Short Coir Fibers Research Articles

Assessment of mechanical and thermal properties of hybrid co-woven biofiber polymer composites

The recent research explores the hybridizing effect of inter and intra woven natural engineering fibers in epoxy composites. The inter and intra woven brown flax (Fb), white flax (Fw), and jute (J) fabrics have been comingled with short coir fibers (SCF). The composites are successfully made using the hand layup procedure, and the successive arrangement of fabrics is based on the tensile characteristics of inter and intra-woven fabrics. The physical, thermal, and mechanical characteristics of composites are experimentally studied. The C1 composite having (Fb+Fw)/Fw/J/J/Fw/(Fb+Fw) fabric sequence without filler demonstrated highest tensile strength of 30.15 MPa, elastic modulus of 2164.59 MPa, flexural strength of 66.46 MPa, and flexural modulus of 3900.74 MPa. However, the C3 composite containing SCF filler, having a similar fabric sequence as that of C1 demonstrated highest impact strength of 116.52 KJ/m2. Thermogravimetric analysis (TGA) revealed that the composite C3 exhibited better thermal stability than other hybrid patterns. Fourier transform infrared (FTIR) spectroscopy study confirmed the interaction of hydrogen bonds with different polymers, matrices, and fillers. Further, microstructural and fractography analysis have been done to analyze the surface phenomena of the composites and mechanical failure analysis.

Influence of nano industrial waste and short coir fiber filler on hybrid inter and intra yarn bio fiber composites

Bio-polymer composites are emerging as a feasible substitute for conventional polymers in various major fields of applications. In the current research, the impact of hybridization of inter and intra-woven natural engineering fibers namely, brown flax, white flax, and jute of different amalgamations along with commingled SCF and novel nano IW filler has been studied. The composites are manufactured by hand layup process and physical and thermomechanical characteristics of the composites are experimentally studied. The composites mingled with IW filler demonstrated better dimensional stability and mechanical properties such as maximum tensile strength of 36.74 MPa, bending strength of 82.53 MPa, and hardness of 84.89 D compared to other composites. However, elastic and flexural modulus are maximum for composite without any filler. The composites mingled with SCF filler demonstrated the highest impact strength, energy absorption, and elongation. Thermogravimetric analysis and thermal conductivity study demonstrated that the composite with SCF filler exhibited better thermal stability and thermal resistance than the other hybrid composites. Fourier transform infrared spectroscopy study confirms the interaction of hydrogen bonds with different polymers, matrices, and fillers. It is established that the weaving pattern and the filler types greatly influences the mechanical and thermal characteristics of the composites. Filler addition and fabric hybridization optimizes the catastrophic failures and enhances the thermal stability, hence becoming more suitable for small interior structural components in aerospace and automobile applications.

Effects of Physical and Mechanical Properties of Coir Fiber and Reinforced Epoxy Composites Treated with Acetic Anhydride and Alkali

ABSTRACT Modified coir fiber improves compatibility between fiber and matrix. To explore a better fiber treatment approach and enhance the mechanical properties of composites, this study conducted alkali treatment and acetic anhydride treatment on long and short coir fibers. The effects of different treatments on the properties of coir fibers were characterized using TGA, FTIR, SEM, and stereomicroscopy, and the mechanical properties of the composites were tested. Results showed that the tensile strength of alkali-treated coir fibers (ACF) and acetic anhydride-treated coir fibers (AACF) were remarkably improved. Notably, ACF exhibited a significant 69% increase in tensile strength. The tensile strength of composites with alkali-treated long coir fibers (ALC) and composites with alkali-treated short coir fibers (ASC) reached 34.51 and 21.14 MPa, respectively. The highest flexural strength was found for the acetic anhydride-treated coir fibers, and the flexural strength of composites with acetic anhydride-treated long coir fibers (AALC) and composites with acetic anhydride-treated short coir fibers (AASC) reached 54.38 and 53.46 MPa, respectively. This study presents an improved methodology for enhancing the interfacial bonding ability between coir fibers and the matrix, consequently improving the properties of composites. It offers reference for the investigation of natural fiber composites.

The Influence of Short Coir, Glass and Carbon Fibers on the Properties of Composites with Geopolymer Matrix.

The aim of the article is to analyze the influence of short coir, glass and carbon fiber admixture on the mechanical properties of fly ash-based geopolymer, such as: flexural and compressive strength. Glass fiber and carbon fibers have been chosen due to their high mechanical properties. Natural fibers have been chosen because of their mechanical properties as well as for the sake of comparison between their properties and the properties of the artificial ones. Fourth series of fly ash-based geopolymers for each fiber was cast: 1, 2, and 5% by weight of fly ash and one control series without any fibers. Each series of samples were tested on flexural and compressive strength after 7, 14, and 28 days. Additionally, microstructural analysis was carried out after 28 days. The results have shown an increase in compressive strength for composites with fibers—an improvement in properties between 25.0% and 56.5% depending on the type and amount of fiber added. For bending strength, a clear increase in the strength value is visible for composites with 1 and 2% carbon fibers (62.4% and 115.6%). A slight increase in flexural strength also occurred for 1% addition of glass fiber (4.5%) and 2% addition of coconut fibers (5.4%). For the 2% addition of glass fibers, the flexural strength value did not change compared to the value obtained for the matrix material. For the remaining fiber additions, i.e., 5% glass fiber as well as 1 and 5% coconut fibers, the flexural strength values deteriorated. The results of the research are discussed in a comparative context and the properties of the obtained composites are juxtaposed with the properties of the standard materials used in the construction industry.

Preparation of chemically functionalized and self compatibilized short coir fiber ‐ high density polyethylene composites

AbstractThe interphase adhesion plays key role in the performance of composites. The commonly employed strategies include blending with an external compatibilizer or utilizing chemical grafting followed by purification and copolymerization. Here, we showcase a reformed and simple approach in the fabrication of chemically functionalized, self compatibilized composites [PE‐TCF5%‐MA2%] by insitu grafting of maleic anhydride in the polymer melt, followed by the reactive compatibilization of treated short coir fiber. Micro‐structural analysis of the composites revealed enhanced fiber/matrix adhesion. The improved mechanical, viscoelastic, and thermal properties of composites can be attributed to new interfacial bond formed, which was confirmed by Fourier transform infrared [FTIR] studies. PE‐TCF5%‐MA2% exhibited approximately 74% and 25% improvement in tensile strength compared to untreated (PE‐UCF) and treated (PE‐TCF) fiber composites respectively. Dynamic mechanical analysis of composites displayed similar trend with highest value of storage modulus recorded for PE‐TCF5%‐MA2%. Final decomposition temperature of all composites was shifted to higher side. Peak degradation temperature was increased with a marginal increase of residual char. Together with the goodness of agro‐based fiber and feasiblity of this low cost method suggests the potential of PE‐TCF‐MA toward bulk industrial prodution of composite panels.

Injection molding of short coir fiber polypropylene biocomposites: Prediction of the mold filling phase

The mold‐filling phase in injection molding is the most important one because the material flow behavior controls the final part structure. In this work, the effect of melt rheology on the flow front progression of coir fiber (2.5, 5, 10, and 15 wt%) filled polypropylene is investigated. The flow behavior is predicted using the incompressible Navier–Stokes equations to determine the flow front shape and position and the model proposed is in good agreement with the experimental results for the range of conditions studied. Finally, to provide a better understanding of the effect of different processing conditions (pressure, melt, and mold temperature) on the flow front evolution, several simulations were performed using Autodesk Moldflow Insight. POLYM. COMPOS., 40:4042–4055, 2019. © 2019 Society of Plastics Engineers

PP-coir Composites (PPCC): Fabrication and Study of Flexural Properties

Today we are more concern about the environment. Synthetic polymers are the most responsible pollutant for environmental pollution. Good replacing agents for the synthetic polymers are the natural polymer. That is why the uses of natural fiber reinforced composites are increasing day-by-day. In this research natural polymer coir fiber was used as the reinforcing agent with the synthetic polymer polypropylene. PP-coir composites were fabricated using a simple hot press molding method. The prepared composites were characterized by the density, tensile, and flexural properties. The effect of fiber addition on some physical and mechanical properties was evaluated. The density increases with the increase of fiber addition. The tensile strength of fabricated product increases with the increase of fiber addition up to 10% (wt.) and then decreases continuously. The elongation of fabricated product decreases with the increase of fiber addition continuously. The changes in the mechanical properties were broadly related to the accompanying interfacial bonding of PP- coir composites (PPCC). It revealed that the introduction of short coir fiber led to a slightly improved thermo oxidative stability of PP- Coir composites. The flexural strain of fabricated product decreases continuously with the increase of fiber addition. But here untreated fiber reinforced composites show higher strain than that of treated fiber reinforced composites.

HDPE- Coir composites–fabrication, process parameters and properties

The composites of biodegradable high density polypropylene (HDPE) reinforced with short coir fiber were prepared by melt mixing followed by hot press molding. The effect of fiber addition on some physical and mechanical properties was evaluated. Different process parameters (e.g. mixing time, heating temperature and time, cooling time etc.) were established for good sample preparation The effects of fiber addition on some physical and mechanical properties were evaluated. The mechanical properties were studied via Universal Testing Machine (UTM). The density was increased with the increase of fiber addition. The tensile strength (TS) of fabricated product increased with the increase of fiber addition up to 10% (by wt.) and then decreased continuously. The elongation of fabricated composites was decreased with the increase of fiber addition continuously. The changes in the mechanical properties were broadly related to the accompanying interfacial bonding of HDPE coir composites (HDPECC). To observe the hydrophilicity of the prepared composites was evaluated by the water uptake properties. The interfacial bonding of the fiber and matrix of the coir fiber reinforced composites was studied via scanning electron microscope. It revealed that the introduction of short coir fiber led to a slightly improved mechanical stability of PP- Coir composites.

Mechanical properties prediction of polypropylene/short coir fibers composites using a self‐consistent approach

Short coir fibers composite of thermoplastic polypropylene (PP) matrix was successfully prepared by using a twin‐screw extruder and an injection molding machine. In order to provide a better understanding of the effect of fiber orientation and concentration (2.5, 5, and 10 wt%) on the mechanical properties of short coir fibers reinforced PP, a self‐consistent approach was developed based on a modified Hirsch model by taking the empirical parameter (x) proportionally to the fiber orientation factor (α). Finally, the results are compared with other models (Hirsch and Tsai‐Pagano) and validated with experimental data. Overall, our approach was found to better predict the mechanical results in terms of Young's modulus, tensile strength and torsion modulus. POLYM. COMPOS., 40:1919–1929, 2019. © 2018 Society of Plastics Engineers

Surface lignin removal on coir fibers by plasma treatment for improved adhesion in thermoplastic starch composites

The high lignin to cellulose ratio of coir fibers results in low compatibility between these fibers and natural polymers like starch, leading to poor mechanical properties in the composites. Plasma treatment using either air or oxygen proved to be an effective in removing the lignin rich amorphous layer on coir fibers, as it was clearly observed by SEM. The ratio of the FTIR signal related to lignin (1508cm−1) and cellulose (1317cm−1) decreases 10 times for air plasma treated fibers and 20 times for oxygen plasma treated samples. Composites of plasma treated short coir fibers and thermoplastic starch presented considerable increase in mechanical properties in comparison to composites made with untreated fibers. Tensile strength increased by up to 300% and elastic modulus improved by a factor of nearly 20 times, which was associated with enhanced fiber-matrix adhesion after plasma treatment with oxygen for 7.2min at 80W power.

Mechanical and Thermal Properties of PLA Biocomposites Reinforced by Coir Fibers

In this work, polylactic acid (PLA) biocomposites reinforced with short coir fibers were fabricated using a corotating twin-screw extruder and injection molding machine. Short coir fibers were treated by mixed solution including hydrogen peroxide and sodium hydroxide to improve the adhesion between fibers and PLA matrix. The effects of treated coir fiber content (1, 3, 5, and 7 wt%) on tensile, impact, thermal properties, and surface morphology of PLA biocomposites were investigated. The best impact strength results were obtained for 3 wt% PLA/treated coir fiber biocomposites, where the impact strength was increased by approximately 28% compared to the neat PLA. The tensile modulus of PLA biocomposites was increased by increasing the treated coir fiber content. These results were confirmed by morphological structure analysis. Differential scanning calorimetry (DSC) results demonstrated a minor effect of the treated coir fiber on thermal behavior of PLA resin. Thermogravimetry analysis (TGA) demonstrated that the thermal stability of the PLA/treated coir fiber biocomposites was reduced by the incorporation of treated coir fiber.

Mechanical Properties of Coir/ G Lass Fiber Epoxy Resin Hybrid Composite

Sustainable development and environmental awareness directed researcher to focus on naturally occurring resources. Leading to this there is a growing trend for usage and experimenting on Natural fiber reinforced polymer composites. Fiber reinforced polymer composites shows many qualities which include low weight, easy manufacturability, biodegradability, high strength to weight ratio, low cost of production etc. Though natural fiber possesses good properties yet their affinity towards water and improper matrix interface bonding are major concern. Due to these challenge strength of composite is considerably affected. Uses of synthetic fibers do not impose any challenge as the natural fibers, but they are non-biodegradable and cost more than natural fiber. In present work properties of both synthetic and natural fibers are utilized in a way to improve the mechanical properties. For this purpose, naturally occurring coir fiber and synthetic glass fiber mats are used as reinforcement while thermosetting polymeric resin Epoxy is used as matrix material. To decrease moisture absorption behaviour of coir fiber, it is chemically treated with Sodium hydroxide. This chemical treatment reduces the affinity of fiber towards material and increases surface roughness thus results in better matrix reinforcement interface bonding. Short coir fiber /glass fiber mat hybrid composite is fabricated by hand-layup method. The study confirms that the mechanical properties of the composites are varies with volume fraction and fiber length of the fibers.

Effect of Chitosan Particle Addition on the Tensile and Flexural Strength of Coir Fiber Reinforced Polyester Composites

The influence of chitosan impregnation on the tensile and flexural strength of the short coir fiber reinforced polyester composites were studied in this investigation. The chitosan fillers were dispersed in polyester matrix, and laminates were prepared by reinforcing coir fibers in chitosan –polyester matrix. The composites were fabricated by varying filler content, fiber content and fiber length in three levels and their influence on tensile and flexural strength of the composites were studied. The composites with fiber length 30 mm, filler content 4% and fiber content 25% showed better values tensile (23 MPa) and at the same time the flexural strength (28MPa) of the composite was observed to be better with fiber length 30 mm, filler content 4 % and fiber content 25%.

Mathematical Modeling and Optimization of Mechanical Properties of Short Coir Fiber-Reinforced Vinyl Ester Composite Using Genetic Algorithm Method

The tensile, flexural, and impact properties of coir-fiber reinforced vinyl ester composites were evaluated. The short coir fibers with different proportions in fiber length and fiber content were used as reinforcements in polymer-based matrices. The mathematical models of tensile, flexural, and impact properties were developed using statistical packages and optimized using the genetic algorithm method to find the optimum fiber parameters for maximum value of mechanical properties.

STUDIES ON EFFECTS OF SHORT COIR FIBER REINFORCEMENT ON FLEXURAL PRPPERTIES OF POLYMER MATRIX

For environmental concern on synthetic fibers (such as glass, carbon, ceramics etc) natural fibers such as sisal, flax, hemp, jute, kenaf, coir etc., are widely used. In this research work, short coir fibers reinforced polymer composite have been developed by hand layup techniques with varying fiber percentages (5%, 10%, 15%, 20%, 25% by weight). The developed coir fiber reinforced composites were then tested for their FLEXTURAL properties. The result shows that a flexural property increases with increases in fiber percentage; however after a certain fiber weight percentage the properties are decreased. From the data of tested results conclude that 20% of coir reinforcement at 4mm thickness of polymer composite exhibited higher percentage of elongation. The coir fiber in the present study could be used as an effective reinforcement for making composites, which have an added advantage of being light weight

Interfacial, Mechanical and Thermal Properties of Coir Fiber-Reinforced Poly(Lactic Acid) Biodegradable Composites

The poly(lactic acid) (PLA) biodegradable composites reinforced with short coir fibers were developed and studied. The effect of fiber mass content varying from 10 to 50% on mechanical and thermal properties of coir/PLA composites have been studied in terms of tensile properties, thermal stability and thermal expansion.The effect of alkali treatment on interfacial shear strength (IFSS), mechanical and thermal properties of coir/PLA composites was investigated. The coir fibers which are soaked in 5% sodium hydroxide solution at room temperature for 72 h showed the highest IFSS at 72.8% higher than untreated coir fibers. Alkali treatment of coir fibers enhanced the tensile properties of coir/PLA composites. The best tensile strength of coir/PLA composite was achieved at fiber mass content of 20% in this study. Below about 370°C, the coir/PLA biodegradable composites are found to have much higher thermal stability compared to coir fiber, but lower than that of PLA resin. Alkali-treated coir/PLA composites having improved fiber–matrix adhesion resulted in stable composites with better thermal stability than untreated coir/PLA composites. The thermomechanical stability of PLA resin is significantly improved by the addition of reinforcing coir fibers.The fractured surface morphology of the composite specimens exhibited an improvement of interfacial fiber–matrix adhesion in the composites reinforced with alkali-treated coir fibers.

Degradation Studies of Coir Fiber/Polyester and Glass Fiber/Polyester Composites under Different Conditions

The influence of different conditions on the mechanical properties of short coir fiber reinforced polymer composites as well as glass fiber reinforced polymer composites have been analyzed and compared. Fiber length of 20 mm was found to be optimum for the best result. It is observed that the filler loading of 30 phr was most suitable for best results. Degradation studies were carried out in different solvents like 10% NaOH, 1 N HCl, and 10% NaCl and water. The effect of these solvents and water on the mechanical properties of the composites was studied in detail. The deterioration of mechanical properties of the coir/PE and glass/PE composites by environmental weathering was also studied.

Dynamic mechanical behavior of short coir fiber reinforced natural rubber composites

Dynamic mechanical behavior of natural rubber and its composites reinforced with short coir fibers has been studied. Maxima in tan δ, E″ and the middle point of E′ vs. temperature curves of the gum natural rubber compound at different frequencies almost coincide with one another. But the maxima in tan δ and E″ do not coincide in the case of composites. It is observed that as frequency increases the values of tan δ and E″ decrease whereas the values of E′ increase in the case of both gum and the composites. The values of E″ and tan δ increase with fiber incorporation, which indicates lower heat dissipation in the gum. Two prominent peaks are observed in the tan δ vs. temperature curve of these composites due to the dynamic mechanical behavior of matrix and fiber. The additional small peak represents the dynamic mechanical behavior at the interface. The effect of chemical treatment of coir fiber on damping of composites was studied and it was found that composite with poor interfacial bonding tend to dissipate more energy than that with good interfacial bonding.

Tensile stress relaxation of short‐coir‐fiber‐reinforced natural rubber composites

AbstractThe stress relaxation behavior of natural rubber (NR) and its composites reinforced with short coir fibers under tension was analyzed. The rate of stress relaxation was a measure of the increase in the entropy of the compounds: the higher the rate was, the greater the entropy was. At lower strain levels, the relaxation mechanism of NR was independent of strain level. However, the rate of relaxation increased with the strain level. Also, the strain level influenced the rate of stress relaxation considerably in the coir‐reinforced NR composites. However, the relaxation mechanisms of both the unfilled compound and the composite were influenced by the strain rate. The rate of relaxation was influenced by fiber loading and fiber orientation. From the rate of stress relaxation, we found that fiber–rubber adhesion was best in the composite containing fibers subjected to a chemical treatment with alkali, toluene diisocyanate, and NR solutions along with a hexaresorcinol system as a bonding agent. In this study, the stress relaxation curves could not be viewed as segments with varying slopes; however, a multitude of inflection points were observed on the curves. Hence, we propose neither a two‐step nor three‐step mechanism for the coir‐fiber‐reinforced NR composites as reported for some other systems. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 96–104, 2004

Melt Flow Behavior of Short Coir Fiber Reinforced Natural Rubber Composites

Abstract The melt flow behavior of natural rubber composites containing untreated, acetylated and gamma ray irradiated coir fibers was studied using an Instron Capillary Rheometer. Coir fibers of length 10 mm were used at different loading, viz., 5, 10, 20 and 30 phr. The dependence of melt viscosity, flow behavior index (n′) and extrudate deformation of the composites with shear rate, shear stress and loading of fibers was analyzed. The pseudoplasticity of the melt increased with fiber loading. At low level of fiber loading, the compound exhibited increased viscosity but at high fiber loading the compound showed low viscosity. This may be attributed to the formation of a sheath-core structure at high loading where fiber is concentrated at the core of the extrudate. Incorporation of fibers decreased the extrudate deformation and die swell and this improvement was more prominent at higher fiber loading.