Percolation and Electrical Conductivity Modeling of Novel Microstructured Insulator-Conductor Nanocomposites Fabricated from PMMA and ATO

2014 ◽  
Vol 1692 ◽  
Author(s):  
Youngho Jin ◽  
Rosario A. Gerhardt
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Percolation Threshold ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Conductive Filler ◽  
Molding Pressure ◽  
Shape Transformation ◽  
Element Analysis ◽  
3D Network

ABSTRACTThe electrical conductivity of insulating polymer matrix composites undergoes radical increase at a certain concentration of conductive filler, which is known as the percolation threshold. Polymer matrix conductive nanocomposites were fabricated by compression molding the mechanically mixed poly (methyl methacrylate) (PMMA) and antimony tin oxide (ATO) nanoparticles, as has been done with other polymer composites before. The electrical conductivity of PMMA/ATO nanocomposites increased by several orders of magnitude at a small concentration of ATO (∼ 0.27 vol %). The continuous 3D network like distribution of ATO nanoparticles contributed to this percolation at subcritical filler concentrations. The effects of processing parameters on these unique microstructures and electrical properties were investigated. The tetrakaidecahedron-like microstructure was observed by scanning electron microscopy (SEM) and was found to be affected by the molding pressure, temperature and amount of nanoparticles. The viscoelastic flow of matrix under the optimum processing conditions allowed the shape transformation of PMMA into space filling polyhedra and an ordered distribution of ATO nanoparticles along the sharp edges of the PMMA. Parametric finite element analysis was performed to model this unique microstructure-driven percolation. The 2D simplified model was generated in AC/DC frequency domain mode in COMSOL Multiphysics® to solve the effects of ordered distribution of conductive nanoparticles on the electrical properties of the composite. There was excellent agreement between experimental and simulated values of electrical conductivity and percolation concentration. This model can be used to predict percolation threshold and electrical properties for any types of composite systems containing insulating matrix and conductive fillers that can form this unique microstructure.

UV Photopatternability and Electrical Properties of GnF/SU-8 Composites Controlled by GnF Concentration

2018 ◽  
Vol 765 ◽  
pp. 60-64
Author(s):  
Seung Pyo Woo ◽  
Sung Min Park ◽  
Gyung Mok Nam ◽  
Young Choi ◽  
Sang Heon Park ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Polymer Matrix ◽  
Material Properties ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Electrically Conductive ◽  
Screening Effect ◽  
Unique Material ◽  
Uv Dose

The GnF/SU-8 composites are new polymer matrix composites (PMCs) composed of graphite nanoflakes (GnFs) bound together by SU-8 photoresist. The PMCs therefore have excellent ultraviolet (UV) photopatternability and high electrical properties. In spite of the unique material properties of GnF/SU-8 composites, much still remains uncertain about their controllability in both UV photopatternability and electrical properties. Here, we investigate 7 kinds of GnF/SU-8 composites having different GnF concentrations of 5.0 to 25.0 wt.% to characterize the changes in the UV photopatternability (i.e., polymerized thickness and photopattern quality) and electrical conductivity of GnF/SU-8 composites caused by a variation in GnF concentration. The polymerized thickness of GnF/SU-8 composites is measured to be in the range of 4.06 to 23.99 μm, which is inversely proportional to GnF concentration and also directly proportional to UV dose (i.e., 345 to 3,450 mJ/cm2) because of the screening effect of GnF existed in the composites; the photopattern quality at the edge is in inverse proportion to GnF concentration. An increase in GnF concentration leads to a significant change in the electrical conductivity of GnF/SU-8 composites in a proportional way (up to 25.34 S/m). The GnF/SU-8 composites are expected to be widely used as UV photopatternable and electrically conductive PMCs for diverse engineering applications.

Effect of Processing on the Microstructure and Electrical Conductivity of Hot Pressed PMMA/ITO Bulk Nanocomposites

2006 ◽  
Vol 977 ◽  
Author(s):  
Charles J. Capozzi ◽  
Rosario A. Gerhardt
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Polymer Matrix ◽  
Indium Tin Oxide ◽  
Polymer Matrix Composites ◽  
Processing Parameters ◽  
Specimen Thickness ◽  
Matrix Composites ◽  
Matrix Nanocomposites ◽  
Network Microstructure

AbstractThere are few studies that discuss the effect of the fabrication conditions and bulk thickness on the electrical conductivity of hot pressed polymer-matrix composites. For polymer-matrix composites that possess a segregated-network microstructure, the processing parameters can significantly impact the electrical properties and microstructure of the composite material. Our group has recently fabricated novel polymer-matrix nanocomposites, which possess a segregated network microstructure containing regular, polyhedral-shaped polymer matrix particles1-2. This paper investigates the effect of processing pressure and specimen thickness on the electrical properties and microstructure of hot pressed poly(methyl methacrylate) (PMMA) containing segregated networks of indium tin oxide (ITO) nanopowders.

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 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.

Electrical conductivity of vapor-grown carbon fiber/thermoplastic composites

2001 ◽  
Vol 16 (6) ◽  
pp. 1668-1674 ◽  
Author(s):  
Ioana C. Finegan ◽  
Gary G. Tibbetts
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Carbon Fiber ◽  
Conducting Polymers ◽  
Radio Frequency ◽  
Percolation Threshold ◽  
Thermoplastic Composites ◽  
Radio Frequency Interference ◽  
Static Discharge

Conducting polymers are required for applications such as radio frequency interference shielding, primerless electrostatic painting, and static discharge. We have used vapor-grown carbon fiber (VGCF) as an additive to investigate conducting thermoplastics for these applications. The electrical properties of VGCF/polypropylene (PP) and VGCF/nylon composites are very attractive compared with those provided by other conventional conducting additives. Because of the low diameter of the VGCF used, the onset of conductivity (percolation threshold) can be below 3 vol%. Because of the highly conductive nature of the fibers, particularly after a graphitization step, the composites can reach resistivities as low as 0.15 Ω cm.

Overall Temperature-Dependent Elastic Properties of Carbon Fiber Polymer Matrix Composites at High Temperatures

2020 ◽  
Author(s):  
Teja G. K. Konduri ◽  
Olesya I. Zhupanska
Keyword(s):  
Carbon Fiber ◽  
Elastic Properties ◽  
Polymer Matrix ◽  
Volume Fraction ◽  
Polymer Matrix Composites ◽  
Type Equation ◽  
Temperature Dependent ◽  
Element Analysis ◽  
The Matrix ◽  
Pyrolysis Gases

Abstract In this paper we discuss the effect of volumetric ablation on the overall elastic properties of the carbon fiber reinforced polymer matrix composite. An Arrhenius type equation describing polymer decomposition was used to determine volume fractions of evolving polymer matrix phases (i.e. polymer, growing pores filled with pyrolysis gases, and char). The effect of the pressure exerted by pyrolysis gases trapped inside the pores was analyzed. Microstructures consisting of carbon fibers (circular inclusions) in the matrix and pores (elliptic inclusions) in the polymer were generated. Temperature dependency was addressed by generating microstructures with different volume fraction of pores, which were calculated from the mass loss model. Two-step numerical homogenization of representative volume elements (RVEs) was performed using finite element analysis (FEA). The developed procedures were applied to calculate temperature dependent (up to 700 K) effective elastic properties of the AS4/3501-6 composite. The results are compared to the existing experimental data and show good agreement.

Sign in / Sign up

Export Citation Format

Share Document