scholarly journals Komposit Epoksi Diperkuat Serat Corypha Utan: Karakterisasi Morpologi, Kekuatan Tarik Dan kekuatan Lentur

2019 ◽  
Vol 12 (1) ◽  
pp. 27
Author(s):  
Nasmi Herlina Sari ◽  
Agus Dwi Catur ◽  
Ahmad Safii
Keyword(s):  
Flexural Strength ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Good Alternative ◽  
Epoxy Composites ◽  
Fiber Breakage ◽  
Sem Images ◽  
Thermoset Composites ◽  
Interface Bond

Serat Corypha utan lamarck, yang kaya selulosa, murah, berlimpah memiliki potensi untuk penguatan pada komposit termoset. Penelitian ini bertujuan untuk menyelidiki sifat-sifat dari komposit epoksi berpenguatan serat Corypha utan lamarck. Pembuatan komposit telah dilakukan dengan menggunakan teknik vacuum bagging. Efek penambahan fraksi volume serat Corypha Utan (CU) dengan variasi 20, 25 dan 30 % (fraksi volume) terhadap morpologi, sifat kekuatan tarik dan lentur dari komposit telah diselidiki dan dianalisa. Hasil studi menunjukkan bahwa penambahan fraksi volume serat Corypha Utan secara siknifikan meningkatkan kekuatan tarik dan lentur dari komposit; dikarenakan penyebaran serat merata dalam resin, dan interface yang cukup kuat terbentuk antara serat dan epoksi. Komposit CU/epoksi dengan variasi fraksi volume serat 30% (spesimen  komposit CUh) memiliki nilai kekuatan dan modulus tarik sebesar tur paling tinggi sebesar 28.13 MPa dan 39.40 MPa, berturut-turut. Modulus lentur paling tinggi dimiliki oleh komposit dengan fraksi volume serat CU sebesar 30%. Analisa foto SEM memperlihatkan ikatan interface antara serat-epoksi dan fiber breakage. Hasil ini menunjukkkan bahwa komposit Cu/epoksi dapat menjadi alternatif  sebagai papan komposit komersil.  Corypha Utan fiber, which is rich cellulose, cheap and abundant has the potential for reinforcement in thermoset composites. This study aim is to investigate the properties of epoxy composites reinforced Corypha Utan fibers. The manufacture of composite has been done using vacuum bagging technique. The effect of increasing of the volume fraction of the Corypha utan fibers with variations of 20, 25 dan 30 % (volume fraction) on morphology, the tensile and flexural strength of composites have been investigated and analyzed. The results show that the increase of the volume fraction of Corypha utan fibers significantly increased tensile and flexural of composites; it is due to the dispersion of the fibers in epoxy, and interface bond between fiber and epoxy formed strong enough. The CU/epoxy composite with the volume fraction of the fiber of 30% (Composite CUh specimens) has the highest tensile and flexural strength value of 28,13 MPa and 39,400 MPa, respectively. The moduli’s flexural gives higher value at 30% volume fraction. SEM images demonstrate that interfacial adhesions between fiber-epoxy, and fiber breakage. The result suggests that Corypha utan fibers/epoxy composites can be a good alternative as commercial composites boards, especially for interior applications.

Monitoring of mechanical properties of prestressed glass fiber epoxy composites over 12 months after fabrication

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Flexural Strength ◽  
Compressive Residual Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Initial Increase ◽  
Fiber Volume

Fiber prestressing during matrix curing can significantly improve the mechanical properties of fiber-reinforced polymer composites. One primary reason behind this improvement is the generated compressive residual stress within the cured matrix, which impedes cracks initiation and propagation. However, the prestressing force might diminish progressively with time due to the creep of the compressed matrix and the relaxation of the tensioned fiber. As a result, the initial compressive residual stress and the acquired improvement in mechanical properties are prone to decline over time. Therefore, it is necessary to evaluate the mechanical properties of the prestressed composites as time proceeds. This study monitors the change in the tensile and flexural properties of unidirectional prestressed glass fiber reinforced epoxy composites over a period of 12 months after manufacturing. The composites were prepared using three different fiber volume fractions 25%, 30%, and 40%. The results of mechanical testing showed that the prestressed composites acquired an initial increase up to 29% in the tensile properties and up to 32% in the flexural properties compared to the non-prestressed counterparts. Throughout the 12 months of study, the initial increase in both tensile and flexural strength showed a progressive reduction. The loss ratio of the initial increase was observed to be inversely proportional to the fiber volume fraction. For the prestressed composites fabricated with 25%, 30%, and 40% fiber volume fraction, the initial increase in tensile and flexural strength dropped by 29%, 25%, and 17%, respectively and by 34%, 26%, and 21%, respectively at the end of the study. Approximately 50% of the total loss took place over the first month after the manufacture, while after the sixth month, the reduction in mechanical properties became insignificant. Tensile modulus started to show a very slight reduction after the fourth/sixth month, while the flexural modulus reduction was observed from the beginning. Although the prestressed composites displayed time-dependent losses, their long-term mechanical properties still outperformed the non-prestressed counterparts.

Thermal, Electrical and Physical Properties of Recycled Copper Filled Epoxy Composites

2012 ◽  
Vol 620 ◽  
pp. 208-212
Author(s):  
Mohamd Nur Fuadi Pargi ◽  
Pei Leng Teh ◽  
Salmah Husseinsyah ◽  
Cheow Keat Yeoh
Keyword(s):  
Electrical Conductivity ◽  
Thermal Expansion ◽  
Physical Properties ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Coefficient Of Thermal Expansion ◽  
Filler Loading ◽  
Epoxy Composites ◽  
Milling Machine

The effect of recycled copper filled epoxy composites on thermal, electrical and physical properties were investigated. The recycled copper was collected as a waste from the milling machine. The recycled copper filled epoxy composite was mixed using mechanical stirrer. The effect of volume fraction of recycled copper of the epoxy composites were studied based on the coefficient of thermal expansion (CTE), electrical conductivity hardness and density. Incorporation of recycled copper has decreased the CTE of the composites. The electrical conductivity, hardness and density of the composites increased with increasing of volume fraction and filler loading.

scholarly journals PEMANFAATAN SERBUK TEMPURUNG KELAPA PADA KOMPOSIT Al2O3-EPOXY

2013 ◽  
Vol 3 (2) ◽  
Author(s):  
Ahmad Syafruddin Zohri ◽  
Nasmi Herlina Sari ◽  
S. Sujita
Keyword(s):  
Epoxy Resin ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Method Comparison ◽  
Wear Test ◽  
Epoxy Composites ◽  
Coconut Shell ◽  
Alternative Material ◽  
Coconut Shell Powder ◽  
Shell Powder

The purpose of this research is utilization of coconut shell powder on Al2O3-Epoxy composite so it can be used as an alternative material of brake linings that are enviromentlly friendly. In this research, coconut shell powder is used as a filler on Al2O3-Epoxy composites that are made using hand lay up method. Comparison volume fraction of coconut shell powder and Al2O3 was varied amount 0:40, 10:30, 20:20, 30:10 and 40:0 (%). Adhesive was used is epoxy resin namely amount 60%. Test conducted is wear test. The results showed that utilization of coconut shell powder on Al2O3-Epoxy can be decrease the wear so it can be used as an alternative material of brake linings that are environmentally friendly

scholarly journals A Smart Epoxy Composite Based on Phase Change Microcapsules: Preparation, Microstructure, Thermal and Dynamic Mechanical Performances

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 916 ◽  
Author(s):  
Qinghong Hu ◽  
Yan Chen ◽  
Jiaoling Hong ◽  
Shan Jin ◽  
Guangjin Zou ◽  
...  
Keyword(s):  
Phase Change ◽  
Infrared Thermography ◽  
Temperature Regulation ◽  
Epoxy Composite ◽  
Epoxy Composites ◽  
Thermal Constant ◽  
Good Prospect ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Dynamic Mechanical

Microencapsulated phase change materials (MicroPCMs)-incorporated in epoxy composites have drawn increasing interest due to their promising application potential in the fields of thermal energy storage and temperature regulation. However, the study on the effect of MicroPCMs on their microstructure, thermal and viscoelastic properties is quite limited. Herein, a new type of smart epoxy composite incorporated with polyurea (PU)-shelled MicroPCMs was fabricated via solution casting method. Field emission-scanning electron microscope (FE-SEM) images revealed that the MicroPCMs were uniformly distributed in the epoxy matrix. The thermal stabilities, conductivities, phase change properties, and dynamic mechanical behaviors of the composite were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), thermal constant analyzer and infrared thermography. The results suggested that the heat storage ability of the composites was improved by increasing the MicroPCMs content. The thermal stability of MicroPCMs was found to be enhanced after incorporation into the matrix, and the MicroPCMs-incorporated epoxy composites showed a good thermal cycling reliability. Moreover, the incorporation of MicroPCMs reduced the composites’ storage modulus but increased the glass transition temperature (Tg) as a result of their restriction to the chain motion of epoxy resin. Besides, a less marked heating effect for the composite was explored through infrared thermography analysis, demonstrating the good prospect for temperature regulation application.

scholarly journals Effects of Different Relative Humidities on Flax Fibers prior to Manufacturing Their Composites Based on the Shear Response

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Abdul Moudood ◽  
Anisur Rahman ◽  
Andreas Öchsner ◽  
Md Mainul Islam ◽  
Mohammad Yeakub Ali ◽  
...  
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Absorption Rate ◽  
Moisture Absorption ◽  
Epoxy Composite ◽  
Epoxy Composites ◽  
Engineering Structures ◽  
Sem Images ◽  
Flax Fibers ◽  
Composite Samples

The moisture absorption behavior of flax fiber-reinforced epoxy composites is deliberated to be a serious issue. This property restricts their usage as outdoor engineering structures. Therefore, this study provides an investigation of moisture in flax fibers on the performance of the flax/epoxy composite materials based on their shear responses. The ±45° aligned flax fibers exposed to different relative humidities (RH) and the vacuum infusion process was used to manufacture the composite specimens. The optimum shear strength (40.25 ± 0.75 MPa) was found for the composites manufactured with 35% RH-conditioned flax fibers, but the shear modulus was reduced consistently with increasing RH values. Although shear strength was increased because of fiber swelling with increased moisture absorption rate until 35% RH environments with good microstructures, nonetheless, strength and modulus both started to decrease after this range. A very poor microstructure has been affirmed by the SEM images of the composite samples conditioned at 90% RH environments.

Effect of nano-particles on the tensile, flexural and perforation properties of the glass/epoxy composites

2017 ◽  
Vol 36 (12) ◽  
pp. 900-916 ◽  
Author(s):  
Ali Afrouzian ◽  
Hossein Movahhedi Aleni ◽  
GholamHossein Liaghat ◽  
Hamed Ahmadi
Keyword(s):  
Flexural Strength ◽  
Energy Absorption ◽  
Volume Fraction ◽  
Glass Fibers ◽  
Indentation Test ◽  
Nano Particles ◽  
Fiber Volume ◽  
Sem Images ◽  
Static Indentation ◽  
Strength And Stiffness

The objective of this study is to characterize the damage in glass fiber reinforced composite laminated reinforced with nanosilica particles subjected to tensile, flexural, and transverse loadings. Tensile, three-point bending, quasi-static indentation test, and ballistic impact tests were used in order to obtain the perforation response, flexural and tensile behavior of the composites and nanocomposites. Experimental test series was carried out to determine the tensile and flexural strength and stiffness, impact energy absorption, and failure mechanisms of composites in the presence of nanoparticle. Hand lay-up method has been used to manufacture nanocomposites constituted of 12 layers of 2D woven glass fibers with 40% fiber volume fraction. The composites were reinforced by adding organically modified nano-silica in a 0%, 0.5%, 1%, and 3% ratio in weight with respect to the matrix. Results revealed that in 0.5 wt.% nanoparticles, energy absorption and tensile strength are maximum, but flexural strength has the highest value in 3 wt.%. Furthermore, the highest energy absorption, elastic energy, and energy absorption at maximum force in quasi-static penetration occur in 0.5% nanosilica content. In the case of ballistic tests, effect of nanosilica is more tangible than in quasi-static indentation. Nanocomposite at 0.5% nanosilica recorded higher ballistic limit and energy absorption in comparison with other composites and nanocomposites. SEM images showed that fracture surfaces in 0.5 wt.% nanocomposites are rough and engender more crack tips in comparison with other specimens, which contributes to higher energy absorption in static and dynamic tests.

Influence of Multiwall Carbon Nanotube on mechanical and wear properties of Copper – Iron composite

2020 ◽  
Vol 17 (1) ◽  
pp. 7570-7576 ◽  
Author(s):  
H. Sh. Hammood ◽  
S. S. Irhayyim ◽  
A. Y. Awad ◽  
H. A. Abdulhadi
Keyword(s):  
Carbon Nanotubes ◽  
Volume Fraction ◽  
Hybrid Composites ◽  
Hydraulic Press ◽  
Dry Sliding Wear ◽  
Multiwall Carbon Nanotube ◽  
Wear Properties ◽  
Sem Images ◽  
Wear Rates ◽  
Multiwall Carbon

Multiwall Carbon nanotubes (MWCNTs) are frequently attractive due to their novel physical and chemical characteristics, as well as their larger aspect ratio and higher conductivity. Therefore, MWCNTs can allow tremendous possibilities for the improvement of the necessarily unique composite materials system. The present work deals with the fabrication of Cu-Fe/CNTs hybrid composites manufactured by powder metallurgy techniques. Copper powder with 10 vol. % of iron powder and different volume fractions of Multi-Wall Carbon Nanotubes (MWCNTs) were mixed to get hybrid composites. The hybrid composites were fabricated by adding 0.3, 0.6, 0.9, and 1.2 vol.% of MWCNTs to Cu- 10% Fe mixture using a mechanical mixer. The samples were compressed under a load of 700 MPa using a hydraulic press to compact the samples. Sintering was done at 900°C for 2 h at 5ºC/min heating rate. The microscopic structure was studied using a Scanning Electron Microscope (SEM). The effect of CNTs on the mechanical and wear properties, such as micro-hardness, dry sliding wear, density, and porosity were studied in detail. The wear tests were carried out at a fixed time of 20 minutes while the applied loads were varied (5, 10, 15, and 20 N). SEM images revealed that CNTs were uniformly distributed with relative agglomeration within the Cu/Fe matrix. The results showed that the hardness, density, and wear rates decreased while the percentage of porosity increased with increasing the CNT volume fraction. Furthermore, the wear rate for all the CNTs contents increased with the applied load.

scholarly journals Enhanced flexural properties of aramid fiber/epoxy composites by graphene oxide

2019 ◽  
Vol 8 (1) ◽  
pp. 484-492 ◽  
Author(s):  
Yinqiu Wu ◽  
Bolin Tang ◽  
Kun Liu ◽  
Xiaoling Zeng ◽  
Jingjing Lu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Flexural Strength ◽  
Interfacial Shear Strength ◽  
Flexural Modulus ◽  
Weight Fraction ◽  
Interfacial Shear ◽  
Aramid Fiber ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Pure Epoxy

Abstract The reinforcing effect of graphene oxide (GO) in enhancing the flexural strength and flexural modulus of aramid fiber (AF)/epoxy composites were investigated with GO-AFs at a weight fraction of 0.1-0.7%. The flexural strength and flexural modulus of the composite reached 87.16 MPa and 1054.7 MPa, respectively, which were about 21.19% and 40.86% higher than those of the pure epoxy resin, respectively. In addition, the flexural properties and interfacial shear strength (IFSS) of composite reinforced by GO-AFs were much higher than the composites reinforced by AFs due to GO improved the interfacial bonding between the reinforcement material and matrix.

Flexural behavior of functionally graded polymeric composite beams

2021 ◽  
pp. 152808372110003
Author(s):  
M Atta ◽  
A Abu-Sinna ◽  
S Mousa ◽  
HEM Sallam ◽  
AA Abd-Elhady
Keyword(s):  
Flexural Strength ◽  
Volume Fraction ◽  
Stress Gradient ◽  
Polymeric Composite ◽  
Composite Beams ◽  
Functionally Graded ◽  
Flexural Behavior ◽  
Bending Test ◽  
Polymeric Composite Material ◽  
Fiber Volume

The bending test is one of the most important tests that demonstrates the advantages of functional gradient (FGM) materials, thanks to the stress gradient across the specimen depth. In this research, the flexural response of functionally graded polymeric composite material (FGM) is investigated both experimentally and numerically. Fabricated by a hand lay-up manufacturing technique, the unidirectional glass fiber reinforced epoxy composite composed of ten layers is used in the present investigation. A 3-D finite element simulation is used to predict the flexural strength based on Hashin’s failure criterion. To produce ten layers of FGM beams with different patterns, the fiber volume fraction ( Vf%) ranges from 10% to 50%. A comparison between FGM beams and conventional composite beams having the same average Vf% is made. The experimental results show that the failure of the FGM beams under three points bending loading (3PB) test is initiated from the tensioned layers, and spread to the upper layer. The spreading is followed by delamination accompanied by shear failures. Finally, the FGM beams fail due to crushing in the compression zone. Furthermore, the delamination failure between the layers has a major effect on the rapidity of the final failure of the FGM beams. The present numerical results show that the gradient pattern of FGM beams is a critical parameter for improving their flexural behavior. Otherwise, Vf% of the outer layers of the FGM beams, i.e. Vf% = 30, 40, or 50%, is responsible for improving their flexural strength.

scholarly journals Effect of Terminal Groups on Thermomechanical and Dielectric Properties of Silica–Epoxy Composite Modified by Hyperbranched Polyester

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2451
Author(s):  
Jianwen Zhang ◽  
Dongwei Wang ◽  
Lujia Wang ◽  
Wanwan Zuo ◽  
Lijun Zhou ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Binding Energy ◽  
Epoxy Resin ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Mean Square Displacement ◽  
Mean Square ◽  
Hyperbranched Polyester ◽  
Free Volume Fraction

To study the effect of hyperbranched polyester with different kinds of terminal groups on the thermomechanical and dielectric properties of silica–epoxy resin composite, a molecular dynamics simulation method was utilized. Pure epoxy resin and four groups of silica–epoxy resin composites were established, where the silica surface was hydrogenated, grafted with silane coupling agents, and grafted with hyperbranched polyester with terminal carboxyl and terminal hydroxyl, respectively. Then the thermal conductivity, glass transition temperature, elastic modulus, dielectric constant, free volume fraction, mean square displacement, hydrogen bonds, and binding energy of the five models were calculated. The results showed that the hyperbranched polyester significantly improved the thermomechanical and dielectric properties of the silica–epoxy composites compared with other surface treatments, and the terminal groups had an obvious effect on the enhancement effect. Among them, epoxy composite modified by the hyperbranched polyester with terminal carboxy exhibited the best thermomechanical properties and lowest dielectric constant. Our analysis of the microstructure found that the two systems grafted with hyperbranched polyester had a smaller free volume fraction (FFV) and mean square displacement (MSD), and the larger number of hydrogen bonds and greater binding energy, indicating that weaker strength of molecular segments motion and stronger interfacial bonding between silica and epoxy resin matrix were the reasons for the enhancement of the thermomechanical and dielectric properties.

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