Epoxy-matrix nanocomposites reinforced by electrospun polymeric nanofibrous layers: PAN, PA-6,6, and hybrid PAN/PA-6,6

2021 ◽  
pp. 095440622110426
Author(s):  
Farzin Asghari Arpatappeh ◽  
Ali Akbar Gharehaghaji ◽  
Hooshang Nosraty
Keyword(s):  
Epoxy Matrix ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Electrospun Nanofiber ◽  
The Matrix ◽  
Low Volume ◽  
Enhanced Properties ◽  
The Impact ◽  
Matrix Nanocomposites ◽  
Advanced Applications

Composite materials with nanofibrous reinforcements are capable of high mechanical performance and enhanced properties despite their low volume fraction of reinforcement. In this study, tensile properties of epoxy-matrix nanocomposites were investigated after reinforcing by hand layup method implementation of randomly oriented electrospun nanofiber layers. The reinforcements were produced from polyacrylonitrile (PAN), Polyamide-6,6 (PA-6,6), and their 50/50 hybrid. The results indicated that PAN enhanced the tensile toughness of the matrix by almost 4 times, increasing both the ductility (an expected 23% due to fiber being more elastic than the matrix) and the ultimate tensile strength (a surprising 35% even though the fibers were less stiff than the matrix). These results indicate significant improvements in the impact properties for advanced applications. The results revealed that PA-6,6 did not show the characteristics of a promising reinforcement whether used solely or added to PAN.

Synthesis of exfoliated graphene–montmorillonite hybrids as the fillers for epoxy composites

2018 ◽  
Vol 53 (3) ◽  
pp. 315-326 ◽  
Author(s):  
Shengjuan Li ◽  
Zhihong Yang ◽  
Jianmei Xu ◽  
Jing Xie ◽  
Jian Sun
Keyword(s):  
Epoxy Matrix ◽  
Volume Fraction ◽  
Layer Structure ◽  
Epoxy Composites ◽  
Matrix Composites ◽  
Organic Montmorillonite ◽  
Exfoliated Graphene ◽  
Graphene Flakes ◽  
Low Volume ◽  
The Impact

Graphene was prepared by microwave reduction of graphite oxide and organic montmorillonite was obtained by the intercalation modification of montmorillonite. The hybrids with various mass ratios of organic montmorillonite/graphene (mOMMT:mGNS = 1:1, 5:1, 10:1, 20:1 and 30:1) were primarily prepared, following which the epoxy matrix composites incorporated with organic montmorillonite–graphene hybrids were synthesized. The results indicate that graphene sheets are further exfoliated to fewer-layer structure and organic montmorillonite interlayer has been intercalated by graphene flakes after the combination of graphene and organic montmorillonite, suggesting the synergistic dispersion of these two components. Organic montmorillonite shows completely exfoliated structure at low ratios (1:1 and 5:1) and intercalated structure at high ratios (10:1, 20:1 and 30:1). Among all the hybrids with various organic montmorillonite/graphene ratios, the hybrids at the ratio of 5:1 present better dispersion and are more beneficial to enhancing the mechanical properties of the epoxy matrix composites. Moreover, compared with graphene and organic montmorillonite fillers, the introduction of organic montmorillonite–graphene hybrids into epoxy increases the mechanical strength more efficiently, especially increasing the impact strength of epoxy by 140.8%, indicating the synergistic reinforcement of these two components. The composite filled with organic montmorillonite–graphene hybrids exhibits better thermal stability than pure epoxy, but slightly poorer than the composites incorporated with graphene, which may be attributed to the low volume fraction of the hybrids in epoxy composites.

scholarly journals Effect of Submicron Glass Fiber Modification on Mechanical Properties of Short Carbon Fiber Reinforced Polymer Composite with Different Fiber Length

2020 ◽  
Vol 4 (1) ◽  
pp. 5
Author(s):  
Nhan Thi Thanh Nguyen ◽  
Obunai Kiyotaka ◽  
Okubo Kazuya ◽  
Fujii Toru ◽  
Shibata Ou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Glass Fiber ◽  
Fiber Length ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Fiber Concentration ◽  
Static Tests ◽  
The Impact

In this research, three kinds of carbon fiber (CF) with lengths of 1, 3, and 25 mm were prepared for processing composite. The effect of submicron glass fiber addition (sGF) on mechanical properties of composites with different CF lengths was investigated and compared throughout static tests (i.e., bending, tensile, and impact), as well as the tension-tension fatigue test. The strengths of composites increased with the increase of CF length. However, there was a significant improvement when the fiber length changed from 1 to 3 mm. The mechanical performance of 3 and 25 mm was almost the same when having an equal volume fraction, except for the impact resistance. Comparing the static strengths when varying the sGF content, an improvement of bending strength was confirmed when sGF was added into 1 mm composite due to toughened matrix. However, when longer fiber was used and fiber concentration was high, mechanical properties of composite were almost dependent on the CF. Therefore, the modification effect of matrix due to sGF addition disappeared. In contrast to the static strengths, the fatigue durability of composites increased proportionally to the content of glass fiber in the matrix, regardless to CF length.

Fibre-Cement Paste Transition Zone

1994 ◽  
Vol 370 ◽  
Author(s):  
Vahan Agopyan ◽  
Holmer Savastano
Keyword(s):  
Transition Zone ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Polypropylene Fibres ◽  
Impact Performance ◽  
The Matrix ◽  
Vegetable Fibre ◽  
Electron Image ◽  
Backscattered Electron ◽  
The Impact

AbstractThe characteristics of fibres and paste of ordinary Portland cement transition zone are analysed and correlated to the mechanical properties of the produced composites. The water-cement ratio of the matrix varies from 0.30 to 0.46 and the age of the specimens varies from 7 to 180 days. Composites of vegetable fibres (coir, sisal and malva) are compared with those of chrysotile asbestos and polypropylene fibres. The analysis is made by backscattered electron image (BSEI) and energy dispersive spectroscopy (EDS). Mechanical tests evaluate the composite tensile strength and ductility.Mainly for vegetable fibre composites the transition zone is porous, cracked and rich in calcium hydroxide macrocrystals. These results are directly associated with the fibre-matrix bonding and with the composite mechanical performance. Further studies considering the impact performance of the composites compare the porosity of the transition zone with the toughness of the composites.

Investigation of Meniscus Effect on Microbond Test of Typha Fiber/Epoxy Matrix

2020 ◽  
Vol 402 ◽  
pp. 14-19
Author(s):  
Andri Afrizal ◽  
Ikramullah ◽  
Syarizal Fonna ◽  
Syifaul Huzni
Keyword(s):  
Epoxy Matrix ◽  
Maximum Stress ◽  
Interfacial Shear Strength ◽  
Von Mises Stress ◽  
Microbond Test ◽  
The Matrix ◽  
The Difference ◽  
Von Mises ◽  
The Impact ◽  
Fiber Radius

The microbond test was one of the methods to examine the interfacial shear strength (IFSS) value of fiber and polymer matrix. The meniscus angle that formed at both ends of the matrix is difficult to control while manufacturing the specimen for the microbond test. Therefore, the effect of meniscus angle must be evaluated. In this paper, we evaluated the impact of variations of the meniscus angle against the maximum von-mises stress and the IFSS value of the Typha fiber epoxy matrix by finite element method. The geometry of the microbond test specimen was modeled with 0.25 mm fiber radius, 2 mm fiber length, 1.75 mm embedded length of the matrix, and varied the meniscus angles with 22°, 30°, 45°, 60°, 75°, and 90°. The mesh type quad-dominated CAX4R is used on fiber and matrix, while quad COHAX4 is applied to the cohesive element between fiber and matrix. The constantly applied displacement was adjusted to the upper end of the fiber at 0.6 mm. The simulation results showed that the difference in maximum stress obtained in each model. Furthermore, that is not given much difference in IFSS value. It can be concluded that the meniscus angle affects the maximum von-mises stress but not too much-affected IFSS value of the fiber and epoxy matrix.

scholarly journals Rheological and Mechanical Properties of Silica/Nitrile Butadiene Rubber Vulcanizates with Eco-Friendly Ionic Liquid

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2763
Author(s):  
Munir Hussain ◽  
Sohail Yasin ◽  
Hafeezullah Memon ◽  
Zhiyun Li ◽  
Xinpeng Fan ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Volume Fraction ◽  
High Strength ◽  
Crosslinking Density ◽  
Mechanical And Thermal Properties ◽  
Butadiene Rubber ◽  
Transmission Electron ◽  
The Matrix ◽  
Silica Dispersion ◽  
The Impact

In this paper we designed greener rubber nanocomposites exhibiting high crosslinking density, and excellent mechanical and thermal properties, with a potential application in technical fields including high-strength and heat-resistance products. Herein 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) ionic liquid was combined with silane coupling agent to formulate the nanocomposites. The impact of [EMIM]OAc on silica dispersion in a nitrile rubber (NBR) matrix was investigated by a transmission electron microscope and scanning electron microscopy. The combined use of the ionic liquid and silane in an NBR/silica system facilitates the homogeneous dispersion of the silica volume fraction (φ) from 0.041 to 0.177 and enhances crosslinking density of the matrix up to three-fold in comparison with neat NBR, and also it is beneficial for solving the risks of alcohol emission and ignition during the rubber manufacturing. The introduction of ionic liquid greatly improves the mechanical strength (9.7 MPa) with respect to neat NBR vulcanizate, especially at high temperatures e.g., 100 °C. Furthermore, it impacts on rheological behaviors of the nanocomposites and tends to reduce energy dissipation for the vulcanizates under large amplitude dynamic shear deformation.

MICROSTRUCTURE AND RESISTIVITY OF CARBON NANOTUBE AND NANOFIBER/EPOXY MATRIX NANOCOMPOSITE

2002 ◽  
Vol 01 (05n06) ◽  
pp. 719-723 ◽  
Author(s):  
JIN-HONG DU ◽  
ZHE YING ◽  
SHUO BAI ◽  
FENG LI ◽  
CHAO SUN ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Epoxy Matrix ◽  
Single Walled Carbon Nanotubes ◽  
Epoxy Nanocomposites ◽  
Multiwalled Carbon ◽  
Pure Epoxy ◽  
The Matrix ◽  
Walled Carbon Nanotubes ◽  
Matrix Nanocomposites ◽  
Matrix Nanocomposite

Single-walled carbon nanotubes (SWNTs), multiwalled carbon nanotubes (MWNTs) and vapor-grown carbon nanofibers (VGCNFs)/epoxy matrix nanocomposites were prepared, respectively. The microstructure of the nanocomposites was observed by SEM and the resistivities of the nanocomposites with different concentration of CNTs/VGCNFs were measured. Based on the experimental results, the dispersion of SWNTs and MWNTs were relatively poor but that of VGCNFs is uniform within the matrix. The resistivitiy of pure epoxy is about 1010.5Ω · cm and several orders of magnitude higher than those of SWNT, MWNT and VGCNF/epoxy nanocomposites. The resistivities of the nanocomposites drop with the increase of the CNTs/VGCNFs content in the matrix and the resistivity of VGCNFs/epoxy nanocomposites was much lower than that of CNT/epoxy nanocomposites.

The Influence of Ni on the Microstructure of Co-Base ODS Alloys

2012 ◽  
Vol 535-537 ◽  
pp. 1011-1014 ◽  
Author(s):  
Lin Zhang ◽  
Xin Bo He ◽  
Ming Li Qin ◽  
Ye Liu ◽  
Xuan Hui Qu
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Mechanical Alloying ◽  
Cleavage Fracture ◽  
Fracture Strength ◽  
Volume Fraction ◽  
Secondary Phases ◽  
The Matrix ◽  
Ods Alloys ◽  
Low Volume

Co-based ODS alloys strengthened by γ΄ precipitates and nanosized oxides are promising high-temperature structural materials. Single solid solution of Al and W in the matrix can not be achieved after mechanical alloying, resulting in the formation of low volume fraction of γ΄ phase and several kinds of secondary phases. The addition of Ni promotes the precipitation of γ΄ phase and reduces the amount of secondary phases by the enlargement of the solid solution limit of Al and W within the matrix. In comparison with the lower fracture strength and cleavage fracture mode of the alloy without the addition of Ni, Ni-containing Co-base ODS alloys exhibit much higher fracture strength and obvious ductile facture mode.

Determination of the relationship between microstructure and constitutive behaviour of nodular cast iron with a unit cell model

2005 ◽  
Vol 40 (2) ◽  
pp. 107-116 ◽  
Author(s):  
L Collini ◽  
G Nicoletto
Keyword(s):  
Cast Iron ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Cell Model ◽  
Nodular Cast Iron ◽  
Unit Cell ◽  
Constitutive Law ◽  
Cast Irons ◽  
Present Contribution ◽  
The Matrix

Unit cell models have been proposed to predict the constitutive law and failure of ductile materials with complex microstructures, such as ferritic nodular cast iron and particulate metal matrix composites (PMMCs). The present contribution aims to extend this modelling approach to the prediction of the constitutive response of nodular cast iron with a mixed ferritic/pearlitic matrix. The finite element method is used within the framework of continuum mechanics to carry out the calculations. The effect of some microstructural features, such as graphite volume fraction and ferrite-pearlite ratio of the matrix, on the mechanical performance is determined. The computational results are compared to results obtained in a previous experimental activity on nodular cast irons.

Relation between Impact Properties and Interfacial Strength of UHMWPE/VE Composites

2011 ◽  
Vol 284-286 ◽  
pp. 161-164
Author(s):  
Chun Ying Min ◽  
Hao Jie Song ◽  
Peng Han ◽  
Lei Chen ◽  
Liang Sen Liu
Keyword(s):  
Energy Absorption ◽  
Volume Fraction ◽  
Interfacial Strength ◽  
Woven Fabric ◽  
Impact Properties ◽  
Interfacial Bonding Strength ◽  
Polyethylene Fiber ◽  
Matrix Volume ◽  
The Matrix ◽  
The Impact

This study presents impact properties and interfacial strength of Ultra-high molecular weight polyethylene fiber plain woven fabric reinforced vinyl ester composites with different matrix volume fraction. The interfacial strength was found to be decreased by reducing the matrix volume fraction. Stress, strain and energy absorption per thickness in the impact process were evaluated and the relation between these impact parameters and interfacial strength of the laminates were investigated. The maximum stress was decreased and the maximum strain was increased with the drop of interfacial bonding strength. The experiment results also revealed that the sample with a matrix volume fraction 23% showed higher energy absorption than other ones.

scholarly journals Effect of Harsh Environmental Conditions on the Impact Response of Carbon Composites with Filled Matrix by Cork Powder

2021 ◽  
Vol 11 (16) ◽  
pp. 7436
Author(s):  
Marco P. Silva ◽  
Paulo Santos ◽  
João Parente ◽  
Sara Valvez ◽  
Paulo N. B. Reis
Keyword(s):  
Exposure Time ◽  
Epoxy Matrix ◽  
Mechanical Performance ◽  
Maximum Load ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Wide Range ◽  
Hostile Environments ◽  
The Impact

Composites are used in a wide range of engineering applications, as a result, exposure to hostile environments is rather common and its mechanical properties degradation is unavoidable. It is necessary to have a complete understanding of the impact of hostile environments on mechanical performance, namely critical solicitations as low velocity impacts. Therefore, this work intends to analyse the low velocity impact response of a carbon fibre/epoxy composite, and a similar architecture with an epoxy matrix filled with cork, after immersion into different solutions: diesel, H2SO4, HCl, NaOH, distilled water, seawater, and seawater at 60 °C. These solutions significantly affected the impact properties. In this context, the maximum load, maximum displacement, and restored energy behaviour were studied to understand the influence of exposure time. It was possible to conclude that such impact parameters were significantly affected by the solutions, where the exposure time proved to be determinant. The benefits of cork on the perforation threshold were investigated, and this parameter increased when the epoxy matrix was filled with cork. Finally, cork filled epoxy laminates also show less variation in maximum load and recovered energy than carbon/epoxy laminates.

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