Properties Of Natural Fiber Reinforced Composites Research Articles

A Review of Natural Fiber-Reinforced Composites for Lower-Limb Prosthetic Designs.

This paper presents a comprehensive review of natural fiber-reinforced composites (NFRCs) for lower-limb prosthetic designs. It covers the characteristics, types, and properties of natural fiber-reinforced composites as well as their advantages and drawbacks in prosthetic designs. This review also discusses successful prosthetic designs that incorporate NFRCs and the factors that make them effective. Additionally, this study explores the use of computational biomechanical models to evaluate the effectiveness of prosthetic devices and the key factors that are considered. Overall, this document provides a valuable resource for anyone interested in using NFRCs for lower-limb prosthetic designs.

Hygrothermal coupled modeling and behavior analysis of natural fiber-reinforced tubular composites

The mechanical properties of natural fiber-reinforced composites (NFRCs) are susceptible to the coupled effect between environmental temperature and humidity. However, the coupled system for the heat and moisture field in NFRCs remains unclear. In regard to this, this paper presents hygrothermal coupled modeling of natural fiber-reinforced tubular composites (NFRTCs), considering the correlation between natural fiber aggregation, matrix contents, and porosity. The transient hygrothermal field and distribution in NFRTCs are predicted using the differential quadrature method. The predicted results are verified by the comparison with the experimental data in the literature. Through the proposed model, the effect of hygrothermal coupling, boundary conditions, fiber aggregation, porosity, and structural dimensions on the hygrothermal responses and distributions are analyzed in detail. The results show that temperature and moisture fields decrease significantly when the hygrothermal coupling or the hygrothermal convection boundary condition is used. In addition, hygrothermal field distributions gradually decline with the increasing fiber weight fraction, outer-to-inner radius ratio, and porosity coefficient, as well as the smaller fiber aggregation parameter. These results can serve as a guideline for the design and manufacturing of reliable NFRTCs subjected to hygrothermal environments.

Effect of fiber treatment on physical and mechanical properties of natural fiber-reinforced composites: A review

Abstract Due to environmental and financial concerns, there is a growing demand for composite materials in a wide range of industries, including construction and automotive industries. In 2020, the market for wood plastic composites was estimated to be worth $5.4 billion. By 2030, it is expected to have grown to $12.6 billion, with a compound annual growth rate of 8.9% between 2021 and 2030. The fundamental disadvantage of reinforced composites by natural fibers is the different nature of the hydrophilic lignocellulosic and the hydrophobic thermoplastic polymers, although natural fibers would lower total costs. These composites typically fail mechanically as a result of fiber debonding, breaking, and pull-out. In a fiber-reinforced composite, the matrix’s function could be described as distributing the force to the added fibers using interfacial shear stresses. A strong connection between the polymeric matrix and the fibers is necessary for this procedure. Weak adhesion at the interface prevents the composite from being used to its maximum potential and leaves it open to attacks from the environment that could damage it and shorten its lifespan. Poor mechanical performance is caused by insufficient adhesion between hydrophobic polymers and hydrophilic fibers in natural fiber-reinforced polymer composites. Consequently, during the past 20 years, a variety of chemical, thermal, and physical methods have been employed to address these issues. These methods largely concentrated on the grafting of chemical groups that could enhance the interfacial contacts between the matrix and natural fibers. This review article aimed to give information on several types of fiber treatments and natural fiber-treated composites with a specific focus on their physical and mechanical properties.

A critical review of different properties of natural fibre-reinforced composites

The eco-friendly and sustainable nature of bio-based fibres has received much interest from analysts to incorporate them into the polymer matrix. The research of filled plastic composites has sparked much attention in the recent decade as a way to address the lack of petroleum resources. The use of plastic has been prominent in almost everything, from ordinary things to complicated structures and industrial parts. Natural fibres entice researchers and scientists want to use their qualities by reinforcing them with polymers. Fibre loading percentage, size and orientation of fibres, stacking sequences, degree of interfacial adhesion, fibre surface treatments, hybridization, and integration of fillers and coupling agents all influence the qualities of natural fibre-reinforced polymer composites. The article summarizes different chemical remedies affecting natural fibres to enhance their qualities. Effects on water absorption and tribological behaviour caused by chemical therapies were included in this study. As a result, the natural fibre-reinforced composites’ mechanical characteristics have also been discussed in the present study.

Influence of moisture absorption on tensile and compressive properties of natural fiber-reinforced thermoplastic composites

ABSTRACT The present research is aimed at examining the changes in tensile and compressive properties of natural fiber-reinforced composites (NFRC) exposed to various humidity conditions; this is due to the fact that moisture content (MC) in fibers is generally assumed to be detrimental to composite performance. It was found that once moisture is exposed, compressive strength and strain of specimens would be higher than those of tensile, whereas modulus of elasticity would be lower. Due to increasing moisture content, although elongation in all tests was enhanced, tensile and compressive strength declined by 15% and modulus of elasticity decreased by 20%. In addition, Poisson’s ratio for both compressive and tensile properties was nearly identical (0.33) in distinct moisture content. A new understanding of moisture’s effects on mechanical behavior is presented in this study by finding an optimum point for exposing moisture to increase compressive and tensile strength.

Physical, Mechanical, and Thermal Properties of Natural Fiber-Reinforced Epoxy Composites for Construction and Automotive Applications

Industrialization and population growth have significantly increased the demand for lightweight, high-strength materials for construction and automotive applications, ultimately increasing the demand for eco-friendly materials. Due to its environmental acceptability, technological feasibility, and economic viability, natural fiber-reinforced composite exhibits many potential engineering applications. However, the production and recycling of natural fibers are expensive. Researchers are now comparing natural fiber-reinforced composites with synthetic composites to determine the best materials, especially for construction and automotive engineering applications. This review paper focuses on natural fiber reinforced epoxy composites’ physical, mechanical, and thermal characteristics. These properties are critical for the effective design and use of composite materials such as construction and automotive applications. This review begins with a background of epoxy and natural fibers. The physical and chemical treatment for natural fiber composites to improve their properties is also briefly discussed, along with the critical factors affecting the physical, mechanical, and thermal properties of natural fiber-reinforced composites. Finally, concluding remarks and suggestions for future works are given.

Synergy of waste plastics and natural fibers as sustainable composites for structural applications concerning circular economy.

The increasing demand for shelters, depleting natural resources, concern for plastic waste, and rising awareness for the environment have attracted the contemporary world towards the recycling of waste plastics for the development of an alternative and sustainable building construction material. The plastics suffer due to their poor strength which can be successfully overcome by the reinforcement of natural fibers. The work aimed to develop and investigate the properties of natural fiber-reinforced composites for structural applications such as floor tiles and pavements. The composites were developed by utilizing three different types of waste plastics, namely, low-density polyethylene, high-density polyethylene, and polypropylene with the reinforcement of coconut (cocos nucifera) and Tossa jute (corchorus olitorius) fibers. The evaluation of the density, water absorption, compressive strength, and flexural strength was performed. Moreover, three-body abrasive wear performance was investigated under the conditions of different loads and sliding speeds. The wear mechanism was explored by the morphological analyses of the fractured and worn-out surfaces. The composite HDPE80C20 showed a maximum density of 1.603 g/cm3 and minimum percentage of water absorption to 0.2022. Moreover, the composite attained a maximum compressive and flexural strength of 40.10 and 10.04 (MPa), respectively. The ranges for abrasive wear were found to be 0.002375-0.20015 (cm3) and 0.01987-0.39593 (cm3) under the considered conditions of loads and sliding speeds, respectively. The comparative analysis of the properties suggested the reinforcement of 20 wt% of jute fiber with 80 wt% of high-density polyethylene for the development of composites for structural applications. The study highlighted the potential of waste plastics and natural fibers as value-added products for building construction with relevancy from socio-eco and environmental points of view.

Influence of Chemical Treatment of Natural Fibres Using the SPSS Method

Chemical Treatments of Natural Fibre Chemical treatment of hazardous waste involves converting it into non-toxic gases by changing or altering its chemical characteristics. Various treatment methods are used, such as reducing solubility or acidity through neutralization or pH adjustment, precipitation or oxidation and reduction, hydrolysis and photosynthesis, chemical oxidation (such as ozonation, electrolytic oxidation, and hydrogen peroxide), and chemical removal (such as alkali metal dichlorine and alkali). Commonly used chemical treatment processes include metallization, activated chemical treatment processes, chemical precipitation, neutralization absorption, disinfection (using chlorine, ozone, UV light), and ion exchange. Natural fibers obtained from the plant kingdom include cotton, flax, jute, bamboo, sisal, and co-conut husks. Cotton and flax are examples of seed hairs, while jute is an example of stem (or bast) fibers. Sisal is an example of leaf fibers. Animal fibers include secretions such as wool, hair, and silk. Popular animal fibers include angora and mohair. This paper reviews various chemical properties of natural fiber-reinforced composites, including changes resulting from the use of natural fibers. Chemical treatments, such as alkali, silane, acetylation, benzoylation, acrylation, malate coupling agents, isocyanates, permanganate, and others are discussed in relation to their effect on the fiber surface. The aim of these treatments is to improve adhe-sion between the fiber and polymer matrix. As a result, water absorption of composites decreases and their mechanical properties are improved. The Statistical Package for Social Sciences, commonly known as SPSS, quickly gained popularity in the 80s and 90s, ex-tending beyond the commercial sector to the social sciences. The original name was dropped, and the name was shortened to "SPSS." Several attempts were made to introduce a word that fits the acronym "SPSS," but they often failed. In the early 2000s, "Statistical Packages and Software Services" was used for some years, but eventually dropped. "SPSS" became just a name and was no longer short for anything. There is, however, a detailed history of SPSS from 1968 to 2009, which is available to anyone interested. The industries included in this study are the non-metal mineral product industry, general equipment manu-facturing, mining and washing of coal, textile industry, food manufacturing industry, and special equipment manufacturing. The Cronbach's Alpha reliability test was conducted, and the overall Cronbach's Alpha value for the model is 0.744, indicating a 74% reli-ability rate. Based on the literature review, a model with a Cronbach's Alpha value of over 0.50 can be considered for analysis. The text appears to be correct as it is. The Cronbach's Alpha reliability test was conducted, and the overall Cronbach's Alpha value for the model is 0.744, indicating a 74% reliability rate. Based on the literature review, a model with a Cronbach's Alpha value of over 0.50 can be considered for analysis.

Hop natural fiber-reinforced poly(butylene succinate-co-butylene adipate) (PBSA) biodegradable plastics: effect of fiber length on the performance of biocomposites

Three sizes of hop fibers were tested at 30 wt% in PBSA biocomposites for material performance. Fibre length and size distribution were found to be key factors on mechanical and thermal properties of natural fiber-reinforced composites.

Investigation of the Mechanical Properties of Flax/Jute/UHMWPE Reinforced Melamine Formaldehyde Composites Using Cone Beam Computed Tomography

ABSTRACT The research on natural fiber-reinforced composites has seen a rapid increase in recent years. The present study aims to further enhance the knowledge of composites by analyzing the mechanical properties of natural fiber-reinforced composites with flax and jute fibers. The properties of a composite are compared with those of a synthetic reinforcement like ultrahigh molecular weight polyethylene (UHMWPE). Melamine formaldefghyde (MF) is employed as a matrix for the preparation of composites. Fabrication is performed with eight layers of each fabric type to produce composite panels of 4 mm thickness. Composites are fabricated using a combination of hand lay-up and temperature-induced compression molding techniques. Mechanical characteristics, particularly, flexural, interlaminar shear, and impact strength, are investigated. Flax-reinforced composites with a flexural strength of 36 MPa, an interlaminar shear strength of 3.5 MPa, and an impact strength of 11.57 kJ/m2 fared better than jute and ultrahigh molecular weight polyethylene composites, signifying the superiority of flax fiber composites. The application of a nondestructive technique like cone-beam computed tomography provided further insight into the failure mechanisms of the composites. Scanning electron microscopy images of the impact specimens revealed failure mechanisms like fiber breakage, fibers shearing and splitting, matrix cracks, voids, and delamination.

Uncertainty analysis of mechanical behavior of natural fiber composites

The natural origin of the fibers combined with random production flaws results in significant uncertainties in the properties of natural fiber-reinforced composites. A probabilistic assessment can help to characterize the uncertainties and evaluate the reliability of natural fiber composites, enabling their use in engineering designs. To this end, this study aims to analyze the uncertainties in the tensile strength and frequency response of a unidirectional flax/epoxy composite due to the actual variability of various input parameters, including the fiber material properties and manufacturing flaws. Based on the available data in the literature, the non-deterministic input variables were divided into normal and uniform variables using a statistical test. A computationally efficient response surface approach based on the polynomial chaos expansion was proposed to conduct the uncertainty analysis with multi-type uncertain variables. Moreover, the results were validated by experimental measurements and compared with the direct Monte Carlo simulation to demonstrate the accuracy and efficiency of the surrogate model.

Machinability of Polymeric Composites and Future Reinforcements—A Review

This paper reviews the machinability and mechanical properties of natural fiber-reinforced composites. Coupling agents, operating parameters, as well as chemical treatment effects on natural fiber-reinforced composites’ machinability are also reviewed. Moreover, the impacts of fibers’ physical properties on the machinability of the composite are mentioned. Fiber volume fraction (Vf), fiber orientation as well as chemical treatment effects on mechanical properties are also defined. Conclusively, the effect of fibers’ physical properties as well as mechanical properties is described. It was discovered that chemical treatment of natural fibers improved their compatibility with the matrix by removing their surface tissues, increasing the roughness average (Ra), and reducing moisture absorption. Also, the Orientation of the fiber plays an important role in controlling the mechanical properties of the composite. Moreover, some physical properties of the fibers, including quality of fiber distributed in the matrix; fiber size, length, and diameter; moisture absorption; porosity and the way fibers break during compounding with the matrix, were found to affect the mechanical properties of the composites formed.

The Influence of Fiber Processing and Alkaline Treatment on the Properties of Natural Fiber-reinforced Composites: A Review

Throughout generations, research on natural fiber-reinforced composites (NFRCs) has been growing and yielding promising results. The notion of blending natural fibers with polymers comes from the composite’s suitable properties, not limited to low density, availability at a low price, biodegradability, and environmental friendliness. The quest for high-performing and marketable NFRCs is driving innovation in the synthesis of such materials. A suitable combination of parameters that optimizes the mechanical and functional properties of the composites without increasing the cost of production is desired. The main objective of this review is to evaluate some of the parameters that influence the behavior and properties of NFRCs. The influence of alkaline modification and natural fiber processing parameters, such as particle size, modification concentration, soaking duration, processing temperature, fiber-to-polymer ratio, and adoption of additives, on composites are discussed. This review summarizes some of the work and provides some directions in the search of an all-around performing economic NFRC.

Jute and Luffa Fiber-Reinforced Biocomposites: Effects of Sample Thickness and Fiber/Resin Ratio on Sound Absorption and Transmission Loss Performance

ABSTRACT The acoustic properties of natural fiber-reinforced composites should be identified before using these materials in various engineering applications including sound and vibration isolation. This study investigates the effects of sample thickness and fiber/resin ratio on the acoustic performance of jute and luffa fiber-reinforced biocomposites. For this purpose, jute and luffa composite samples with different thicknesses and fiber/epoxy ratios are manufactured and their sound absorption coefficients (SACs) and transmission losses (TLs) are determined using impedance tube method. Thickness-dependent tendencies of the SACs and TLs of jute and luffa composites for low-, medium-, and high-frequency ranges are identified. The effect of fiber/epoxy ratio on the acoustic properties of jute and luffa composites as a function of frequency are determined. Furthermore, the SACs and TLs of some natural fiber-based samples with different thicknesses are predicted using mathematical models and the theoretical and experimental results are compared and evaluated.

Fully Biodegradable Composites: Thermal, Flammability, Moisture Absorption and Mechanical Properties of Natural Fibre-Reinforced Composites with Nano-Hydroxyapatite.

Natural fibre-reinforced poly(lactic acid) (PLA) laminates were prepared by a conventional film stacking method from PLA films and natural fabrics with a cross ply layup of [0/90/0/90/0/90], followed by hot compression. Natural fibre (NF) nano-hydroxyapatite (nHA) filled composites were produced by the same manufacturing technique with matrix films that had varying concentrations of nHA in the PLA. Their flammability, thermal, moisture absorption and mechanical properties were analysed in terms of the amount of nHA. The flame behavior of neat PLA and composites evaluated by the UL-94 test demonstrated that only the composite containing the highest quantity of nHA (i.e., 40 wt% nHA in matrix) was found to achieve an FH-1 rating and exhibited no recorded burn rate, whereas other composites obtained only an FH-3. The thermal degradation temperature and mass residue were also observed, via thermogravimetric analysis, to increase when increasing concentrations of nHA were added to the NF composite. The tensile strength, tensile modulus and flexural modulus of the neat resin were found to increase significantly with the introduction of flax fibre. Conversely, moisture absorption was found to increase and mechanical properties to decrease with both the presence of NF and increasing concentrations of nHA, and subsequent mechanical properties experienced an obvious reduction.

Enhancement of mechanical properties of natural fiber composites via carbon nanotube addition

The effects of carbon nanotubes (CNTs) on the mechanical and fracture properties of ramie fiber-reinforced epoxy composites were investigated. Three-point bending, short beam shear, single-edge-notch bending, and Charpy impact tests were employed to evaluate the properties of ramie fiber-reinforced composites without and with CNTs modification. The fracture mechanisms were revealed with the aid of the dynamic mechanical analysis, Fourier transform infrared, and X-ray photoelectron spectroscopy. It was found that the mechanical and fracture properties of ramie fiber-reinforced composites were enhanced by incorporating multiwalled carbon nanotubes, except the impact fracture toughness. The unique chemical compositions and the multiscaled nanosized microstructures of natural fibers brought into focus new mechanisms for the improvement of the mechanical properties of natural fiber-reinforced composites.

Enhanced Functional Properties of Natural Fiber-Reinforced Composites

This paper investigates functional properties of natural fiber reinforced composites, such as strengthening characteristics, biodegradation behavior and thermal insulating properties. These functionalities are mainly derived from inherent physical and chemical characteristics of natural plant fiber. High-strength green composites can be fabricated by using strong natural fibers. The biodegradation speed of green composites is faster than that of neat biodegradable resin used as matrix. Such enhanced biodegradation properties are attributed to the preferential biodegradation reaction at interfaces between natural fiber and biodegradable matrix polymer. In addition, better thermal insulation performance is easily attained by using natural plant fibers having a larger lumen, which is the hollow middle area of the natural fibers. Thus the thermal insulation properties of the natural fiber composites can be controlled not only by changing the thermal conductivity values of matrix polymer but also by changing the internal microstructure of the natural plant fiber, namely the size of lumen.

Mechanical properties of natural fibre-reinforced composites

Natural fibres were initially used in composite materials to predominately improve bulk and reduce cost rather than improving mechanical properties. But the environmental problems associated with the production and use of synthetic fibres have changed the scenario. In the previous decade, natural fibres have been extensively used as reinforcement materials for both synthetic and bio-degradable matrices. Natural fibre reinforcements have mostly improved flexural and impact properties, but tensile strength improvement has been marginal and has been an area of investigation. Many attempts have been made towards improving mechanical properties, with efforts directed at improving the interface, newer methods of production of composites, new modelling techniques etc. In this detailed review, an attempt is made to critically analyse the various research efforts directed towards improving the mechanical properties of natural fibre reinforced composites.

Microstructures and Mechanical Properties of Natural Fibers

Natural fibers are excellent substitute materials for man made fibers in making fiber reinforced composites due to their high specific strength and modulus, low density, low price, easy availability in some countries, recyclable and degradable properties. They have raised great attentions among material scientists and engineers in the past decade. Many researches have been conducted to study the mechanical properties, especially interfacial properties of natural fiber reinforced composites. However, the properties, such as mechanical performances, moisture absorption behaviors, et. al of natural fibers themselves have been seldom investigated. Knowing the relationship between microstructures and properties of natural fibers are important for understanding the bulk properties of natural fiber composites and also good instructions for designing bio-mimic materials. In this study, four kinds of natural fibers which were extracted from different plant sources were investigated. The microstructures of these natural fibers were revealed with the aid of optical microscopy. Microstructure models were thereof set up and mechanical properties for the representative volume element were assumed. Fiber bundle fracture models together with probability statistics analysis were employed to calculate the mechanical properties of natural fibers. The results were compared with the experimental measurements. Different mechanical behaviors of natural fibers which were functioned differently in the nature were clearly explained by the above studies

Pre-treatment of Flax Fibers for use in Rotationally Molded Biocomposites

The objective of this study was to determine the effects of pre-treated flax fibers on the performance of the fiber-reinforced composites. Lack of good interfacial adhesion and poor resistance to moisture absorption make the use of natural fiber-reinforced composites less attractive. In order to improve fiber/matrix interfacial properties, fibers were subjected to chemical treatments, namely, mercerization, silane treatment, benzoylation, and peroxide treatment. Selective removal of non-cellulosic compounds constitutes the main objective of the chemical treatments of flax fibers to improve the performance of fiber-reinforced composites. Flax fibers were derived from Saskatchewan-grown flax straws. Composites consisting of high-density polyethylene (HDPE) or linear low-density polyethylene (LLDPE) or HDPE/LLDPE mix, chemically treated fibers and additives were prepared by the extrusion process. The test samples were prepared by rotational molding. The fiber surface morphology and the tensile fracture surfaces of the composites were characterized by scanning electron microscopy (SEM). The effects of the different chemical treatments on the mechanical and the physical properties of natural fiber-reinforced composites were investigated. The differential scanning calorimetry (DSC) was used to measure the melting point of the fiber-reinforced composites.