Optimum Fiber Loading Research Articles

Polyvinyl Chloride Reinforced with Areca Sheath Fiber Composites—An Experimental Study

ABSTRACTThis research work deals with fibrous composites obtained by using treated and untreated areca sheath (AS) fibers reinforced in polyvinyl chloride (PVC) by injection molding process. Surface treatments of fibers have been carried out to have a better compatibility with PVC matrix. The tensile and flexural strength have been found to increase at the early stage with the increase in treated areca fiber content till optimum (18 wt% of fiber) fiber loading thereafter declines. At optimum fiber loading, the tensile strength, flexural strength and young’s modulus values are 42.38 MPa, 18.22 MPa and 2.38 GPa, respectively, which give maximum values in comparison to other fiber loadings. Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), biodegradability tests and scanning electron microscopy (SEM) have been used for analysis. The TGA inferred that the thermal stability of the composites increased as compared to neat PVC matrix. Further, the composites exhibit excellent biodegradability property and their biodegradability increases with the increase of areca fiber content. From the properties obtained at optimum fiber loading (18 wt% of fiber), the composite can be suitable for automotive dashboard and door panel applications.

The performance of mengkuang leaf fiber reinforced low density polyethylene composites

The performance of mengkuang leaf fiber (MLF) reinforced low density polyethylene (LDPE) composites with different fiber volume and different mesh sizes were studied. The fibre weight percentage used in the research were 10%, 20%, and 30% and for different fiber size were <0.5 mm, 0.5-1 mm, and 1-2 mm. The extrusion and hot compression molding were used to fabricate the specimen testing. The mechanical testing performed were impact and flexural test which follows the ASTM standards D790-10 and Izod D256. It was observed that by increasing the fiber volume and fiber size, the flexural strength and the flexural modulus were increased. However the impact strength shows different results for fiber length and fibre content where the impact strength increases with fibre length but decreases with the increase of fiber content. It can be concluded that the 30% fibre content is the optimum fibre loading for the MLFLDPE composite with the flexural strength of 12.31 MPa, flexural modulus of 378.88 MPa and impact strength of 589.86 J/m whereby the 1.0-2.0 mm fibre length is the best fibre size for the MLF-LDPE composite with the flexural strength of 12.86 MPa, flexural modulus of 267.76 MPa and impact strength of 1511.57 J/m. In future studies fibres should undergo surface modification to increase the available surface area for reaction to increase the strength of the composite by better mechanical interlocking.

Study of Mechanical, Thermal, and Rheological Properties of Areca Fiber-Reinforced Polyvinyl Alcohol Composite

ABSTRACTIn the present work, polyvinyl alcohol (PVA) thermoplastic matrix has been reinforced by randomly oriented short areca sheath (AS) fiber to prepare PVA/AS composite by injection molding. The fiber has been chemically modified with benzyl chloride to have better compatibility with PVA matrix. Different mechanical properties such as tensile strength, Young’s modulus, flexural strength, flexural modulus, and impact strengths of the composite with varying weight percentage of treated fibers have been studied and the optimum weight percentage has been determined by regression analysis. It has been observed that the maximum values of mechanical properties of the composite are obtained at optimum weight percentage (i.e., 27 wt%) of AS fiber. The chemical interaction of polymers with fibers has been characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy at this fiber loading. The thermal properties of the composite have been studied through dynamic mechanical thermal analysis, thermal gravimetric analysis, and differential scanning calorimetry at optimum fiber loading. Rheological properties of the composite in terms of complex viscosity (η*), storage modulus (G′), loss modulus (G″), and damping factor (tan δ) have been investigated through a parallel plate rheometer and compared with virgin PVA. From the characterization and study of properties, it is observed that PVA/AS composite gives best performance at optimum fiber loading.

Effects of Aspect Ratio and Loading on the Mechanical Properties of Prosopis Juliflora Fibre-reinforced Phenol Formaldehyde Composites

In this paper, an attempt was made to use Prosopis juliflora fibres (PJFs) as a reinforcing agent for phenol formaldehyde (PF) composites. Mechanical properties of the composites were studied for various fibre aspect ratios (FAR) and fibre loadings (FL). A scanning electron microscope (SEM) was used to study the fractured surface of the composites. The peak range of mechanical properties was identified for composites with a FAR of 136 and fibre loading of 23.53 wt%. This study shows that the optimum FAR and fibre loading for PJFs were found to be 136 and 23.53 wt% in order to achieve good reinforcement with better mechanical properties in the PF resin matrix. Experimental results were observed to be in very good agreement with the theoretical.

Kenaf/PP and EFB/PP: Effect of fibre loading on the mechanical properties of polypropylene composites

Kenaf and empty fruit bunch (EFB) fibre which are the important natural fibres in Malaysia were studied as nonwoven polymer composites. The effect of fibre loading on kenaf polypropylene and EFB polypropylene nonwoven composite was studied at different mixture ratio. Kenaf polypropylene nonwoven composite (KPNC) and EFB polypropylene nonwoven composite (EPNC) were prepared by carding and needle-punching techniques, followed by a compression moulding at 6 mm thickness. This study was conducted to identify the optimum fibre loading of nonwoven polypropylene composite and their effect on the mechanical strength. The study was designed at 40%, 50%, 60% and 70% of fibre content in nonwoven mat and composite. The tensile strength, flexural strength and compression strength were tested to evaluate the composite mechanical properties. It was found that the mechanical properties for both kenaf and EFB nonwoven composites were influenced by the fibre content. KPNC showed higher mechanical strength than EPNC. The highest flexural strength was obtained at 60% KPNC and the lowest value was showed by 40% EPNC. The tensile and flexural strength for both KPNC and EPNC decreased after the fibre loading of 60%.

Mechanical Properties of Randomly Oriented Calotropis Gigantea Fiber-Reinforced Phenol Formaldehyde Biocomposites

Mechanical properties such as tensile, flexural and impact, of randomly oriented Calotropis Gigantea Fiber (CGF) -reinforced Phenol Formaldehyde (PF) biocomposites were studied based on the five different fiber loadings (10, 20, 30, 40, and 50 vol%) and three different fiber lengths (3, 9, and 15 mm). The critical fiber length and optimum fiber loading were identified with the maximum level of mechanical properties in this composite. The fractured surfaces of composites after testing were studied by scanning electron microscope (SEM). The results revealed that the addition of CGFs is improving the mechanical properties of the PF composite. The properties of composites reach the properties of the neat resin sample at 20 vol% of all the cases. The critical fiber length and the optimum fiber loading to obtain the maximum mechanical properties were identified as 9 mm and 40 vol% respectively. Experimental tensile property values were compared with theoretical values and found to be in good agreement.

Experimental investigation on surface characterization of chemical treated Natural fiber composite

In this research work removal of lignin and hemicelluloses for untreated coir fiber reinforced composites was accomplished by suitable chemical treatment namely new method at optimum fiber loading such as 25% and 30%. To avoid the problem of untreated coir fiber, chemical treatment was done. Final treated fiber extraction process was gone through new method. It results in treated cellulose composite at 25% and 30% lignin and hemicelluloses was found to be decreased was revealed in Fourier transform infrared spectroscopy analysis, it shows defibrillation, de-polymerization in treated composite was revealed in scanning electron microscopy analysis, and shows high oxygen content percentage than carbon content percentage about 22.06% which demonstrates removal of lignin in treated composite, was revealed in element detection analysis.. The main objective was accomplished by the removal of lignin and hemicelluloses of natural fiber through suitable chemical treatment and at optimum fiber loading

Mechanical properties of novel kenaf short fiber reinforced bulk molding compounds (BMC)

Natural fibre composites have garnered a large following in the recent years due to their low density, commercially viability, no health risk, high specific strength and modulus and renewability. There have been many attempts to use the NFRC in automotive and other practical applications. This article discusses the mechanical properties mainly the tensile flexural and Izod impact strength of a recently developed kenaf-reinforced bulk moulding compound with unsaturated polyester matrix. It has been found that the tensile and flexural properties decline after the optimum fibre loading of 20% has been achieved for all fibre length. The highest was the BMC reinforced with 12-mm kenaf short fibre with 31.71 MPa and 15 mm with 266.21 MPa for tensile and flexural strength, respectively. It has also been found that the impact strength increases proportionally to the loading of the fibre due to the fibre being the stress transferring medium. It can be concluded that both fibre loading and fibre length plays a significant part in the mechanical properties of composites.

Tribological behavior of three‐dimensional braided carbon fiber reinforced polyetheretherketone composites

Three‐dimensional (3D) braided carbon fiber reinforced polyetheretherketone (denoted as CF3D/PEEK) composites with various fiber volume fractions were prepared via hybrid woven plus vacuum heat‐pressing technology and their tribological behaviors against steel counterpart with different normal loads at dry sliding were investigated. Contrast tribological tests with different lubricants (deionized water and sea water) and counterparts made from different materials (epoxy resin, PEEK) were also conducted. The results showed that the incorporation of 3D braided carbon fiber can greatly improve the tribological properties of PEEK over a certain range of carbon fiber volume fraction (Vf) and an optimum fiber loading of ∼54% exists. The friction coefficient of the CF3D/PEEK composites decreased from 0.195 to 0.173, while the specific wear rate increased from 1.48 × 10−7 to 1.78 × 10−7 mm3 Nm−1 with the normal load increasing from 50 to 150 N. Abrasive mechanism was dominated when the composites sliding with GCr15 steel counterpart under dry and aqueous lubrication conditions. Deionized water and sea water lubricants both significantly reduced the wear of the CF3D/PEEK composites. When sliding with neat PEEK counterpart, the CF3D/PEEK composites possess lower friction coefficient than those against epoxy resin and GCr15 steel counterparts. In general, CF3D/PEEK composites possess excellent tribological properties and comprehensive mechanical performance, which makes it become a potential candidate for special heat‐resisting tribological components. POLYM. COMPOS., 36:2174–2183, 2015. © 2014 Society of Plastics Engineers

Tribological Behavior of Acrylic Acid–Modified Date Palm Leaf–Reinforced Polyvinyl Alcohol Composite

Most machine components are frequently exposed to tribological loadings during their service life. Hence, the tribological performance of materials is an essential element to be considered in the design of mechanical parts in addition to mechanical properties. Previously, authors have studied the mechanical properties of date palm leaf–reinforced polyvinyl alcohol composite. In the present investigation, an attempt has been made to investigate the tribological behavior of the composite under a multipass abrasion condition. The composite was prepared by reinforcing randomly oriented acrylic acid–modified date palm leaf fibers with varying weight percentages of 10, 20, 28, and 30%. The performances of the specific wear rate and wear weight loss were investigated as a function of applied loads and abrading distances. It was observed that 28 wt% is the optimum fiber loading to achieve maximum tribological properties similar to mechanical properties obtained from previous work. Scanning electron microscopy was used to understand the wear mechanisms of the composite at optimum fiber loading.

Surface Treatment of Rubber Toughened Polyester Filled Carbon Black and Kenaf Hybrid Composite

The influences of surface treatment on kenaf fibre for rubber toughened polyester filled carbon black (CB) and kenaf hybrid composite were investigated, in consideration for applications such as automotive parts and integrated circuits (IC) encapsulations. Kenaf fibres were divided into treated and untreated fibres, where 6% of NaOH solution was used as the treatment solution. Unsaturated polyester was mixed with 3% liquid natural rubber (LNR) as toughening agent and 4% of CB, before hybridised with both treated and untreated kenaf that were varied from 5, 10, 15, 20 and 25% using mechanical stirrer and moulded by using hot compression technique. Flexural and impact testing were conducted and it was found that the hybridisation of CB and treated kenaf fibres composite showed improvement on flexural properties compared to non-hybrid CB filled composites although there are slight decrement on impact toughness. The optimum fibre loading for both treated and untreated kenaf were found at 25%.

Study on Cure Characteristics and Mechanical Behaviours of Kenaf Fibre Reinforced Natural Rubber Composites

In recent years, natural fibres appear to be as an outstanding material to substitute the conventional reinforcement materials in polymer composites. Kenaf fibre reinforced natural rubber (KFNR) composite was prepared by incorporating of different loadings of kenaf fibre using two roll mill machines. The compound was vulcanised at 150°C according to their respective cure time. The intention of this study is to investigate the influence of kenaf fibre on cure characteristics and mechanical bahaviour of (KFNR) composites.The result showed that the higher fibre content in composites led to shorter optimum cure time, t90. It was also observed that the tensile strength and elongation at break gradually decreased with an increment in fibre loadings. However, the trend was not similar for the hardness where the hardness value was increased by the increment of fibre loadings. The study has exhibited that the optimum fibre loading for the best performance of the composite achieved was 10 phr. The Scanning Electron Microscopy micrograph clarified that fibre dispersion and adhesion were weak thus resulting low in tensile strength and elongation at break.

Characterization of Laccase-Treated Kenaf Fibre Reinforced Recycled Polypropylene Composites

Raw and laccase-treated kenaf fibre (KF) were used individually to reinforce recycled polypropylene (RPP) using extrusion and injection moulding. Laccase was used to modify the surface of the fibre to improve the compatibility between fibre and matrix. Enzyme concentration and soaking time were considered as the treatment parameters. Maleic anhydride grafted polypropylene (MAPP) was used with a ratio of 1:10 as coupling agent to fibre. Fibres were characterized by density, energy dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), whereas composites were characterized by density, melt flow index (MFI), mechanical tests (tensile, flexural, and impact), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), field emission electron microscopy (FE-SEM), and water uptake analysis. Density, O/C ratio, and crystallinity of the treated fibre were increased. An optimum fibre loading of 40% gave the highest tensile properties. Tensile strength improved due to coupling agent by 37%, whereas treatment of fibre did the same by 40%. Flexural, impact, and thermal properties of the composites and crystallinity of the matrix were improved due to treatment. Morphological images of the composites showed better adhesion, and moisture absorption was reduced by 37% due to treatment and use of coupling agent.

Compatibilized PP/EPDM-Kenaf Fibre Composite Using Melt Blending Method

Thermoplastic Elastomer (TPE) composite reinforced with Hibiscus cannabinus, L fiber (kenaf fiber, KF) was prepared via melt blending method using internal mixer at temperature 180°C, screw rotational speed at 40rpm for 10 min. TPE matrix is a blend of polypropylene (PP) and ethylene-propylene-diene monomer (EPDM) at a ratio of 70:30. The optimum fiber loading were investigated from 0% to 20% by volume. The effect of coupling agent maleic anhydride polypropylene (MAPP) on the TPE composite has been investigated. The result shown that, with increasing the kenaf fiber content gradually increased the tensile strength and flexural strength for both treated and untreated PP/EPDM-KF composite. However, at 20% of kenaf fiber loading, it showed decreasing in impact strength due to brittleness of the samples. From the scanning electron micrograph (SEM) it has shown that the composite, with compatibilizer promotes better interaction between TPE and kenaf fiber.

Poly(Lactic Acid) (PLA)-reinforced Kenaf Bast Fiber Composites: The Effect of Triacetin

In this article, the mechanical, morphological, and dynamic-mechanical properties of the blends of PLA and kenaf bast short fiber were investigated. The composites, with different fiber loading and triacetin content, were prepared by melt blending techniques using a Brabender internal mixer at 60 rpm and 170°C for 10 min and their properties were examined. Pure PLA was used as a reference for the biocomposite samples. Triacetin was used as a plasticizer for PLA and PLA/kenaf composites in order to study the improvement in tensile properties. The tensile strength and stiffness of unplasticized biocomposite materials decreased with the addition of kenaf bast fibers but improved with the addition of triacetin. The optimum fiber loading was 30 wt% kenaf fibers in the PLA matrix with the addition of 5% triacetin. The dynamic mechanical analyses showed that triacetin improved the thermal stability of the biocomposites. The triacetin increased the storage modulus and gave a lower softening temperature for plasticized biocomposites. The micrographs of the tensile specimens and their fractured surfaces, which were examined by scanning electron microscopy, demonstrated that better adhesion between the fibers and the matrix was achieved with the addition of the plasticizer.

Effect of Chemical Modification on the Mechanical and Electrical Properties of Banana Fiber Polyester Composites

Banana fiber obtained from the sheath of the banana plant, Musa sapientum, has been used in the preparation of composites with polyester matrix. The effect of fiber loading on the dielectric constant, volume resistivity, and dielectric loss factor of the composites were determined with special reference to the effect of frequency. The fibers were modified chemically in order to have better compatibility with the matrix. The surfaces of the modified fibers were characterized using techniques like solvatochromism, zeta potential measurements, X-ray Photo electron spectroscopy (XPS), and Scanning Electron Microscopy (SEM). The effect of fiber surface modification on the mechanical as well as electrical properties of the composites was evaluated. Fiber surface modification was found to influence both mechanical as well as electrical properties of the composite. The mechanical properties were found to be improved based on the improved interaction between the fiber and the matrix which in turn was found to be dependent on the surface polarity of the chemically modified fibers. The value of the dielectric constant was found to be influenced when the fiber loading reaches an optimum value. The dielectric constant values of the treated fiber composites were found to be lower than the untreated composites. The electrical conductivity of the composites was found to be dependent on the chemical modification as well as the fiber loading employed. Maximum conductivity was observed for composites with an optimum fiber loading of 40% as well as for those treated with methacryloxy silane. In addition to the other techniques, conductivity measurements can be used as an effective tool to evaluate interfacial adhesion in composites.

Effect of alkali treatment on properties of unidirectional isora fibre reinforced epoxy composites

Unidirectional isora fibre reinforced epoxy composites were prepared by compression moulding. Isora is a natural bast fibre separated from Helicteres isora plant by retting process. The effect of alkali treatment on the properties of the fibre was studied by scanning electron microscopy (SEM), IR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Mechanical properties such as tensile strength, Young's modulus, flexural strength, flexural modulus and impact strength of the composites containing untreated and alkali treated fibres have been studied as a function of fibre loading. The optimum fibre loading for tensile properties of the untreated fibre composite was found to be 49% by volume and for flexural properties the loading was optimised at ∼45%. Impact strength of the composite increased with increase in fibre loading and remained constant at a fibre loading of 54·5%. Alkali treated fibre composite showed improved thermal and mechanical properties compared to untreated fibre composite. From dynamic mechanical analysis (DMA) studies it was observed that the alkali treated fibre composites have higher E' and low tan δ maximum values compared to untreated fibre composites. From swelling studies in methyl ethyl ketone it was observed that the mole percentage of uptake of the solvent by the treated fibre composites is less than that by the untreated fibre composites. From these results it can be concluded that in composites containing alkalised fibres there is enhanced interfacial adhesion between the fibre and the matrix leading to better properties, compared to untreated fibre composites.

Characterization of the barrier properties of composites of HDPE and purified cellulose fibers

The present work presents and discusses the interrelation between composition, morphology, thermal history, mechanical and barrier properties to oxygen and limonene of composites of HDPE/MA-PE/cellulose fibers of significant interest in, among others, food packaging applications. From the overall results, it was observed that increasing the loading of purified alpha-cellulose fibers in the polyethylene matrix beyond 10 wt.% led to a decrease in the permeability coefficient of d-limonene, effect which was found to be primarily related to a decrease in the overall solubility of this strongly plasticizing aroma component. On the other hand, the oxygen permeability was found to decrease to a significant extend with increasing fiber content beyond 5 wt.%, but this effect was more strongly ascribed to a significant decrease in the diffusion coefficient. Therefore, the fibers are thought to generate a more tortuous path for the non-interacting gas molecules to travel across the composites thickness, even when tested at high relative humidity conditions. Optimum fiber loading levels in terms of overall property balance were found to be around 20 wt.%.

Effect of Extrusion Rate and Fiber Loading on Mechanical Properties of Twaron Fiber-thermoplastic Natural Rubber (TPNR) Composites

Mechanical behavior of short Twaron fiber thermoplastic natural rubber (TPNR) has been studied with respect to fiber loading and extrusion rates. The composites are prepared at two different compositions of NR/LLDPE matrixes i.e., 60/40 and 40/60. Twaron fibers are varied from 0 to 25% in the composites. The temperature profile for extrusion is 140, 145, 150, and 155°C for feeding zone, melting zone, mixing zone, and die respectively with the extrusion rate of 30, 50, 80, and 100 rpm. It has been found that the tensile strength, Young’s modulus, and impact strength increases with fiber loading, but the strain at break decreases. The optimum fiber loading in the system is found to be 20% in both blends. However, there is no effect of extrusion rate on the strength of composite observed.

Characterization of Short Nylon-6 Fiber/Acrylonitrile Butadiene Rubber Composite by Thermogravimetry

The thermal degradation of short nylon-6 fiber reinforced acrylonitrile butadiene rubber (NBR) composites with and without epoxy-based bonding agent has been studied by thermogravimetric analysis (TGA). It was found that the onset of degradation shifted from 330.5 to 336.1°C in the presence of short nylon fiber, the optimum fiber loading being 20 phr. The maximum rate of degradation of the composites was lower than that of the unfilled rubber compound, and it decreased with increase in fiber concentration. The presence of epoxy resin-based bonding agent in the virgin elastomer and the composites improved the thermal stability. Results of kinetic studies showed that the degradation of NBR and the short nylon fiber reinforced composites followed first-order kinetics.