Showing papers on "Natural fiber published in 2018"

Influence of chemical treatments on mechanical properties of hemp fiber reinforced composites

Abstract: Natural Fibers Reinforced Composites (NFRC) are finding much interest as a substitute for glass or carbon reinforced polymer composites, like for instance automobile interior linings (roof, rear wall, side panel lining), shipping pallets, construction products (i.e. composite roof tiles), furniture and household products (i.e. storage containers, window and picture frames as well as food service trays, toys and flower pots) as well as fan houses and blades. However, a notable disadvantage of lignocellulosic fibers as reinforcements is their polarity which makes it incompatible with hydrophobic thermoplastic matrix. This incompatibility results in poor interfacial bonding between the fibers and the matrix. This in turn leads to impaired mechanical properties of the composites. This defect can be remedied by chemical modification of fibers so as to make it less hydrophilic. In this paper experiments have been performed to further the development of natural fiber reinforced composites. Untreated and treated surfaces of hemp fibers were characterized using Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). Fiber-matrix adhesion was promoted by fiber surface modifications using an alkaline treatment and (3-Glycidyloxypropyl) trimethoxysilane coupling agent. The mechanical behaviour of epoxy matrix composite reinforced with woven hemp was studied and mechanical test results show that silane treatment of hemp fibers improves, both tensile and flexural properties of the composites, although no high values are obtained.

Studies on Mechanical and Morphological Characterization of Developed Jute/Hemp/Flax Reinforced Hybrid Composites for Structural Applications

Abstract: In the present study, an attempt has been made to develop and characterize natural fiber-based composites (jute/epoxy, hemp/epoxy, flax/epoxy) and their hybrid composites (jute/hemp/epoxy, hemp/fla...

Tensile and flexural properties of natural fiber reinforced polymer composites: A review:

Abstract: In recent years, researchers and scientists are facing problems in terms of environmental imbalance and global warming owing to numerous use of composite materials prepared by synthetic fibers and

An Investigation on Wear and Dynamic Mechanical behavior of Jute/Hemp/Flax Reinforced Composites and Its Hybrids for Tribological Applications

Abstract: Bio-materials have ignited a quest among research fraternity to be used in every possible field of applications like automobile, sports, medical, civil and textile industry. Application spectrum of natural fiber reinforced polymer composites is spreading globally in every field of engineering having structural and tribological applications. The present work investigates the tribological performance of regionally available inexpensive plant based natural fiber reinforced polymer composites. In this work, three different types of natural fibers (jute, hemp, and flax) were reinforced with epoxy matrix to fabricate natural fiber reinforced polymer composites (NFRP) and their hybrid composites (jute/hemp/Epoxy, hemp/flax/epoxy and jute/ hemp/flax/epoxy) using hand-layup technique. Tribological performance of the developed bio-composites were evaluated in terms of frictional characteristics and sliding wear under dry contact condition at different process parameters, such as applied load (10-50 N), sliding speed (1-5 m/s) and sliding distance (1000-2000 m). Experimental results of wear analysis confirmed that incorporation of natural fibers into epoxy polymer matrix significantly improved the wear behavior of the developed NFRP composites in comparison to neat epoxy polymer. Among all the developed composites, jute/epoxy composite achieved the highest coefficient of friction, frictional force and specific wear rate. Dynamic mechanical analysis (DMA) was also analyzed to evaluate the viscoelastic behavior of the developed composites. The surface morphology of samples after wear test was examined by scanning electron microscopy to investigate and propose the possible wear mechanism of the developed composites.

Effects of hybridization and hybrid fibre dispersion on the mechanical properties of woven flax-carbon epoxy at low carbon fibre volume fractions

Abstract: Natural and synthetic fibers are increasingly being used as reinforcements in various applications While the latter is popular for its generally superior mechanical properties, natural fibers are eco-friendly, cheap and have good vibro-acoustic properties As more businesses are investing in green and sustainable technologies, natural fibers have been gaining attention in recent years and are already being used in various applications such as car interior, sporting equipment, etc To date, their applications have been limited to those not requiring very demanding mechanical performance In this paper, mechanical performance enhancement of natural fiber composites through hybridization with carbon fibers was benchmarked against one of the strongest and stiffest natural fibres, flax, through various interlayer flax-carbon hybrids at low carbon fibre volume fractions Besides strength and stiffness characterization of hybrid laminates, this work investigates the effects of interlaminar hybrid fiber dispersion on tensile performance The results suggested that morphology of mating hybrid plies might affect stiffness in woven fabrics Hybrid laminates with single carbon plies interspersed with flax plies displayed lower tensile stiffness due to absence of nesting of the stiffer woven carbon plies and architectural crimp mismatch between flax and carbon woven fabrics Comparisons with rule of hybrid mixture predictions showed reasonably good agreement in hybrid laminates exhibiting linear behavior, but significant over-predictions in highly dispersed laminates due to large deviations from linearity

Biocomposites of different lignocellulosic wastes for sustainable food packaging applications

Abstract: The suitability of three local lignocellulosic wastes i.e. almond shell (AS), rice husk (RH) and seagrass (SG) as fillers in PHB/Fiber composites applications has been studied. PHB/Fiber composites with 10 phr and 20 phr fiber content were prepared by melt blending. The influence of the fiber type (size, morphology and origin) and content on the morphological, mechanical and thermal properties of the as obtained composites has been assessed. To evaluate the potential use in food packaging applications, the barrier performance to water, thermoforming ability and disintegration in controlled composting conditions of the composites were also studied. All the fibers have demonstrated to be apt for their use as fillers in PHB/Fiber composites, showing a reinforcing effect without affecting the crystallinity and the disintegration rate of PHB. The thermal stability and the water barrier performance of the composites were reduced by the presence of the fibers. Nevertheless, the addition of AS resulted in the best balance of properties, in terms of permeability and mechanical properties, finding an enhancement of the thermoforming ability of PHB when 10 phr of AS was added.

The challenges of natural fiber in manufacturing, material selection, and technology application: A review:

Abstract: In this review, previous studies about the properties and applications of natural fiber composites in the aerospace and automobile fields will be discussed. Natural fiber composites are a better al...

Physicochemical Properties of New Cellulosic Fibers from Azadirachta indica Plant

Abstract: This research study was aimed at examining newly identified natural fiber from the bark of Azadirachta indica (AI). The various properties were analyzed and compared with other available bark fibers. The chemical composition of Azadirachta indica fibers (AIFs), high cellulose (68.42 wt.%) content, and low lignin (13.58 wt.%) were discovered. The lower density of 740 kg/m3, and crystallinity index of 65.04% properties were identified. The maximum peak temperature obtained was 321.2 °C in Differential thermogravimetry (DTG) curve. Taken together, all the properties of AIFs indicated that they could be suitable to make green composites for various types of applications.

Polydopamine induced natural fiber surface functionalization: a way towards flame retardancy of flax/poly(lactic acid) biocomposites

Abstract: Aiming to improve flame retardancy of natural fiber reinforced poly (lactic acid) (PLA) composites, a bio-inspired fiber surface modification approach was investigated in this study. Raw flax fiber was firstly coated with a thin adhesive polydopamine (PDA) film in an aqueous solution of dopamine, followed by in situ growth of iron phosphonate on the fiber surface. The modified flax fiber was added into PLA to prepare flame retardant biocomposite. Compared with raw flax reinforced PLA with a limiting oxygen index (LOI) of 19.1% and no rating in vertical burning test (UL-94), the modified PLA composite possessed a high LOI of 26.1% and V-2 rating. Meanwhile, the fiber surface modification resulted in suppression on both peak heat release rate (decreased by 16%) and total smoke production (decreased by 21%) in cone calorimeter test (CCT). Moreover, tensile modulus of the flame retardant composite was remarkably enhanced, accompanied with a slightly decreased tensile strength compared to raw PLA. The polydopamine assisted surface modification proved to be a feasible approach to improve the flame retardancy of fiber reinforced composites.

Mechanical and degradation properties of natural fiber reinforced PLA composites: Jute, sisal, and elephant grass

Abstract: An experimental study has been carried out to investigate and characterize the properties of elephant grass fiber reinforced fully biodegradable poly lactic acid (PLA) composites. The composites were prepared with various weight fractions of untreated and treated fibers in PLA matrix using injection moulding technique. The tensile strength of PLA composite with treated elephant grass at 20% fiber loading was 18.14% and 24% higher than that of treated jute/PLA composite and plain PLA, respectively. While the flexural strength of treated elephant grass/PLA composite at same fiber loading was 4% and 22% higher than that of treated sisal composite and plain PLA, respectively. The impact strength of composites with untreated elephant grass, sisal and jute fibers were 129.5%, 111.5% and 22.3%, respectively higher when compared with plain PLA. The water absorption rate increased in all the composites as the fiber content increased and the absorption rate reduced with successive alkali treatment on the fibers. The thermal stability of the composite had been reduced with successive alkali treatments as evident from the TGA analysis. The percentage weight loss in all the composites was linearly increasing with number of days of soil burial. The degradation was high in composite with untreated fibers at highest weight fraction. Using enzymatic environment, the degradation was much faster compared to soil burial. Significant effect of surface modification was evident during observing surface morphology of tensile fractured and soil degraded surfaces of the composites using SEM. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers

High-Performance Graphene-Based Natural Fiber Composites.

Abstract: Natural fiber composites are attracting significant interest due to their potential for replacing synthetic composites at lower cost with improved environmental sustainability. However, natural fiber composites suffer from poor mechanical and interfacial properties. Here, we report coating of graphene oxide (GO) and graphene flakes (G) onto natural jute fibers to improve mechanical and interfacial properties. The coating of graphene materials onto jute fibers enhanced interfacial shear strength by ∼236% and tensile strength by ∼96% more than untreated fibers by forming either bonding (GO) or mechanical interlocking (G) between fibers and graphene-based flakes. This could lead to manufacturing of high-performance and environmental friendly natural fiber composites that can potentially replace synthetic composites in numerous applications, such as the automotive industry, naval vessels, household products, and even in the aerospace industry.

Fique Fabric: A Promising Reinforcement for Polymer Composites

Abstract: A relatively unknown natural fiber extracted from the leaves of the fique plant, native of the South American Andes, has recently shown potential as reinforcement of polymer composites for engineering applications. Preliminary investigations indicated a promising substitute for synthetic fibers, competing with other well-known natural fibers. The fabric made from fique fibers have not yet been investigated as possible composite reinforcement. Therefore, in the present work a more thorough characterization of fique fabric as a reinforcement of composites with a polyester matrix was performed. Thermal mechanical properties of fique fabric composites were determined by dynamic mechanical analysis (DMA). The ballistic performance of plain woven fique fabric-reinforced polyester matrix composites was investigated as a second layer in a multilayered armor system (MAS). The results revealed a sensible improvement in thermal dynamic mechanical behavior. Both viscoelastic stiffness and glass transition temperature were increased with the amount of incorporated fique fabric. In terms of ballistic results, the fique fabric composites present a performance similar to that of the much stronger KevlarTM as an MAS second layer with the same thickness. A cost analysis indicated that armor vests with fique fabric composites as an MAS second layer would be 13 times less expensive than a similar creation made with Kevlar™.

The effects of chemical treatment on the structural and thermal, physical, and mechanical and morphological properties of roselle fiber‐reinforced vinyl ester composites

Abstract: Roselle fiber is a type of natural fiber that can potentially be used as a reinforcement material in polymer composites for different applications. This study investigated the chemical, physical, thermal, mechanical, and morphological characteristics of roselle fiber-reinforced vinyl ester subjected to different fiber treatments. The roselle fiber was treated with alkalization and a silane coupling agent, and samples were prepared using the hand lay-up method. Treated roselle fiber significantly enhanced most of the properties of vinyl ester biocomposites compared with an untreated biocomposite. The results revealed that alkalization and silane treatment of the fiber changed its chemical properties. The treated fiber improved water repellence behavior of the roselle fiber-reinforced vinyl ester compared with the untreated fiber. Use of a silane coupling agent was determined as the best chemical treatment for the water absorption effect. Thermogravimetric analysis (TGA) demonstrated that alkalization-treated fiber had improved thermal stability; however, the opposite result was obtained with the silane-treated fiber. The morphological examination of treated and untreated roselle fiber-reinforced vinyl esters showed a good fiber adhesion between the treated fiber and the matrix, and less fiber pull-out from the matrix was observed. This observation provides good indication of the interfacial interlocking between the fiber and the matrix, which improved the tensile properties of the composites. In contrast, the impact results revealed that the treated fiber had a decreased impact energy compared with the untreated fiber. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers

Influence of natural fibers characteristics on the interface mechanics with cement based matrices

Abstract: The use of Natural Fibers in cementitious composites is an innovative technical solution but, they are characterized by a complex microstructure and significant heterogeneity, which influence their interaction with cementitious matrices, whose identification requires further advances in the current state of knowledge. The present study summarizes the results of a wide series of pull-out tests carried out on sisal, curaua and jute fibers. Then, the experimental results are employed in an inverse identification procedure aimed at unveiling the key features of the aforementioned bond-slip laws. Morphological, chemical, physical and mechanical characterization of the natural fibers were correlated with the resulting bond properties within the embedding matrix. The obtained results in terms of relevant parameters, such as bond strength and fracture energy (under pull-out stresses) of the fiber-matrix interface, pave the way for future studies intended for a better understanding of the structural response of Natural Fiber Reinforced Cementitious Composites.

Effect of sodium bicarbonate treatment on mechanical properties of flax-reinforced epoxy composite materials

Abstract: This paper deals with the evaluation of the effect of an eco-friendly and cost-effective surface treatment based on the use of sodium bicarbonate on the mechanical properties of flax-reinforced epo...

Effects of water, alkali solution and temperature ageing on water absorption, morphology and mechanical properties of natural FRP composites: Plant-based jute vs. mineral-based basalt

Abstract: Because of the environmental, technical and economic benefits, plant-based (e.g. jute) natural and mineral-based (e.g. basalt) natural fiber reinforced polymer (FRP) composites are considered as alternatives for conventional glass FRP composites. However, the scarcity of data on the long-term durability of natural FRP composites becomes a major barrier for their wider use in different engineering areas. In this work, durability studies were performed to evaluate the effects of water and alkali solutions, and the temperature of their solutions on weight gain, tensile properties and surface morphology of jute and basalt fabric reinforced epoxy composites. In total, four types of composite specimens (i.e. untreated jute fabric/epoxy, alkali-treated jute fabric/epoxy, silane-treated jute fabric/epoxy and untreated basalt fiber/epoxy) were fabricated and exposed to different ageing conditions for 180 days. The water absorption and tensile properties of these four composite specimens were measured and compared. The results showed that in general, the weight gains of the three plant-based natural jute/epoxy specimens (i.e. from 5.0% to 8.5%) were larger than that of the mineral-based natural basalt/epoxy composite (i.e. from 1.1% to 2.2%). Both alkali and silane treatments of jute fiber reduced the water absorption and enhanced the tensile strength of the resulting jute fabric/epoxy composites. For all the four types of composites, increasing exposure temperature of the water and the alkali solutions caused the reduction in their tensile strength. The strength reduction of these four types of composites at alkali solution was larger than the reduction of the corresponding composite at the water solution. In addition, their reduction in tensile strength was more pronounced compared with that in their Young's modulus. Compared with mineral-based basalt/epoxy composites, the untreated, alkali-treated and the silane-treated plant-based jute fabric/epoxy composites showed higher tensile strength reduction retention for the considered ageing conditions. However, the basalt fiber composites had much higher modulus retention. The deterioration of the interfacial properties of these composites at different ageing conditions was confirmed by the SEM observations.

Investigations on the performances of treated jute/Kenaf hybrid natural fiber reinforced epoxy composite

Abstract: Natural fiber composite laminates are nowadays used in structural application such as aerospace, automobile and in sports goods because of their high strength to weight ratio and renewability. Hence the study of mechanical behaviors of natural fiber composites is very important in using these composite laminates for such specific applications. This project aims at identifying the mechanical properties of hybrid natural Jute/Kenaf fiber. The major drawbacks in natural fiber are its Resin incompatibility. Surface treatment of fiber is made to improve the interfacial bonding between the fiber and resin and to reduce the moisture absorption. Laminates are fabricated using Hand lay-up technique. Mechanical properties such as tensile, flexural, and Impact test for jute/kenaf hybrid laminates were obtained. Specimen preparation and Mechanical property testing were carried out as per ASTM standards. Micro structures of the different layer of hybrid specimens are scanned by the Scanning Electron Microscope.

Retting Process as a Pretreatment of Natural Fibers for the Development of Polymer Composites

Abstract: The development of high-performance materials made from natural resources is increasing worldwide. Within this framework, natural fiber reinforced polymeric composites now experience great expansion and applications in many fields, ranging from the automotive to the construction sector. The great challenge in producing composites containing natural fibers and with controlled features is connected to the great variation in properties and characteristics of fibers. The quality of the natural fibers is largely determined by the efficiency of the treatment process and can dramatically influence the properties of the final composites. The overall fiber extraction processes, applied to vegetable fibers, is called retting and consists in the separation of fiber bundles from the cuticularized epidermis and the woody core cells. Today, many efforts are being made to optimize the retting methods in terms of fiber quality production, reduction of environmental issues and production costs. This chapter aims to provide a classification and an overview of the retting procedures that have been developed during years and are applied to extract mainly bast fibers.

Mechanical, Dynamic Mechanical and Thermal Properties of Banana Fiber/Recycled High Density Polyethylene Biocomposites Filled with Flyash Cenospheres

Abstract: This study presents the preparation of Natural fiber-reinforced biocomposites based on Recycled High Density Polyethylene (RHDPE)/Banana Fiber (BF)/Fly ash Cenospheres (FACS) and aims to increase the economic value of these waste materials. Maleic anhydride grafted HDPE (MA-g-HDPE) was used as a compatibilizer to increase the dispersion of fibers into the polymer matrix as well as to increase the compatibility between the matrix and fillers. Variation in mechanical, thermal and dynamic mechanical properties with the addition of FACS in RHDPE/BF composites was investigated. It was observed that 7.5 wt% FACS, 30 wt% BF and 3 wt% MA-g-HDPE within RHDPE matrix resulted in an increase in tensile strength to 17%, tensile modulus to 188%, flexural strength to 38%, flexural modulus to 159% and hardness to 37% as compared with the RHDPE matrix. Significant enhancement in the thermal stability of the RHDPE/BF biocomposites was also observed in presence of FACS under thermogravimetric analysis. The morphology of the prepared biocomposites has been examined by using scanning electron microscopy. Dynamic mechanical analysis tests revealed an increase in storage and loss modulus of the biocomposite system. The use of such recycled material, agricultural and industrial wastes increased the properties of the final product suggesting their use to be a good alternative in the production of polymeric composites.

Extraction and investigation of lightweight and porous natural fiber from Conium maculatum as a potential reinforcement for composite materials in transportation

Abstract: The aim of the study is to evaluate the use of undervalued Conium maculatum plant fibersas a new potential for the reinforcement of composite materials. In this research, new natural cellulosic fibers were extracted from Conium maculatum plant using conventional water retting method. Mechanical strength, crystallography, thermal stability and chemical structure of Conium maculatumfibers were investigated by single fiber tensile testing, X-Ray Diffraction Analysis (XRD), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. Additionally, surface topography and surface chemistry were analyzed by Scanning Electron Microscope (SEM) and X-Ray Photoelectron Spectroscopy (XPS), respectively. SEM images revealed that the fiber has a porous structure which is very critical for the transportation industry. XPS results indicated that the fiber surface is hydrophobic which is very critical for the composites prepared with hydrophobic matrices like polyolefin materials. Chemical composition of the fibers was also determined. The main components of Conium maculatumfibers such as cellulose, hemicellulose and lignin were reported to be 49.5, 32.2 and 8.6%, respectively. The crystallinity index was stated as 46.4%. The fibers are thermally stable up to 260 °C. Tensile strength of Conium maculatum fibers were determined as 327.89 ± 67.41 MPa. This research paper suggests a novel sustainable ecological material for reinforcement in polymeric composites.

Experimental Investigation of the Physical and Mechanical Properties of Sisal Fiber-Reinforced Concrete

Abstract: Concrete is a very popular material in the construction industry—it is, however, susceptible to quasi-brittle failure and restricted energy absorption after yielding. The incorporation of short discrete fibers has shown great promise in addressing these shortfalls. A natural fiber such as sisal is renewable, cheap, and easily available. It has also exhibited good tensile strength and can significantly improve the performance of concrete. In this study, the physical and mechanical properties of sisal fiber-reinforced concrete were reported. Sisal fibers were added in the mix at percentages of 0.5%, 1.0%, 1.5%, and 2.0% by weight of cement. Physical properties measured are workability, water absorption, and density while mechanical properties reported are compression strength, split tensile strength, and static modulus of elasticity. The computed modulus of elasticity of sisal fiber-reinforced concrete was compared with predicted values in some common design codes. From the study, it was concluded that sisal fiber can enhance the split tensile strength and Young’s modulus of concrete but cannot improve its workability, water absorption, and compressive strength.

Finite element models of natural fibers and their composites: A review:

Abstract: Finite element method has been widely applied in modeling natural fibers and natural fiber reinforced composites. This paper is a comprehensive review of finite element models of natural fibers and...