occurred simultaneously. The nanostructure, mechanical properties, and degradability of the resulting composite films were characterized. Compared with pristine PBAT, the incorporation of 1 wt % CNF fillers increased the tensile modulus by 82% while possessing a tensile strength of 26 MPa, an elongation of 372%, and a toughness of 75 MJ/m3, surpassing most reported data. Moreover, the degradability of PBAT was enhanced as well. Altogether, this study paves a new way of making biodegradable nanocomposites, which expand the application areas, especially where films are required.

A comprehensive review on the use of natural fibers in cement/geopolymer concrete: A step towards sustainability

The construction industry is shifting towards environmentally friendly products due to the rising demand for non-renewable raw materials, their high energy consumption, and, most importantly, their detrimental environmental effects. High levels of solid waste produced by raw materials release dangerous gases like nitrous and Sulphur oxides, which are very harmful to the environment. In recent years, the usage of fibers has tremendously increased to make significantly robust structures. For sustainable, waste-free development, manufactured fibers can be replaced with natural fibers without compromising on the requirements. This study considers various natural fibers like basalt, coconut/coir, banana, sugarcane bagasse, hemp, kenaf, bamboo, jute, sisal, abaca, and cotton, and their effects on fresh and hardened concrete have been discussed. This article also reviews the composition, preparation, and processing procedures of various natural fibers, and their potential applications in building materials are highlighted. Future research avenues are identified, and possible negative impacts and limitations are discussed. Our findings confirm the feasibility of standard concrete using natural fibers in cement or geopolymer concrete. Lastly, this review compiles insights from numerous sources to aid academia and the construction industry in developing eco-friendly materials.

Comparative Study of Chemically Treated Sugarcane and Kevlar Fiber to Develop Brake Resistance Composites.

Recently, much research has revealed the increasing importance of natural fiber in modern applications. Natural fibers are used in many vital sectors like medicine, aerospace and agriculture. The cause of increasing the application of natural fiber in different fields is its eco-friendly behavior and excellent mechanical properties. The study's primary goal is to increase the usage of environmentally friendly materials. The existing materials used in brake pads are detrimental to humans and the environment. Natural fiber composites have recently been studied and effectively employed in brake pads. However, there has yet to be a comparison investigation of natural fiber and Kevlar-based brake pad composites. Sugarcane, a natural fabric, is employed in the present study to substitute trendy materials like Kevlar and asbestos. The brake pads have been developed with 5-20 wt.% SCF and 5-10 wt.% Kevlar fiber (KF) to make the comparative study. SCF compounds at 5 wt.% outperformed the entire NF composite in coefficient of friction (µ), (%) fade and wear. However, the values of mechanical properties were found to be almost identical. Although it has been observed that, with an increase in the proportion of SCF, the performance also increased in terms of recovery. The thermal stability and wear rate are maximum for 20 wt.% SCF and 10 wt.% KF composites. The comparative study indicated that the Kevlar-based brake pad specimens provide superior outcomes compared to the SCF composite for fade (%), wear performance and coefficient of friction (Δμ). Finally, the worn composite surfaces were examined using a scanning electron microscopy technique to investigate probable wear mechanisms and to comprehend the nature of the generated contact patches/plateaus, which is critical for determining the tribological behavior of the composites.

A review of fused filament fabrication of continuous natural fiber reinforced thermoplastic composites: Techniques and materials

AbstractThe combination of continuous natural fiber and fused filament fabrication (FFF) 3D printing enables the manufacturing of low carbon emitting, environment friendly, lightweight, and high strength biomass composites with designated geometry characteristics. In current literature, reviews associated with continuous fiber 3D printing primarily cover synthetic fibers, such as carbon fiber, Kevlar, and glass fiber. Very few pieces of literature on the FFF printing of continuous natural fibers are available. Techniques/methodologies for incorporating continuous natural fiber reinforcements in FFF is an emerging field of research. A comprehensive review and discussion on current progress and the future prospects of continuous natural fiber 3D printing would be beneficial to its development. This article summarizes the current research status of continuous natural fiber 3D printing, including information on printing techniques, materials, and the influence of printing parameters on composite properties, so as to provide reference for the future development of FFF technology using continuous natural fiber and thermoplastic composites.

Thermal and dynamic performance of kenaf/washingtonia fibre-based hybrid composites

The application of hybrid natural fibres incorporated with bio phenolic composites is significant due to their sustainability and low-cost rates. In this paper, two natural fibres composites were prepared using a hand lay-up technique. The thermal stability, dynamic-mechanical, and thermo-mechanical characterisations of kenaf fibre (KF)/Washingtonia Leaf Stalk Fibres (AW)/epoxy biocomposite were investigated in this paper. Thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA), respectively, were used to examine the thermal stability and the coefficient of thermal expansion (CTE) and the dynamic mechanical properties of composites, respectively. The Thermogravimetric (TG) analyses showed that the addition of KF and AW enhanced the thermal stability of the epoxy composites. 7AW/3KENAF showed the most significant improvement in thermal stability (Tonset; 284.52 °C and Tmax; 368.25. Furthermore, the hybrid biocomposite exhibited the highest storage modulus (2668.9 MPa) among all other pure and hybrid biocomposites. On the other hand, the TMA findings illustrated that the 50% AW sample exhibited the highest value of CTE (242 μm/m °C) at the maximum temperature (175 °C) among all samples. Briefly, it is obvious that the combination of WA with KENAF enhanced the potential in improving thermal, dimensional and dynamic mechanical characterisations of epoxy composites and can be utilised in building applications that dictate elevated dimensional stability. It was proven that the hybrid biocomposites prepared in this work supported by hybrid natural fibres as strengthened bio fillers might benefit the performance of epoxy composites, which could broaden the application range of industrial and engineering applications and provide novel ways for its effective uses.

Mechanical characterization and corrosive impacts of natural fiber reinforced composites: An experimental and numerical approach

The long-term durability and environmental degradation of the mechanical properties of natural fiber composites are very important in corrosive or humid environments. Therefore, the change in mechanical properties between the normal and corrosive environments was the key parameter for this study. The natural reinforcements were mainly unidirectional jute and banana fiber here. Glass fiber mats and aluminum foil were also used in one case each. Various types of composites were fabricated using different combinations. Multiple studies have examined the mechanical properties. Among those, the tensile and flexural strengths were examined both pre-post immersion in seawater for sixty days until saturation. The matrix began to erode, and micro cracks formed, resulting in a loss of mechanical strength. In addition, a water absorption characteristics curve with a coefficient of diffusion was determined. The tensile and flexural results were verified by finite element analysis. SEM micrographs enabled the identification of the weakening of the fiber/matrix interface induced by water ageing.

Characterisation of mechanical and thermal properties of copper slag filled composite material with and without coconut fibre

Natural fibre composites are receiving considerable attention as a substitute for many conventional materials, such as plastics, in industrial applications. Especially in countries like India, the rich supply of coconuts makes it a sustainable source of natural fibre to be used for composite manufacturing. Conventional material alone is not enough to meet the diverse requirements of design engineers. Copper slag, a by-product of copper production, contains materials like iron, alumina, etc. Dumping or disposal of such huge quantities of slag causes serious environmental problems. By appropriate usage of slag physical and mechanical properties of the materials can be enhanced. The objective of the present work is broadly classified into two. Firstly, use copper slag as particulate filler material for the epoxy matrix composites and to study the effect on the thermal and mechanical properties of reinforced composite material. Secondly, to prepare coconut fibre reinforced with epoxy resin with copper slag as filler material and to analyse the changes observed in the properties of the composite material. Lastly, the properties are compared with that of gypsum wallboard and aluminium composite panel to check the compatibility of the developed natural fibre composite as a possible replacement for sealing purposes.

Studi Pengaruh Perlakuan KOH Terhadap Kekuatan Tarik Komposit Serat Rami

Currently, natural fiber composites have become the main choice for several industrial applications in the world. The strength of natural fibers such as hemp is based on laboratory results of mechanical strength testing which show that hemp has very suitable properties as a reinforcing composite for prosthetic socket materials. The tensile test is a mechanical stress-strain test that aims to determine the strength of a material against tensile forces. In the test, the test material is pulled until it breaks. Tensile testing is carried out to look for stress and strain (stress-strain test). From this test, we can know some of the mechanical properties of materials that are needed in engineering design. The results of research conducted on the study of the effect of KOH treatment on the tensile strength of hemp fiber composites show three things. First, the highest tensile stress value in hemp fiber was found in the 2% KOH treatment with a long soaking time of 2 hours with a value of 25.3 MPa. Second, the lowest tensile strain value in hemp fiber was found in the 6% KOH treatment with a long soaking time of 2 hours with a value of 0.1%. Third, the highest modulus of elasticity in hemp fiber was found in 6% KOH treatment with a 1-hour soaking time with a value of 47.1 MPa

Genetic Algorithms: A Solution to Fiber Reinforced Composite Drilling Challenges

Natural fiber composites are a group of materials that have gained increasing attention in recent years due to their potential to replace traditional materials in various applications. However composite materials are made up of layers of fibers and resin that can separate from each other during drilling, leading to delamination. This paper proposes a multi-objective optimization approach for drilling natural fiber composites, considering three key drilling parameters: cutting speed, feed rate and tool geometry. The objective is to minimize delamination and thrust force. Multiple linear regression analysis is employed to develop the regression equations for each objective function, which are then optimized simultaneously using a multi-objective genetic algorithm (MOGA). The results demonstrate that the proposed approach can effectively identify the optimal drilling parameters that balance the trade-offs between the competing objectives. The proposed approach can be useful for improving the efficiency and quality of drilling natural fiber composites, which are increasingly used in various industrial applications.

Drilling of banana stem fibers and polyurethane derived from castor oil composite

Natural fibers composites obtained from waste of agricultural processes appear as an alternative to materials from non-renewable sources. Drilling these composites is challenging due to the non-homogeneous structure and behavior of the natural fibers and the polymeric matrix. This work uses different drill types and machining parameters to investigate the drilling process in a composite with banana stem fibers and polyurethane derived from castor oil. Hole damages, thrust force, torque and chip morphology were evaluated. The best results were found using a twist drill at 19 m/min cutting speed and 0.1 mm/rev feed rate. Drill type was the main factor in generating damage in the holes, while torque and thrust force were less influential.

Experimental, Theoretical, and Numerical Analysis of Laminated Composite Prosthetic Socket Reinforced with Flax and Cotton Fibers

A lot of work has been done to enhance the mechanical properties of natural fiber composites to increase their strength and applicability. This research aims to investigate the utilization of natural fibers for below-knee prosthesis socket manufacture using the vacuum bagging technique experimentally, theoretically, and numerically. Lamination groups of different layering arrangements were evaluated by tensile tests. The finite element methodology (FEM) was utilized by noting the dispersion of safety factors, equivalent Von-Mises stress, and total deformation, while the theoretical part estimated Poisson's ratio, volume fraction, failure index, and theoretical safety factor. The study found that the number and type of fibers affected mechanical properties, in addition, that combining natural and artificial reinforcements permits the creation of high-performance bio-composites. FEM results coincided with both the theoretical and experimental results, with lamination 9 having the highest modulus of elasticity (5.6 GPa) and tensile strength (423 MPa). This work uncovered the properties of the proposed hybrid fiber-reinforced composites that haven't been exasperated up to the present and showed that sockets can be assembled from sustainable, low-risk materials without sacrificing the composite materials' strength. The study found that bio-composites with better performance could be created by combining synthetic with natural reinforcements.

Wear properties of natural fiber based composites – A brief review

AbstractNatural fiber composites' appealing properties have enabled their use in a wide range of engineering applications, including automotive and structural applications. Wear is a common issue in automotive and structural applications, increasing the likelihood of material failure. As a result, composites with increased wear resistance are required. Natural fiber composites have completely different wear properties than metals. Understanding the wear mechanism of natural fiber composites is critical for their potential use in a variety of applications. Wear is of different types, each with its own mechanism of material loss. Wear is determined by material properties, such as matrix and reinforcement properties. The critical factors influencing the wear performance of natural fiber composites are fiber loading, fiber orientation, fiber length, and fiber interface. This review attempted to investigate the different types of wear in fiber composites and their impact on natural fiber composites. This article could serve as a one‐stop shop for learning about the wear characteristics of natural fiber composites.

Uncertainty analysis for prediction of elastic properties of unidirectional bamboo fiber-reinforced composites

This paper presents a virtual framework to obtain the elastic response of unidirectional (UD) continuous bamboo fiber-reinforced composites based on the micromechanical modeling approach. The virtual framework involves the development of an algorithm for the generation of stochastic Representative Volume Elements (RVEs), taking into account the micro-structural uncertainty and variability of the bio-based bamboo fibers and their composites. The developed algorithm and model are validated with experimental characterizations and theoretical models. Different statistical micro-structural realizations with random fiber packing, fiber geometries, and variable RVE sizes are compared to investigate the effects of these parameters on the accuracy of the prediction of the elastic properties of bamboo fiber-reinforced composites. All models and loading scenarios are applied automatically through Python scripting in the Abaqus finite element (FE) solver. The uncertainty analysis of input parameters is carried out through parametric studies. This virtual micromechanical framework can be further linked in the future to macroscale models of bamboo or other natural fiber composites for multiscale prediction of the behavior of biocomposite structures under in-service loading.

An Overview of Natural Fiber Composites for Marine Applications

Environmental emergency awareness has been gaining momentum in recent years in the composite manufacturing industry, with a new generation of composite materials minimizing their harmful environmental impacts by employing more sustainable manufacturing processes and, where possible, replacing synthetic materials with more sustainable bio-based materials, thus more efficiently using energy and material resources. In this context, natural fiber composites are proposed as appealing candidates to replace or reduce the use of synthetic fibers for reinforcing polymers in several industrial fields, such as the marine sector, where composite usage has been extensively studied in recent years. This review aims to present a thorough overview of the usage of natural fiber composites for marine applications, discussing the most relevant criteria required for applications where water exposure is expected. For this purpose, the review outlines the natural fibers and matrices used, analyzes the resultant composites’ mechanical properties, and presents the fiber treatments required before manufacturing, as well as the main manufacturing processes adopted for natural fiber composite production. The advantages and disadvantages of natural fibers compared to synthetic fibers are also presented, including economic and environmental credentials. Finally, a list of marine components with natural fiber reinforcements developed in recent years is reported.

Effect of graphene oxide fibre surface modification on low-velocity impact and fatigue performance of flax fibre reinforced composites

Fatigue and impact resistance are essential performance indicators in structural biocomposites. Integrating multilayer and oxygen-rich graphene oxide (GO) crystals as a fibre surface modification or reinforcing agent in polymer matrix systems have been shown to enhance the interfacial strength and toughness of natural fibre composites. However, the state-of-the-art literature on the GO-modification of composites has focused mainly on their microscale and quasi-static mechanical performance. Here, the fatigue testing results showed that surface modification of flax fibres with GO reduces the slope of the S-N curve by 17% and promotes fibre pull-outs upon failure. Based on the in-situ impact damage analysis, the GO-modification delayed the impact damage initiation and prolonged the stable damage progression phase. The impact perforation energy was similar for modified and unmodified specimens. At kinetic energies below the perforation limit, the GO-modification suppressed the extent of fibre failure and endowed flax-epoxy specimens with better damping performance.