scholarly journals Dielectric Properties of Epoxy-Matrix Composites with Tungsten Disulfide Nanotubes

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Povilas Bertasius ◽  
Mark Shneider ◽  
Jan Macutkevic ◽  
Vytautas Samulionis ◽  
Juras Banys ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Epoxy Resin ◽  
Polymer Matrix ◽  
Epoxy Matrix ◽  
Electrical Contacts ◽  
Tungsten Disulfide ◽  
Electromagnetic Properties ◽  
Matrix Composites ◽  
Pure Epoxy ◽  
Electrical Percolation

Addition of conductive nanotubes to an insulating polymer matrix has been proven as an efficient strategy that can improve the electromagnetic shielding performance, due to the high aspect ratio of nanotubes. Herein, a set of epoxy-matrix composites filled with 0.15-1.6 vol% of tungsten disulfide (WS2) nanotubes being of 30-120 nm in diameter and 5-20 μm in length has been produced. Electromagnetic properties of the prepared composites were probed in the frequency range from 20 Hz to 1 MHz in a temperature range from 250 K to 500 K. Broadband properties of these materials are controlled by the dynamics of epoxy resin molecules, and no electrical percolation was observed up to the highest concentration (1.6 vol%) of WS2 nanotubes. The value of dielectric permittivity for all composites is not bigger than 6 at room temperature and 1 kHz frequency, and the electrical conductivity of composites is about 10-6 S/m at 500 K, which demonstrate that the composites are suitable for antistatic applications at higher temperatures. The relaxation time follows the Vogel-Fulcher law, and the Vogel temperature T0 has the minimum for the WS2 nanotube concentration 0.15 vol%. Above 410 K, the electrical conductivity determines the properties of the investigated composites due to nonzero electrical conductivity of epoxy resin. The value of DC electrical conductivity for pure epoxy at T=450 K is 0.3 μS/m, while the DC conductivity of the composites slightly increases with the WS2 concentration. Therefore, the electrical contacts between WS2 nanotubes and polymer matrix are rather ohmic. Additionally, the activation energy is almost independent on the concentration of WS2. However, it is higher in composites than in pure epoxy resin.

Effects of the Mould Pressure and Mould Pressing Time on the Properties of Graphite/Phenolic Resin Composites

2013 ◽  
Vol 706-708 ◽  
pp. 95-98
Author(s):  
Mi Dan Li ◽  
Dong Mei Liu ◽  
Lu Lu Feng ◽  
Huan Niu ◽  
Yao Lu
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Flexural Strength ◽  
Polymer Matrix ◽  
Phenolic Resin ◽  
Polymer Matrix Composites ◽  
Resin Composites ◽  
Matrix Composites ◽  
Natural Graphite ◽  
Pressing Time

Polymer matrix composites made from phenolic resin are filled with natural graphite powders. They are fabricated by compression molding technique. The density, electrical conductivity and flexural strength of composite are analyzed to determine the influences of mould pressure and mould pressing time on the physical, electrical and mechanical properties of composite. It is found that the density, electrical conductivity and flexural strength of composites increased with increasing mould pressure. Under pressure of 40 MPa for 60 min, the density, electrical conductivity and flexural strength of composites were 1.85 g/cm3, 4.35  103 S/cm and 70 MPa, respectively. The decreased gaps could be the main reason for the increasing of density, electrical conductivity and flexural strength as mould pressure increases. The results also show that the density of composites increased with increasing mould pressing time.

scholarly journals Broadband Dielectric Properties of Fe2O3·H2O Nanorods/Epoxy Resin Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Darya Meisak ◽  
Jan Macutkevic ◽  
Dzmitry Bychanok ◽  
Algirdas Selskis ◽  
Juras Banys ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Percolation Threshold ◽  
Epoxy Resin ◽  
Polymer Matrix ◽  
Finite Conductivity ◽  
Resin Composites ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold ◽  
Percolation Network ◽  
Properties Of Composites

A series of polymer composites based on epoxy resin with a 5–40 vol.% concentration of goethite (Fe2O3·H2O) nanorods was produced. The electrical percolation threshold in these composites was determined as 30 vol.% of nanorods. The dielectric properties of the composites both below and above the percolation threshold were studied in a wide temperature (200 K–450 K) and frequency (from Hz to THz) ranges. The dielectric properties of composites below the percolation threshold are mainly determined by the relaxation in a pure polymer matrix. The electrical properties of composites above the percolation threshold are determined by the percolation network, which is formed by the goethite nanorods inside the polymer matrix. Due to the finite conductivity of the epoxy resin, the electrical conductivity at high temperatures occurs in the composites both above and below the percolation threshold.

scholarly journals A Numerical Study on Electrical Percolation of Polymer-Matrix Composites with Hybrid Fillers of Carbon Nanotubes and Carbon Black

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yuli Chen ◽  
Shengtao Wang ◽  
Fei Pan ◽  
Jianyu Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Electrical Percolation ◽  
Hybrid Fillers ◽  
Nonlinear Relation ◽  
Electrical Percolation Threshold

The electrical percolation of polymer-matrix composites (PMCs) containing hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.

Fracture Mechanisms in Fiber Reinforced Polymer Matrix Composites

2014 ◽  
Vol 1611 ◽  
pp. 153-158
Author(s):  
C. Rodríguez ◽  
M. Hinojosa ◽  
J. Aldaco ◽  
A. Cázares
Keyword(s):  
Carbon Fibers ◽  
Matrix Composite ◽  
Polymer Matrix ◽  
Epoxy Matrix ◽  
Polymer Matrix Composites ◽  
Glass Fibers ◽  
Fracture Mechanisms ◽  
Matrix Composites ◽  
Polyester Matrix ◽  
Epoxy Matrix Composite

ABSTRACTIn this work we report the fractographic study of polymer matrix composites specimens reinforced with glass and carbon fibers. Specimens of a polyester matrix composite with 30% of E-glass fibers are prepared and fractured in flexure mode. We also test an epoxy matrix composite with 30% carbon fibers, which is fractured in flexure mode. All specimens are manufactured based on the D790 ASTM standard for bending mode at room temperature. As an exception, the composites with epoxy matrix and reinforced with carbon fiber are cured in an autoclave. The most commonly observed fracture mechanisms are debonding in the interphase, delamination, Chevron lines, microbuckling, river patterns and radial fracture on the fibers.

scholarly journals Improving Mechanical Properties of Thermoset Biocomposites by Fiber Coating or Organic Oil Addition

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Truc T. Ngo ◽  
James G. Kohl ◽  
Tawni Paradise ◽  
Autumn Khalily ◽  
Duane L. Simonson
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Epoxy Resin ◽  
Polymer Matrix ◽  
Modulus Of Elasticity ◽  
Epoxy Matrix ◽  
Linseed Oil ◽  
Hemp Fibers ◽  
Fiber Coating ◽  
Strength And Ductility

Two different thermoset biocomposite systems are experimented in this study with the hope to improve their mechanical properties. Fiberglass and hemp, in form of fabrics, are used to reinforce the thermoset polymer matrix, which includes a traditional epoxy resin and a linseed oil-based bioresin (UVL). The fiber/polymer matrix interface is modified using two different approaches: adding a plant-based oil (pine or linseed) to the polymer matrix or coating the fibers with 3-(aminopropyl)triethoxysilane (APTES) prior to integrating them into the polymer matrix. Epoxy resin is cured using an amine-based initiator, whereas UVL resin is cured under ultraviolet light. Results show that hemp fibers with APTES prime coat used in either epoxy or UVL matrix exhibit some potential improvements in the composite’s mechanical properties including tensile strength, modulus of elasticity, and ductility. It is also found that adding oil to the epoxy matrix reinforced with fiberglass mostly improves the material’s modulus of elasticity while maintaining its tensile strength and ductility. However, adding oil to the epoxy matrix reinforced with hemp doubles the material’s ductility while slightly reducing its tensile strength and modulus of elasticity.

Preparation and Mechanical Characterization of a Polymer-Matrix Composite Reinforced with PET

2010 ◽  
Vol 1276 ◽  
Author(s):  
J. Elena Salazar–Nieto ◽  
Alejandro Altamirano–Torres ◽  
Francisco Sandoval–Pérez ◽  
Enrique Rocha–Rangel
Keyword(s):  
Epoxy Resin ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Mechanical Tests ◽  
Polymeric Matrix ◽  
High Porosity ◽  
Matrix Composites ◽  
Curing Time ◽  
Flexure Strength

AbstractIn this study, polymer-matrix composites are fabricated by mixing liquid epoxy resin with 0, 15, 20 and 25 wt % of PET. PET is used as a reinforcement material since it can be recycled and this implies a beneficial environmental impact. After mixing, specimens are dried at room temperature during 24 h and then cured at 150°C during 0.5, 0.75 and 1 h. Then mechanical tests are performed. Experimental results obtained from the flexion test for 100 % epoxy resin and 15 % PET samples, without curing treatment show values of 30 and 21 MPa, respectively. Flexure strength values for the same samples but after curing treatment are: 56, 90, 32 MPa and 69, 64, 70 MPa, for 0.5, 0.75 and 1 h of treatment, respectively. These data show an important increase in the flexure strength for the sample reinforced with 15 % PET and curing time of 1h. This is most likely due to the behavior of PET's powders at this temperature and time. They can partially melt improving the adhesion to the polymeric matrix. For a curing time of 0.75h, this property decreases, due to the high porosity developed in the composite and the poor adhesion between polymeric matrix and reinforced material.

Morphology and Properties of Carbon Nanotubes Modified Epoxy

2011 ◽  
Vol 284-286 ◽  
pp. 918-922
Author(s):  
Xiao Lan Hu ◽  
Wen Hao Wang ◽  
Rong Lu Yu ◽  
Gang Liu ◽  
Teng Fei Lu
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Properties ◽  
Epoxy Resin ◽  
Optical Microscopy ◽  
Epoxy Matrix ◽  
Amino Group ◽  
Matrix Composites ◽  
Elementary Analysis ◽  
Nanotube Dispersion ◽  
Modified Epoxy

Multi-walled carbon nanobutes (MWNTs) reinforced epoxy resin nanocomposites were fabricated by functionalizing the MWNTs with amino group. The functionlization of MWNTs was characterized by FTIR, elementary analysis, and TEM, and the MWNTs dispersion was characterized by optical microscopy and SEM. MWNTs functionalization with ethylene diamine improved the nanotube dispersion in the epoxy matrix composites. The dynamic mechanical thermal properties and thermal properties of MWNTs/epoxy nanocomposites are briefly discussed in terms of the MWNT loading and dispersion.

scholarly journals UV Sensor Based on Fiber Bragg Grating Covered with Graphene Oxide Embedded in Composite Materials

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5468
Author(s):  
Piotr Lesiak ◽  
Karolina Bednarska ◽  
Krzysztof Małkowski ◽  
Łukasz Kozłowski ◽  
Anna Wróblewska ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Epoxy Resin ◽  
Fiber Bragg Grating ◽  
Uv Radiation ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Glass Fibers ◽  
Fiber Optic Sensor ◽  
Bragg Grating ◽  
Matrix Composites

Polymer–matrix composites degrade under the influence of UV radiation in the range of the 290–400 nm band. The degradation of polymer–matrix composites exposed to UV radiation is characterized by extensive aging of the epoxy matrix, resulting in deterioration of their mechanical properties. Glass fibers/epoxy resin composites were made by an out-of-autoclave method whereas a fiber optic sensor was placed between different layers of laminates. In our work, we used a fiber Bragg grating sensor covered with graphene oxide and embedded in a polymer matrix composite to monitor UV radiation intensity. Measurements of UV radiation may allow monitoring the aging process of individual components of the polymer composite. In order to estimate the number of microcracks of epoxy resin, microstructure observations were carried out using a scanning electron microscope.

scholarly journals Review of Polymer Composites with Diverse Nanofillers for Electromagnetic Interference Shielding

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 541 ◽  
Author(s):  
Dimuthu Wanasinghe ◽  
Farhad Aslani ◽  
Guowei Ma ◽  
Daryoush Habibi
Keyword(s):  
Electrical Conductivity ◽  
Polymer Composites ◽  
Polymer Matrix ◽  
Electromagnetic Interference ◽  
Polymer Matrix Composites ◽  
Morphological Properties ◽  
Matrix Composites ◽  
Emi Shielding ◽  
Alternative Materials ◽  
Metallic Panels

Polymer matrix composites have generated a great deal of attention in recent decades in various fields due to numerous advantages polymer offer. The advancement of technology has led to stringent requirements in shielding materials as more and more electronic devices are known to cause electromagnetic interference (EMI) in other devices. The drive to fabricate alternative materials is generated by the shortcomings of the existing metallic panels. While polymers are more economical, easy to fabricate, and corrosion resistant, they are known to be inherent electrical insulators. Since high electrical conductivity is a sought after property of EMI shielding materials, polymers with fillers to increase their electrical conductivity are commonly investigated for EMI shielding. Recently, composites with nanofillers also have attracted attention due to the superior properties they provide compared to their micro counterparts. In this review polymer composites with various types of fillers have been analysed to assess the EMI shielding properties generated by each. Apart from the properties, the manufacturing processes and morphological properties of composites have been analysed in this review to find the best polymer matrix composites for EMI shielding.

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