Showing papers on "Natural fiber published in 2012"

Natural Fiber Reinforced Composites

Abstract: In this review, insight into the use of bio-based fibers as composite reinforcement has been addressed. Specifics on the varieties of natural fibers, and the resultant properties from their constituents and hierarchal structures are described. The methods used to enhance the interface of these fibers with a variety of polymer matrices are reviewed. In addition, the influence of textile operations on creating various fiber architectures with resulting reinforcing capabilities, along with the methods in which natural fiber reinforced composites can be processed, are addressed. Finally, discussion of the correlation between structure, processing, and final composite properties are provided.

Effect of fiber surface treatments on mechanical and abrasive wear performance of polylactide/jute composites

Abstract: The main focus of this work is to improve the adhesion of jute fiber with polylactide (PLA). For this purpose, surface of the jute fiber was modified by alkali, permanganate, peroxide and silane treatments. The surface modified fibers were characterized by FTIR spectroscopy. Unidirectional composites were prepared with treated jute fibers and PLA matrix by hot pressing of solvent impregnated prepregs. Surface treatments resulted in enhancement of tensile and flexural properties and reduction in Izod impact strength. Dynamic mechanical analysis (DMA) results showed that, treated composites have higher storage modulus and lower tangent delta with respect to untreated composite. The degree of interfacial adhesion between the jute fiber and PLA was estimated using adhesion parameter obtained through DMA data. The results of thermogravimetric analysis (TGA) showed a higher thermal stability for silane treated composites. Experimental results on abrasive wear tests revealed that the wear resistance of composite is sensitive to fiber/matrix adhesion.

Bamboo fiber and its reinforced composites: structure and properties

Abstract: Natural plant fibers have unequivocally contributed economic prosperity and sustainability in our daily lives. Particularly, bamboo fibers have been used for industrial applications as diverse as textiles, paper, and construction. Recent renewed interest in bamboo fiber (BF) is primarily targeted for the replacement or reduction in use of glass fiber from non-renewable resources. In this review, various mechanical, chemical, and biological approaches for the preparation and separation of macro-, micro-, and nano-sized fibers from raw bamboo are summarized. The differences in the mechanical, thermal, and other properties of fibers from different materials are linked to their size, aspect ratio, surface charge and groups, and their function in nature. Biocomposites made of BF are considered to be green, environmentally responsible eco-products. Different processing parameters such as fiber extraction, surface modification, and synthesis of the composites affect the characteristics of composites. Fiber length, orientation, concentration, dispersion, aspect ratio, selection of matrix, and chemistry of the matrix must all be considered during fabrication in order to achieve desirable functionalities and performance. Because of the hydrophilic nature of BF, different methods may be adopted to improve interfacial surface adhesion. A better understanding of the fiber structure and characteristics that influence composite performance could lead to the development of additives, coatings, binders, or sizing suitable for natural fiber and a variety of polymeric matrices.

Prediction of tensile properties of hybrid-natural fiber composites

Abstract: The tensile strength and modulus of short, randomly oriented hybrid-natural fiber composite was found out experimentally and also predicted using Rule of Hybrid Mixture (RoHM). Hybrid composites were prepared using banana/sisal fibers of 40:0, 30:10, 20:20, 10:30, and 0:40 ratios, while overall fiber volume fraction was fixed as 0.4 V f . The comparison between experimental and RoHM showed that they are in good agreement.

A review on mechanical behavior of natural fiber based hybrid composites

Abstract: Hybrid composites are manufactured by combining two or more fibers in a single matrix. Hybrid composites can be made from artificial fibers, natural fibers and with a combination of both artificial and natural fibers. Hybrid composites can help us to achieve a better combination of properties than fiber reinforced composites. The constituent fibers in a hybrid composite can be altered in a number of ways leading to variation in its properties. The importance of this review can be attributed to the significant aspects of natural fiber based hybrid composites which are found to be predominantly affected by factors which include variation in fiber volume/weight fraction, variation in stacking sequence of fiber layers, fiber treatment and environmental conditions.

Thermogravimetric behavior of natural fibers reinforced polymer composites—An overview

Abstract: Natural fibers obtained from plants, known as lignocellulosic fibers are environmentally friendly alternatives for synthetic fiber, as polymer composite reinforcement. Applications of natural fiber composites are expanding in many engineering areas, from civil construction to automobile manufacturing. In recent years, a considerable number of scientific and technological works, including review papers, were dedicated to the characterization and properties of natural fibers and their composites. The mechanical behavior and the fracture characteristics are usually the most investigated and reviewed themes for the purpose of comparison to corresponding polymer composites reinforced with synthetic fibers, mainly fiberglass. The thermal behavior is also of practical interest for conditions associated with temperatures above the ambient, as in fire damage, curing or process involving heating procedures. In fact, several works also assessed distinct thermal responses, particularly in terms of thermogravimetric properties of natural fiber polymer composites. As no general review was conducted so far on the thermogravimetric (TG) behavior of these materials, this article presents an overview limited to temperature effects related to the loss of mass by means of TG analysis and the related derivative, DTG, for different polymer composites reinforced with the most common and relevant lignocellulosic fibers.

Comparative studies of mechanical and morphological properties of polylactic acid and polypropylene based natural fiber composites

Abstract: In this study, natural fiber reinforced polylactic acid composites have been developed by hot pressing through film-stacking procedure. The reinforcement materials used are nettle, Grewia optiva an...

The effect of physical parameters on sound absorption properties of natural fiber mixed nonwoven composites

Abstract: In this study, the effects of physical parameters on sound absorption properties of nonwoven fabrics were investigated. Eight different nonwoven composites including different fiber types mixed with different ratios were tested. Along with sound absorption properties, thickness, weight per area, and air permeability parameters of the samples were measured. The increase in thickness and the decrease in air permeability results in an increase in sound absorption properties of the material. The samples including 70% cotton and 30% polyester resulted in the best sound absorption coefficient in the mid-to-high frequency ranges. The increase in the amount of fiber per unit area resulted in an increase in sound absorption of the material. Addition of acrylic and polypropylene into a cotton and polyester fiber mixture increased the sound absorption properties of the composite in the low and mid-frequency ranges also.

Thermal stability and flammability of coconut fiber reinforced poly(lactic acid) composites

Abstract: This study examined the mechanical and thermophysical behavior of green composites. In the preparation procedure of the composite, a plasma treatment was applied to the surface of the coconut fibers to improve the interfacial adhesion between the fibers and matrix. The coconut fiber-reinforced PLA composites were prepared using the commingled yarn method. The mechanical properties of the composites, such as tensile strength, Young’s modulus, and elongation at break were examined, and the shrinkage and flame retardant properties of the specimens were measured. From these experiments, the effect of the plasma treatment on the mechanical and thermophysical behavior of the coconut fibers/PLA composites was identified. In addition, morphological analysis was performed using scanning electron microscopy.

Effect of diameters and alkali treatment on the tensile properties of date palm fiber reinforced epoxy composites

Abstract: Natural fibers as reinforced polymer composites have recently been the center of attention among researchers. Surface modifications and variations in the fiber diameters are major factors that influence the fiber adhesion performance inside the matrix. Experiments have been performed to further the development of natural fiber reinforced polymers as a replacement for glass fibers. In the present research, date palm fibers (DPFs) with three different size ranges of diameters (800–600, 600–400, and 400–200 μm) and the influence of alkali treatment on their characteristics have been investigated. Morphology observations (SEM), EDS density mapping (quantitative elemental analysis), X-RD, and FTIR spectroscopy of treated and untreated fibers were carried out. In addition, the tensile properties of a single fiber and composites consisting of fibers/epoxy with discontinuous random oriented short fibers both with and without chemical modification were studied. The results showed that DPFs are amenable to chemical modification particularly in the fine fiber case. It was found that the ultimate tensile strength and percentage elongation of a single fiber after alkali treatment increased by 57% and 24.7 %, respectively. Because alkali treatment of the DPFs was able to provide a good adhesion within the matrix, the tensile strength, elastic modulus and the fiber-matrix interaction of the composite were improved. Collectively, the addition of the proposed DPFs may open a new avenue for the exploitation of this natural cheap material to produce a green composite.

A Study on Moisture Absorption and Swelling in Bio-Based Jute-Epoxy Composites

Abstract: Woven jute fibers, a class of affordable and biodegradable ‘green’ fibers, are being increasingly used as a substitute for the artificial glass and carbon fibers used in polymer composites. However, all natural fiber composites absorb water and swell in a moist environment. For the first time, the swelling and weight gain behavior of bio-based composites made from jute fibers and bio-based or ordinary epoxy is presented in this experimental characterization study. Several such composites specimens were made using a low-pressure resin injection process similar to resin transfer molding; the specimens were made according to ASTM D 570 consisted of three compositions: pure resin, pure resin with a single jute fabric layer, and pure resin with two jute fabric layers. The effects of number of layers on moisture absorption, thickness swelling, volume swelling, and density were measured as a function of immersion time. It is observed that the moisture diffusion rate into composites increases with an increase in the jute-fiber-to-epoxy ratio. The type of epoxy used as the matrix appeared to have an influence on the moisture absorption percentages of the composites – the study showed that both water absorption and swellings were higher in the bio-epoxy parts compared to the epoxy parts. The swelling of composites was correlated with an increase in diameters of jute fiber in water and possibilities for the appearance of micro-cracks around fibers in composites were discussed. The data on moisture absorption, thickness swelling, and volume swelling of bio-based composites made from woven jute fibers, and bio-based and ordinary epoxies presented in this article will lead to a better understanding of how these composites react in wet environmental conditions.

Review of Natural Fibers. Part I—Vegetable Fibers

Abstract: Natural fibers, which are an important part of human environment, are also valuable raw materials used for textile and non-textile production. Diversity of natural fiber shapes and forms is caused by their occurrence in different climatic zones. The abundance of the fiber sources arouses interest and gives opportunity for more comprehensive studies and, what follows, finding new applications for the fibers in industry. This paper presents collection of well- and little-known natural fibers from exotic plants that come from various climatic zones. Image analysis conducted by SEM techniques is a reliable method for evaluation of parameters characterizing surface and cross section of natural fibers. Some information about properties and application of the fibers is also provided.

Mechanical behavior of carbon/flax hybrid composites for structural applications

Abstract: In this work, the influence of an unidirectional carbon fabric layer on the mechanical performances of bidirectional flax fabric/epoxy composites used for structural applications was studied. Two d...

Mercerization Treatment Parameter Effect on Natural Fiber Reinforced Polymer Matrix Composite: A Brief Review

Abstract: Environmental awareness and depletion of the petroleum resources are among vital factors that motivate a number of researchers to explore the potential of reusing natural fiber as an alternative composite material in industries such as packaging, automotive and building constructions. Natural fibers are available in abundance, low cost, lightweight polymer composite and most importance its biodegradability features, which often called “ecofriendly” materials. However, their applications are still limited due to several factors like moisture absorption, poor wettability and large scattering in mechanical properties. Among the main challenges on natural fibers reinforced matrices composite is their inclination to entangle and form fibers agglomerates during processing due to fiber-fiber interaction. This tends to prevent better dispersion of the fibers into the matrix, resulting in poor interfacial adhesion between the hydrophobic matrix and the hydrophilic reinforced natural fiber. Therefore, to overcome this challenge, fiber treatment process is one common alternative that can be use to modify the fiber surface topology by chemically, physically or mechanically technique. Nevertheless, this paper attempt to focus on the effect of mercerization treatment on mechanical properties enhancement of natural fiber reinforced composite or so-called bio composite. It specifically discussed on mercerization parameters, and natural fiber reinforced composite mechanical properties enhancement. Keywords—Mercerization treatment, mechanical properties, natural fiber and bio composite

Properties of natural fiber composites made by pultrusion process

Abstract: Great efforts are being made at Brunel University, UK in attempt to develop natural fiber composites with desired structure and good overall properties for construction. This work focuses on the mechanical and morphological characterization of the pultruded composite rods made from hemp and wool fiber reinforcements. The results showed that the composite using polyurethane resin system has higher specific tensile and compressive strength as well as the Young's and compressive moduli compared with the polyester and vinyl ester composites, while the polyester composite exhibits better flexural strength. The SEM observation of the cross section and layered polyester and polyurethane composites has found defects on the interface of fibers and resin matrix. It is also revealed that fibers are not evenly distributed in the composites and more resin aggregates in areas close to rod surface. Meanwhile, voids have been noticed existing in both composites, but more of them are found in the polyurethane-matrix rod, ...

Fracture Toughness Investigation on Long Kenaf/Woven Glass Hybrid Composite Due To Water Absorption Effect

Abstract: Water absorption of natural fiber composite is of serious concerned especially for outdoor application. In this study, long kenaf/woven glass hybrid composite is fabricated in-house using cold press technique. The effect of water absorption on the hybrid composites is investigated at room temperature under three different environmental conditions, i.e. distilled water, rain water, and sea water. The moisture absorption amount is obtained by calculating the different percentage weight before and after the immersion process. The moisture content is found to exhibit non-Fickian behaviour regardless of three different conditions. Liquid exposure of long kenaf/woven glass hybrid composite deteriorates the fracture toughness due to the weakening of interface between fiber and matrix. There are also several recognized modes of humidity aging found through SEM observation.

Mechanical properties of kenaf/fiberglass polyester hybrid composite

Abstract: In a view to reduce the cost of production and the harmful destruction in normal environment, there's a lot of research have been conducted or still ongoing for the possibility of using natural fibers which are wholly degradable in the combination of biodegradable thermoplastic materials. This research will focus on Kenaf; an extremely valuable natural fiber with robust mechanical properties. In this research, kenaf fiber/fiberglass reinforced with unsaturated polyester composites were subjected to water absorption test. Water absorption test were conducted by immersing specimens into three different environmental conditions including sea water, distilled water and rain water (acidic solutions) at room temperature from 1st day until 4th week. The effect of the mechanical strength of the hybrid composties is investigated. In general, the mechanical properties of kenaf fiber are deteriorated after the moisture penetrates into the composite. The strain to failure increases from 1st day until 3rd week followed by a drastically drop at 4th week. The humidity aging is one of the evidence found in SEM micrograph which contributes to the reduction of tensile modulus.

Effect of physicochemical structure of natural fiber on transverse thermal conductivity of unidirectional abaca/bamboo fiber composites

Abstract: To study the effect of the microstructure of natural fiber on the transverse thermal conductivity of unidirectional composite, abaca and bamboo fibers were unidirectionally aligned to fabricate epoxy composites by a resin transfer molding (RTM) technique. The transverse thermal conductivity of these two types of composites was measured in a steady-state platform. X-ray diffractometer and scanning electron microscopy were applied to analyze the microstructure and morphology of both fibers and composites. The results indicated that the transverse thermal conductivity showed two types of tendencies with fiber content increasing: increasing for bamboo fiber composites, and decreasing for abaca fiber composites. The microstructure and theoretical analysis suggest that the lumen structure plays a great role rather than crystal structures and chemical compounds on the transverse thermal conductivity of unidirectional composites, which is useful for further development and design of natural fiber reinforced composites with better thermal insulation property for people’s daily life.

Studies on the characterization of piassava fibers and their epoxy composites

Abstract: This paper presents morphology, physical and strength properties of piassava fiber, a very rigid fiber having a potential to be used as composite reinforcement. Composites of continuous and aligned piassava fibers with and without alkali treatment dispersed in epoxy matrix were subjected to three point bend, tensile, and Izod impact tests. Composites with fibers above 20 vol.% showed an effective reinforcement behavior both in flexural and tensile tests, while the impact energy linearly increased for the amount of piassava fibers used in this study. Fractographic study revealed a relatively weaker fiber/matrix adhesion acting as preferential site for crack nucleation. Evidence was also found for crack arrest by the fiber above 20 vol.%. This, together with spiny surface protrusion in the piassava fibers, was found to be responsible for the reinforcement of the epoxy composites.

Influence of natural fibers on the mechanical properties and biodegradation of poly(lactic acid) and poly(ε-caprolactone) composites: A review

Abstract: This article highlights developments in viable poly(lactic acid) (PLA) and poly(e-caprolactone) (PCL) ecofriendly products with enhanced mechanical properties and biodegradation based on natural resources for both reinforcements and matrices. In recent times, several techniques have emerged with emphasis on enhancing mechanical, biological, and chemical properties equivalent to or superior to conventional polymers in use. Chemical and physical modifications of the fibers and in some cases polymer matrix or both are used to obtain properties suitable for the intended application. The mechanical properties and biodegradation of PLA and PCL natural fiber composites were enhanced by the treated fibers.