Showing papers on "Natural fiber published in 2020"

A review of natural fiber composites: properties, modification and processing techniques, characterization, applications

Abstract: There has been much effort to provide eco-friendly and biodegradable materials for the next generation of composite products owing to global environmental concerns and increased awareness of renewable green resources. An increase in the use of natural materials in composites has led to a reduction in greenhouse gas emissions and carbon footprint of composites. In addition to the benefits obtained from green materials, there are some challenges in working with them, such as poor compatibility between the reinforcing natural fiber and matrix and the relatively high moisture absorption of natural fibers. Green composites can be a suitable alternative for petroleum-based materials. However, before this can be accomplished, there are a number of issues that need to be addressed, including poor interfacial adhesion between the matrix and natural fibers, moisture absorption, poor fire resistance, low impact strength, and low durability. Several researchers have studied the properties of natural fiber composites. These investigations have resulted in the development of several procedures for modifying natural fibers and resins. To address the increasing demand to use eco-friendly materials in different applications, an up-do-date review on natural fiber and resin types and sources, modification and processing techniques, physical and mechanical behaviors, applications, life-cycle assessment, and other properties of green composites is required to provide a better understanding of the behavior of green composites. This paper presents such a review based on 322 studies published since 1978.

Nanocellulose Reinforced Thermoplastic Starch (TPS), Polylactic Acid (PLA), and Polybutylene Succinate (PBS) for Food Packaging Applications.

Abstract: Synthetic plastics are severely detrimental to the environment because non-biodegradable plastics do not degrade for hundreds of years. Nowadays, these plastics are very commonly used for food packaging. To overcome this problem, food packaging materials should be substituted with "green" or environmentally friendly materials, normally in the form of natural fiber reinforced biopolymer composites. Thermoplastic starch (TPS), polylactic acid (PLA) and polybutylene succinate (PBS) were chosen for the substitution, because of their availability, biodegradability, and good food contact properties. Plasticizer (glycerol) was used to modify the starch, such as TPS under a heating condition, which improved its processability. TPS films are sensitive to moisture and their mechanical properties are generally not suitable for food packaging if used alone, while PLA and PBS have a low oxygen barrier but good mechanical properties and processability. In general, TPS, PLA, and PBS need to be modified for food packaging requirements. Natural fibers are often incorporated as reinforcements into TPS, PLA, and PBS to overcome their weaknesses. Natural fibers are normally used in the form of fibers, fillers, celluloses, and nanocelluloses, but the focus of this paper is on nanocellulose. Nanocellulose reinforced polymer composites demonstrate an improvement in mechanical, barrier, and thermal properties. The addition of compatibilizer as a coupling agent promotes a fine dispersion of nanocelluloses in polymer. Additionally, nanocellulose and TPS are also mixed with PLA and PBS because they are costly, despite having commendable properties. Starch and natural fibers are utilized as fillers because they are abundant, cheap and biodegradable.

Thermal stability of natural fibers and their polymer composites

Abstract: Natural fiber-based composites are applied in many structural engineered products from civil constructions to automobile manufacturing due to the properties such as low density, high aspect ratio, biodegradability and ease to work. During the past decades such composites have been thoroughly studied for their mechanical properties and failure behavior and their properties compared with those of synthetic fiber-based composites. Other properties, such as the thermal behavior of natural fibers and composites, have also been studied because they determine the performance of their products possible. It deals with the effect of temperature on adhesive curing, effect of high temperature and fire damage during fabrication. Further, the thermal properties have equal importance in structural applications such as temperature transfer from end to end, load capacity at specific temperature, material behavior and dimensional stability at high temperature. In this respect the isothermal and non-isothermal thermogravimatric analyses are discussed and the improtance of glass transition temperature is studied during prepapration of composites to ensure their ultimate properties. Although there are several works that have been done on thermal behavior, especially thermogravimetric analysis of natural fibers and their composites, there is no review article available specially focused on natural fiber-based composites, hybrid composites, and nanocomposites. The aim of this review was to focus on the advances in the comprehension of thermogravimetric behavior of natural fibers and compare the effect of natural fibers as reinforced materials in polymer composites.

Mechanical performance of oil palm/kenaf fiber-reinforced epoxy-based bilayer hybrid composites

Abstract: Owing to the recent trend and increasing awareness toward sustainable product design, natural fiber-based materials are gaining a revival popularity to replace synthetic fiber in the compos...

PLA Composites Reinforced with Flax and Jute Fibers-A Review of Recent Trends, Processing Parameters and Mechanical Properties.

Abstract: Multiple environmental concerns such as garbage generation, accumulation in disposal systems and recyclability are powerful drivers for the use of many biodegradable materials. Due to the new uses and requests of plastic users, the consumption of biopolymers is increasing day by day. Polylactic Acid (PLA) being one of the most promising biopolymers and researched extensively, it is emerging as a substitute for petroleum-based polymers. Similarly, owing to both environmental and economic benefits, as well as to their technical features, natural fibers are arising as likely replacements to synthetic fibers to reinforce composites for numerous products. This work reviews the current state of the art of PLA compounds reinforced with two of the high strength natural fibers for this application: flax and jute. Flax fibers are the most valuable bast-type fibers and jute is a widely available plant at an economic price across the entire Asian continent. The physical and chemical treatments of the fibers and the production processing of the green composites are exposed before reporting the main achievements of these materials for structural applications. Detailed information is summarized to understand the advances throughout the last decade and to settle the basis of the next generation of flax/jute reinforced PLA composites (200 Maximum).

Fabrication and characterization of coir/carbon-fiber reinforced epoxy based hybrid composite for helmet shells and sports-good applications: influence of fiber surface modifications on the mechanical, thermal and morphological properties

Abstract: Coconut-coir, a natural fiber, strong and lightweight, abundantly in India and Vietnam, can be an excellent choice to produce polymer composites. Due to the higher specific modulus and durability, these composites have a myriad of applications. This article provides a novel experimental research study on the fabrication and investigation of mechanical as well as thermal behavior of coir fiber/woven-carbon fiber/epoxy resin hybrid composite. The composite samples were formulated with distinct fiber weight percentages viz. 30%, 20%, and 10% using the vacuum bagging technique. Mechanical behavior (tensile, compressive, flexural, and impact strength) and thermal behavior (Thermogravimetric analysis) of coir fiber/carbon fiber/epoxy resin hybrid composites were studied according to the ASTM standards. Moreover, Scanning Electron Microscopy (SEM) was performed to examine the morphological characterization of tensile fractography specimens and analyze the properties of the fiber/matrix bonding of the surface before and after alkaline treatment. The treated fiber shows good matrix binding and less fiber pull-out as compared with untreated fibers. The result also revealed that the hybrid composite has more robust properties under mechanical loading than single fiber-reinforced composite.

Sound Absorption Properties of Natural Fibers: A Review

Abstract: In recent years, in an attempt to substitute the conventional synthetic sound absorption material, natural fibers and their sound absorption properties have been increasingly studied. This is due to the fact that conventional synthetic fiber has potential health risks for human beings and significant environmental impact. In this review, existing and newly emerging natural fiber sound absorbers are summarized and highlighted in three categories: raw material, fiber assembly and composite. The sound absorption mechanism, several widely used prediction models and the popular acoustic characterization methods are presented. The comparison of sound absorption properties between some natural sound absorbers and glass fiber is conducted in two groups, i.e., thin material and thick material. It is found that many natural fibers have comparable sound absorption performance, some of them can be the ideal alternatives to glass fiber, such as kapok fiber, pineapple-leaf fiber and hemp fiber. Last, the conclusion part of this review gives an outlook regarding the promotion of the commercial use of natural fiber by means of theoretical study, efficient and environmentally friendly pretreatment and Life Cycle Assessment.

Characterization Study of Empty Fruit Bunch (EFB) Fibers Reinforcement in Poly(Butylene) Succinate (PBS)/Starch/Glycerol Composite Sheet

Abstract: In this study, a mixture of thermoplastic polybutylene succinate (PBS), tapioca starch, glycerol and empty fruit bunch fiber was prepared by a melt compounding method using an industrial extruder. Generally, insertion of starch/glycerol has provided better strength performance, but worse thermal and water uptake to all specimens. The effect of fiber loading on mechanical, morphological, thermal and physical properties was studied in focus. Low interfacial bonding between fiber and matrix revealed a poor mechanical performance. However, higher fiber loadings have improved the strength values. This is because fibers regulate good load transfer mechanisms, as confirmed from SEM micrographs. Tensile and flexural strengths have increased 6.0% and 12.2%, respectively, for 20 wt% empty fruit bunch (EFB) fiber reinforcements. There was a slightly higher mass loss for early stage thermal decomposition, whereas regardless of EFB contents, insignificant changes on decomposition temperature were recorded. A higher lignin constituent in the composite (for high natural fiber volume) resulted in a higher mass residue, which would turn into char at high temperature. This observation indirectly proves the dimensional integrity of the composite. However, as expected, with higher EFB fiber contents in the composite, higher values in both the moisture uptake and moisture loss analyses were found. The hydroxyl groups in the EFB absorbed water moisture through formation of hydrogen bonding.

Recent Developments in Luffa Natural Fiber Composites: Review

Abstract: Natural fiber composites (NFCs) are an evolving area in polymer sciences. Fibers extracted from natural sources hold a wide set of advantages such as negligible cost, significant mechanical characteristics, low density, high strength-to-weight ratio, environmental friendliness, recyclability, etc. Luffa cylindrica, also termed luffa gourd or luffa sponge, is a natural fiber that has a solid potential to replace synthetic fibers in composite materials in diverse applications like vibration isolation, sound absorption, packaging, etc. Recently, many researches have involved luffa fibers as a reinforcement in the development of NFC, aiming to investigate their performance in selected matrices as well as the behavior of the end NFC. This paper presents a review on recent developments in luffa natural fiber composites. Physical, morphological, mechanical, thermal, electrical, and acoustic properties of luffa NFCs are investigated, categorized, and compared, taking into consideration selected matrices as well as the size, volume fraction, and treatments of fibers. Although luffa natural fiber composites have revealed promising properties, the addition of these natural fibers increases water absorption. Moreover, chemical treatments with different agents such as sodium hydroxide (NaOH) and benzoyl can remarkably enhance the surface area of luffa fibers, remove undesirable impurities, and reduce water uptake, thereby improving their overall characteristics. Hybridization of luffa NFC with other natural or synthetic fibers, e.g., glass, carbon, ceramic, flax, jute, etc., can enhance the properties of the end composite material. However, luffa fibers have exhibited a profuse compatibility with epoxy matrix.

Acoustic, Mechanical and Thermal Properties of Green Composites Reinforced with Natural Fibers Waste.

Abstract: The use of acoustic panels is one of the most important methods for sound insulation in buildings. Moreover, it has become increasingly important to use green/natural origin materials in this area to reduce environmental impact. This study focuses on the investigation of acoustic, mechanical and thermal properties of natural fiber waste reinforced green epoxy composites. Three different types of fiber wastes were used, e.g., cotton, coconut and sugarcane with epoxy as the resin. Different fiber volume fractions, i.e., 10%, 15% and 20% for each fiber were used with a composite thickness of 3 mm. The sound absorption coefficient, impact strength, flexural strength, thermal conductivity, diffusivity, coefficient of thermal expansion and thermogravimetric properties of all samples were investigated. It has been found that by increasing the fiber content, the sound absorption coefficient also increases. The coconut fiber-based composites show a higher sound absorption coefficient than in the other fiber-reinforced composites. The impact and flexural strength of the cotton fiber-reinforced composite samples are higher than in other samples. The coefficient of thermal expansion of the cotton fiber-based composite is also higher than the other composites. Thermogravimetric analysis revealed that all the natural fiber-reinforced composites can sustain till 300 °C with a minor weight loss. The natural fiber-based composites can be used in building interiors, automotive body parts and household furniture. Such composite development is an ecofriendly approach to the acoustic world.

Investigation of the Potential Use of Curauá Fiber for Reinforcing Mortars

Abstract: Curaua is a bromeliad of Amazonian origin, present in some states in the northern region of Brazil and in other countries in South America. Its natural fibers have several technological advantages for application in composite materials. The objective of this research was to investigate the potential of using the fiber of Curaua as a reinforcement element in mortars for wall covering. Mortars were made with a 1:1:6 ratio (cement:lime:sand) in relation to their mass, evaluating the effect of adding 1%, 2% and 3% of Curaua fiber natural and fiber treated in NaOH solution in relation to the mass of cement, compared to the reference mixture (0%). Technological properties such as consistency, water retention and incorporated air content, compressive strength, water absorption and durability in wetting and drying cycles were evaluated. The results showed that the addition of the Curaua fiber causes an improvement in the mechanical properties of mortars, and at levels of addition 3% or more, it causes problems of workability and incorporation of air into the dough, thus, the fiber addition in 2% presented better results for application in coating mortars, in relation a Brazilian norm, even improving the durability of external coatings.

Development of mortar for laying and coating with pineapple fibers

Abstract: Brazil is one of the largest producers of pineapple in the world, which, in addition to bringing substantial benefits, contributes to increasing waste generation in the stages of processing, aiming at its consumption. The Brazilian environmental legislation has been increasingly more restrictive with respect to the disposal of solid waste, whether domestic, industrial or agro-industrial, which has stimulated studies related to the use of these materials in several matrices. This study aimed to evaluate the potentiality of using the natural fiber of pineapple (Ananas comosus), extracted from its leaves, as reinforcing material in cementitious composites. For this purpose, natural fiber extracted from the pineapple crown was incorporated in different percentages in relation to the cement mass: 0, 2.5, 5, 7.5 and 10%, and the fibers obtained were submerged in aqueous NaOH solution with 5% concentration in volume, for 1 h at room temperature. The following variables were evaluated: consistency, water retention, incorporated air, mass density in hardened state, mechanical strength, water absorption by immersion and capillarity, besides verifying the influence of the mode of fiber incorporation. It was observed that the treatment with NaOH solution and the percentage of natural pineapple fiber incorporated in up to 5% in relation to the cement mass form mortars with technological feasibility.

Effects of fiber geometry and orientation distribution on the anisotropy of mechanical properties, creep behavior, and thermal expansion of natural fiber/HDPE composites

Abstract: Natural fiber/high-density polyethylene (HDPE) composites (NFPCs) were fabricated via extrusion using three types of natural fibers from poplar wood (PW), radiata pine (RP), and rice husk (RH), respectively. The specimens were cut from the extruded samples at various off-axis angles (from 0° to 90°). The effect of fiber geometry and orientation distribution on the mechanical properties, creep behavior, and thermal expansion of the NFPCs was investigated. The natural fibers in the composites showed a preferential orientation along the extrusion direction, as evidenced by the optics micrographs. The flexural properties and impact strength of the NFPCs were the highest at zero angle and decreased considerably with increasing orientation angle, which was further validated by the finite element analysis. At zero angle, the PW/HDPE composites had the highest flexural and impact strength and the smallest creep strain and thermal expansion, but a small difference in mechanical properties was observed at 90° among the NFPCs. The significant anisotropy of properties at various angles of the PW/HDPE composites was due to the high aspect ratio (L/D) of poplar wood fiber. These results indicate that high fiber L/D and orientation distribution had a beneficial effect on the properties of NFPCs.

Chemical Composition and Mechanical Properties of Natural Fibers

Abstract: Natural Fiber (NF) becomes a vital part of the various industries such as textile, automotive, packaging, construction, etc. nowadays. This is a review of the chemical composition and mechanical pr...

Effect of moisture absorption on the mechanical performance of natural fiber reinforced woven hybrid bio-composites

Abstract: In the present study, moisture uptake behavior and their effect on mechanical properties of plant fibers were investigated while these fibers were reinforced with epoxy matrix. The develope...

A Review on Natural Fiber-Reinforced Geopolymer and Cement-Based Composites.

Abstract: The use of ecological materials for building and industrial applications contributes to minimizing the environmental impact of new technologies. In this context, the cement and geopolymer sectors are considering natural fibers as sustainable reinforcement for developing composites. Natural fibers are renewable, biodegradable, and non-toxic, and they exhibit attractive mechanical properties in comparison with their synthetic fiber counterparts. However, their hydrophilic character makes them vulnerable to high volumes of moisture absorption, thus conferring poor wetting with the matrix and weakening the fiber-matrix interface. Therefore, modification and functionalization strategies for natural fibers to tailor interface properties and to improve the durability and mechanical behavior of cement and geopolymer-based composites become highly important. This paper presents a review of the physical, chemical and biological pre-treatments that have been performed on natural fibers, their results and effects on the fiber-matrix interface of cement and geopolymer composites. In addition, the degradation mechanisms of natural fibers used in such composites are discussed. This review finalizes with concluding remarks and recommendations to be addressed through further in-depth studies in the field.

Acoustic and mechanical characterisation of polypropylene composites reinforced by natural fibres for automotive applications

Abstract: In recent days, polymer composites reinforced with natural fiber had shown greater focus and interest in the production of environmentally sustainable materials and in part in the replacement of synthetic fibers commonly used in automotive applications. In this study, an attempt has been made to investigate the effect of natural fibers obtained for composite preparation from milkweed, kusha grass, sisal, banana and hay mixed with polypropylene 10:90 (wt %). Mechanical properties such as tensile strength and hardness have been determined in accordance with ASTM standards. Water absorption studies have also been done to investigate the water's absorption ability. The acoustic characterization of these natural reinforced fiber composites is measured by a thickness of 10 mm and 20 mm. The result has shown that an increase in thickness is not effective at higher acoustic absorption frequencies. Scanning electron microscope analyzes microstructures of milkweed fiber. These results identify suitable materials for different mechanical and automotive applications.

Mechanical and Thermal Characterization of Natural Intralaminar Hybrid Composites Based on Sisal.

Abstract: The main objective of this work was to investigate the effect of hybridization on the mechanical and thermal properties of intralaminar natural fiber-reinforced hybrid composites based on sisal. Ramie, sisal and curaua fibers were selected as natural fiber reinforcements for the epoxy matrix based composites, which were produced by the hand lay-up technique. Tensile, flexural and impact tests were carried out according to American society for testing and materials (ASTM) standards to characterize the hybrid composites, while differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to evaluate the thermal properties. It was found that the mechanical properties are improved by hybridization of sisal based composites. The thermal analysis showed that the hybridization did not significantly affect the thermal stability of the composites. A scanning electron microscopy (SEM) was used to examine the fracture surface of the tested specimens. The SEM images showed a brittle fracture of the matrix and fiber breakage near the matrix.

High-Strength Polylactic Acid (PLA) Biocomposites Reinforced by Epoxy-Modified Pine Fibers

Abstract: The stiffness and tensile strength of biopolymers (e.g., polylactic acid (PLA)) are less than desirable for load-bearing applications in their neat form. The use of natural fibers as reinforcements...

Study on Mechanical, Thermal and Morphological Properties of Banana Fiber-Reinforced Epoxy Composites

Abstract: In recent decades, engineering applications involving polymer composites reinforced with natural fibers have increased significantly due to the advantages not only of favorable composite properties but also of fiber durability and environmental friendly nature. In the present work composites reinforced with upto 20 wt% fabric made of banana, a relatively known natural fiber from India. These banana fibers were cut into a similar average length of 10 and 20 mm and two sets of bio-composites were prepared by compression moulding process with varying weight percentage of epoxy resin by 0, 5, 10, 15 and 20%. Experimental results showed tensile, flexural and impact strength of bio-composites with up to 15 wt% has increased compared with neat epoxy. However, the mechanical strength has decreased above 15 wt% fiber reinforcement. This is a study of thermogravimetric analysis (TGA) that banana fiber-reinforced composites have high thermal stability up to 220 oC.