Fracture Toughness of Random Short Natural Fibers Polyester Composites

2018 ◽  
Vol 18 ◽  
pp. 94-105 ◽  
Author(s):  
Mansour Rokbi ◽  
Abdellatif Imad ◽  
Christophe Herbelot ◽  
Zouhyer Belouadah
Keyword(s):  
Mechanical Properties ◽  
Strain Energy ◽  
Structural Changes ◽  
Natural Fibers ◽  
Strain Energy Release ◽  
Alkaline Treatment ◽  
Alfa Fibers ◽  
Naoh Solution ◽  
Factor Evaluation ◽  
Properties Of Composites

The aim of this paper is to describe the fracture behavior of composites reinforced with two layers of Alfa random. An alkaline treatment at 1, 5 and 10% for a period of 24 hours with NaOH solution was performed to improve the mechanical properties of Alfa fibers. The morphological and structural changes that occurred in fiber after treatment; and the effects of this treatment on the mechanical properties of composites were discussed and were supported by Scanning Electron Microscopy. Many aspects of studies reported in this paper are original, such as the strain energy release rate and intensity factor evaluation of Alfa composites.

scholarly journals The Influence of Alkaline Treatment of Recycled Natural Materials on the Properties of Epoxy Resin Composites

2018 ◽  
Vol 14 (4) ◽  
pp. 45-53
Author(s):  
Hamza M. Kamal ◽  
Mohammed J. Kadhim ◽  
Raeid K. Mohammed
Keyword(s):  
Epoxy Resin ◽  
Low Cost ◽  
Natural Fibers ◽  
Alkaline Treatment ◽  
Walnut Shell ◽  
Reinforced Composites ◽  
Jute Fibers ◽  
Naoh Solution ◽  
Shell Powder ◽  
Properties Of Composites

Natural fibers and particles reinforced composites are being broadly used due to their bio and specific properties such as low density and easy to machine and production with low cost. In this work, water absorption and mechanical properties such as tensile strength, flexural strength and impact strength of recycled jute fibers reinforced epoxy resin were enhanced by treating these fibers with alkaline solution. The recycled jute fibers were treated with different concentration of (NaOH) solution at (25 0C) for a period of (24) hours. From the obtained results, it was found that all these properties are improved when fibers treated with (7.5wt% NaOH) related to untreated fibers. Conversely, the mentioned properties of composites decreased after fibers treated with (10wt% NaOH). In addition, the hybrid composite with recycled jute fibers and recycled walnut shell powder showed obvious enhancement in the above-mentioned properties.

scholarly journals Mechanical Properties of Mortars Reinforced with Amazon Rainforest Natural Fibers

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 155
Author(s):  
Régis Pamponet da Fonseca ◽  
Janaíde Cavalcante Rocha ◽  
Malik Cheriaf
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Natural Fibers ◽  
Construction Materials ◽  
Hot Water ◽  
Amazon Rainforest ◽  
Hot Water Treatment ◽  
Composite Binder ◽  
Naoh Solution ◽  
Reference Samples

The addition of natural fibers used as reinforcement has great appeal in the construction materials industry since natural fibers are cheaper, biodegradable, and easily available. In this work, we analyzed the feasibility of using the fibers of piassava, tucum palm, razor grass, and jute from the Amazon rainforest as reinforcement in mortars, exploiting the mechanical properties of compressive and flexural strength of samples with 1.5%, 3.0%, and 4.5% mass addition of the composite binder (50% Portland cement + 40% metakaolin + 10% fly ash). The mortars were reinforced with untreated (natural) and treated (hot water treatment, hornification, 8% NaOH solution, and hybridization) fibers, submitted to two types of curing (submerged in water, and inflated with CO2 in a pressurized autoclave) for 28 days. Mortars without fibers were used as a reference. For the durability study, the samples were submitted to 20 drying/wetting cycles. The fibers improved the flexural strength of the mortars and prevented the abrupt rupture of the samples, in contrast to the fragile behavior of the reference samples. The autoclave cure increased the compressive strength of the piassava and tucum palm samples with 4.5% of fibers.

Development of breathable Janus superhydrophobic polyester fabrics using alkaline hydrolysis and blade coating

2018 ◽  
Vol 89 (6) ◽  
pp. 959-974 ◽  
Author(s):  
Seonyoung Youn ◽  
Chung Hee Park
Keyword(s):  
Mechanical Properties ◽  
Alkaline Hydrolysis ◽  
Structural Changes ◽  
Treatment Time ◽  
Volume Ratio ◽  
Alkaline Treatment ◽  
The Other ◽  
Solution Temperature ◽  
Optimal Conditions ◽  
Wetting Properties

Alkaline hydrolysis is a common finishing method that is used to give polyester (polyethylene terephthalate, PET) a more natural touch and improved luster via chemical or physical changes in the fibers. However, its potential as a tool for surface modification in the development of single-sided superhydrophobic materials has not been studied yet. In this research, Janus superhydrophobic PET fabrics with asymmetric wetting properties (one side of the PET surface was rendered superhydrophobic while the other side was simply hydrophobic) were fabricated in two steps. Fine roughness was first achieved on the surface of PET fabrics by alkaline hydrolysis. Subsequently, optimized foam-coating emulsions were applied on only one surface of the alkaline-hydrolyzed PET. Alkaline treatment time, solution temperature, and viscosity of the foam-coating emulsions were varied to find optimal conditions in terms of structural changes, mechanical properties, superhydrophobicity, and absorption ability. The specimen treated with an aqueous solution of 8% sodium hydroxide at 70℃ for 60 min and coated with the mixture of the fluoro-emulsion and thickener in the volume ratio of 40:2 was determined to be the optimal conditions for the Janus superhydrophobic property. This sample showed a contact angle of 162.8° and a shedding angle of 5.6° on one side, whereas it completely permitted the percolation of water drops on the other side within 109 s. The mechanical properties of the developed Janus PET under the optimal conditions did not decrease significantly; its weight and tensile strength were found to have decreased by 3.3% and 19.2%, respectively. Furthermore, the single-sided superhydrophobic specimen demonstrated higher moisture transmissibility than the double-sided coated PET under the same alkaline treatment conditions. The method developed herein eliminates the requirement for an additional process to deliver nanoscale surface roughness and has the potential to produce waterproof–breathable PET fabrics for outdoor clothing.

The mechanical, thermal and sound absorption properties of flexible polyurethane foam composites reinforced with artichoke stem waste fibers

2020 ◽  
pp. 152808372093419 ◽  
Author(s):  
Hilal Olcay ◽  
Emine Dilara Kocak
Keyword(s):  
Mechanical Properties ◽  
Polyurethane Foam ◽  
Renewable Resources ◽  
Alkali Treatment ◽  
Natural Fibers ◽  
Morphological Properties ◽  
Sound Insulation ◽  
Synthetic Fibers ◽  
Flexible Polyurethane ◽  
Properties Of Composites

Recently, due to environmental concerns and dependence on depleted resources, the use of renewable resources has become important in the preparation of various industrial materials. The use of natural fibers instead of petroleum-based synthetic fibers traditionally used in the production of composite materials provides many advantages in terms of both environmental and cost. The utilization of agricultural wastes as natural fibers also contributes significantly to the reduction and reuse of wastes, which is one of the objectives of sustainable development. In this study, artichoke stem waste fibers reinforced polyurethane foam composites were obtained. The fibers were treated with alkaline surface treatment at different concentrations (5% and 10%) of sodium hydroxide (NaOH) and durations (5, 10 and 15 min). The optimal alkali method was determined and applied to the fibers and its effect on composites was also investigated. Treated and untreated fibers were combined with polyurethane (PU) matrix at different reinforcement ratios (5, 10, 15 and 20%) to produce bio-fiber based composites. Depending on these reinforcement rates and alkali treatment, the mechanical properties of composites such as strength, elongation and modulus were investigated. The composites, which have the best mechanical properties, were selected and these composites were evaluated in terms of thermal and sound insulation with considering their morphological properties. It has been determined that artichoke stem waste fibers can provide good mechanical, thermal and sound insulation properties in the composites, and thus it has been found that great advantages can be achieved in terms of cost and ecology.

Thermal, morphological and mechanical properties of composites based on polyamide 6 with cellulose, silica and their hybrids from rice husk

2020 ◽  
pp. 002199832097829
Author(s):  
Renato P Melo ◽  
Marcelo P da Rosa ◽  
Paulo H Beck ◽  
Lucas GP Tienne ◽  
Maria de Fátima V Marques
Keyword(s):  
Mechanical Properties ◽  
Rice Husk ◽  
Natural Fibers ◽  
Polyamide 6 ◽  
Mechanical Analysis ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Cellulosic Fibers ◽  
The One ◽  
Properties Of Composites

The use of cellulosic fibers from different natural sources as fillers in polymer matrices to improve their properties has been extensively studied in the last years. It is mainly due to the vast availability of natural fibers as well as their biodegradability. The purpose of this present work was to extract cellulose, silica, and cellulose-silica fillers – these last called “hybrids” – from rice husk through delignification and subsequent oxidation and, then, prepare composites with polyamide 6 and improve mainly its thermal-mechanical properties. The content of 10 wt.% of fillers was inserted in PA 6 matrix. Infrared spectroscopy pointed the main characteristic peaks of cellulose and silica of hybrids, as thermogravimetric analysis showed high thermal stability of fillers, allowing their incorporation in PA-6 matrix by extrusion method. Thermo dynamic-mechanical analysis showed, in a general overview, a significant improvement of mechanical properties of composites, as elastic modulus, compared with neat polyamide-6, mainly the one with 2.5 wt% of silica and 7.5% of cellulose. This last also showed increasing of degree of crystallinity, measured by differential scanning calorimetry, showing the extraction efficiency of fillers from rice husk as well as the potential application of composites as structural components in automotive parts.

Mechanical properties of composites made of hybrid fabric impregnated with silica nanoparticles and epoxy resin

2017 ◽  
Vol 31 (26) ◽  
pp. 1750235
Author(s):  
N. Kordani ◽  
M. Alizadeh ◽  
F. Lohrasby ◽  
R. Khajavi ◽  
H. R. Baharvandi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Natural Fibers ◽  
Shear Thickening ◽  
Silica Particles ◽  
Nano Silica ◽  
Shear Thickening Fluid ◽  
Synthetic Fibers ◽  
Hybrid Fabric ◽  
Properties Of Composites

In this study, the mechanical properties of composites will be examined which were made from Kenaf and hybrid fabric with a simple structure that was coated with epoxy resin and nano silica particles. This fabric cotton has a different situation in terms of yarn score and the type of fiber that is used in textiles. Nano silica particles of 200 nm, polyethylene glycol with 200 molecular weights and ethanol with mechanical weight molecular with ratio of 6:1 will be mixed. Suspension of 60% was chosen according to the silica particles. The D6264 standard test for concentrated force was carried out through the cone edge to determine the strength of each of the samples. Increasing of resistance against penetration in the Kenaf samples from the raw until impregnated with the shear thickening fluid is less than the hybrid samples. Slippage of the fibers with the change of round edge indenter to cone edge indenter has changed. Penetration by cone edge to the cloth is done with lower force and it shows the effect of slippage of fibers on the resistance of the penetration. Samples impregnated with the shear thickening fluid in comparison with epoxy resin have lower resistance. Slippage of natural fibers in comparison with synthetic fibers is lower and on the other hand the average of friction between fibers in the natural fibers is more than synthetic fibers.

scholarly journals Bioactive coatings for direct skeletal attachment applications for lower limb prostheses

2021 ◽  
Author(s):  
Omar Rodríguez
Keyword(s):  
Mechanical Properties ◽  
Titanium Dioxide ◽  
Mass Loss ◽  
Strain Energy ◽  
Critical Strain ◽  
Strain Energy Release ◽  
Inhibition Zone ◽  
Release Rates ◽  
Energy Release Rates ◽  
Strain Energy Release Rates

To tackle the current drawbacks with metallic implants used in direct skeletal attachment, novel bioactive glasses are considered as implant coatings in order to reduce bacterial infections and promote bone cell growth. Silica-based and borate-based glasses, with increasing amounts of titanium dioxide at the expense of either silica (for the silica-based glasses) or borate (for the borate-based glasses), respectively, were synthesized and characterized to determine the parameters that define a glass capable of inhibiting bacterial growth, stimulating cell proliferation and offering mechanical stability when enameled into a surgical alloy. The effect of substituting the glass backbone with titanium dioxide, in both glass series, is also investigated with respect to its effect on both biocompatibility and mechanical properties of the resultant glass/implant constructs. Borate-based glasses exhibited greater processing windows compared to the silica-based glasses, making them more desirable for coating applications. They also exhibited superior performance in terms of their in vitro bioactivity and biocompatibility, over their silica-based counterparts, due to their higher solubility and greater ability to inhibit S. epidermidis and E. coli bacteria. Specifically, glass BRT0 (control borate-based glass, with no titanium incorporated) exhibited an inhibition zone against S. epidermidis of 17.5 mm and a mass loss of 40% after 30 days, with BRT3 (borate-based glass, with 15 mol% titanium incorporated) exhibiting an inhibition zone against S. epidermidis of 7.6 mm and a mass loss of 34% after 30 days. Furthermore, borate-based glasses with greater titanium dioxide contents exhibited superior mechanical properties (e.g. bulk hardness, and critical strain energy release rates), which could be attributed to their more closely matched coefficients of thermal expansion with the titanium alloy substrate, Ti6Al4V, to which they were adhered. The critical strain energy release rates in mode I for the silica-based coating/substrate system ranged from 6.2 J/m2 (for SRT0, control silica-based glass with no titanium) to 12.08 J/m2 (for SRT3), whereas for the borate-based systems they ranged from 10.86 J/m2 (for BRT0) to 18.5 J/m2 (for BRT3), with the increase for the borate-based glasses being attributed to the presence of compressive residual stresses in the coating after application.

scholarly journals Serat Pelepah Sagu Sebagai Alternatif Pengganti Serat Sintesis Fiberglass

2021 ◽  
Vol 6 (1) ◽  
pp. 14
Author(s):  
Budiawan Sulaeman ◽  
Rakhmawati Natsir
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Composite Material ◽  
Glass Fiber ◽  
Fiber Diameter ◽  
Natural Fibers ◽  
Fiber Volume ◽  
Synthetic Fibers ◽  
Matrix Volume ◽  
Naoh Solution

Tujuan penelitian ini untuk menganalisis pengaruh ukuran besar diameter serat pelepah sagu terhadap sifat mekanik kekuatan tarik, menganalisis sifat mekanik tarik material komposit yang diperkuat serat pelepah sagu.Berdasarkan hasil penelitian; (1). Larutan NAoH berpengaruh terhadap kuat Tarik specimen, hal ini ditunjukkan pada 2,5% (NAoH terhadap H2O). Nilai kekuatan tariknya 49,486 N/mm2. (2). Serat pelepah sagu kuat tariknya jauh dibawah serat gelas. (48,435 N/mm2< 323 N/mm2). Hal ini disebabkan rongga yang terdapat di serat sintesis lebih rapat dibanding serat alami. (3). Berdasarkan variabel yang diteliti, kekuatan tarik (Ftu) dengan nilai tertinggi terjadi pada komposit (volume 85% matriks : 15% serat) yaitu sebesar 3,12 beban 11824 N. (4). Kekuatan tarik mengalami kenaikan terhadap peningkatan komposisi volume serat. (5). Spesimen uji yang mengalami regangan dan patah pada titik load yaitu pada komposisi volume 85% matriks : 15% serat sebesar 3,12 MPa dengan regangan sebesar 8% dan modulus young yang terjadi sebesar 38,615  MPa.The purpose of this study was to analyze the effect of the size of the sago frond fiber diameter on the mechanical properties of the tensile strength, to analyze the tensile mechanical properties of the composite material reinforced by sago frond fibers. Based on research results; (1) NaOH solution affects the tensile strength of the specimen. This is shown at 2.5% (NaOH to H2O), the tensile strength value is 49.486 N/mm2. (2) Sago frond fiber has a tensile strength far below the glass fiber (48,435 N/mm2 <323 N/mm2). This is because the cavities in synthetic fibers are denser than natural fibers. (3) Based on the variables studied, the tensile strength (Ftu) with the highest value occurs in the composite (85% matrix volume: 15% fiber), which is 3.12 load 11824 N. (4) Tensile strength increases with the increase in fiber volume composition. (5) The test specimens that experienced a strain and fracture at the load point, namely the composition of volume 85% matrix: 15% fiber was 3.12 MPa with a strain of 8% and the modulus young that occurred was 38.615 MPa.

scholarly journals Mechanical Behavior of Natural Fiber Composite Material

2021 ◽  
Author(s):  
Vikas Ghanwat ◽  
Jivan Mule ◽  
Saurabh Telore ◽  
Vijay Bhosale ◽  
Sudarshan Patale
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Composite Laminates ◽  
Fiber Length ◽  
Strain Energy ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Natural Fibers ◽  
Industrial Applications ◽  
Coir Fiber

The use of natural fibers as reinforcement in polymeric composites is increasing thanks to the improvements in properties that fibers can provide to the merchandise. Composites materials were prepared by compression molding technique with hand layup process. Treatment of fiber with 2% NaOH was carried out in order to improve the interfacial bonds between fiber and matrix leading to better mechanical properties of the spathe-fiber-reinforced composite laminates. Filler loading as 5% by volume of coir fiber or epoxy resin composites have been formulated. The fiber length was chosen as 5mm, 10mm & 15mm and the ratio of epoxy resin: hardener was maintained as 10:0.8. A total three plates with dimension as 300 mm х 300 mm х 4 mm were produced and specimens as per the varied ASTM standard were tested to determine the ultimate tensile strength, strain energy, flexural strength, strain energy and micro hardness value for different configuration. It was observed that the lastingness of epoxy resin/ coir fiber composites was maximum at 15mm fiber length (16.27 N/mm2). The charpy notch impact strength was also maximum at 15mm fiber length (10.87 kJ/m2). The results show good mechanical properties and hint us as a replacement for conventional materials in industrial applications.

Gamma Radiation Effects on Mechanical Properties of Carbon/Epoxy Composites

2006 ◽  
Vol 518 ◽  
pp. 549-554 ◽  
Author(s):  
D.R. Sekulić ◽  
I.M. Djordjević ◽  
M.V. Gordić ◽  
Zijah Burzić ◽  
M.M. Stevanović
Keyword(s):  
Mechanical Properties ◽  
Strain Energy ◽  
Radiation Effects ◽  
Elevated Temperatures ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Transverse Tensile ◽  
Transverse Tensile Strength ◽  
Gamma Irradiated ◽  
Epoxy Matrices

Unidirectional and angle-ply carbon/epoxy laminates were gamma irradiated up to doses of 12 and 20 MGy. Composites with two different, low and high temperature epoxy matrices have been submitted to irradiation and subsequent mechanical testing. The radiation effects were studied by measuring in-plane, interalminar shear and transverse tensile strength, as well as interlaminar strain energy release rate of tested composites. The immersion of composite plate in water at 80 oC and mechanical measurements at elevated temperatures emphasized irradiation effects on mechanical properties.

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