Conducting and Antistatic Composites for Space Applications
- PDF / 95,143 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 62 Downloads / 242 Views
NN8.11.1
Conducting and Antistatic Composites for Space Applications Mircea Chipara1, Jagannathan Sankar2, Petre Notinger5, Denis Panaitescu6, David Hui3, Gheorghe V. Aldica6, Magdalena D. Chipara1, and Kin-tak Lau4 1
Indiana University Cyclotron Facility, Indiana University, Bloomington, Indiana Department of Mechanical Engineering, North Carolina A&T State University, Greensboro, North Carolina 3 Department of Mechanical Engineering, University of New Orleans, New Orleans, Louisiana 4 Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, Hong Kong 5 Politehnica University, Bucharest, Romania 6 National Institute for Materials Physics, Bucharest, Romania 2
ABSTRACT The percolative dependence of the DC conductivity on the volume concentration of fillers for composites obtained by dispersing conducting particles into polymeric matrices is studied in detail. An empirical Boltzmann like dependence is proposed for the modeling of the dependence of DC conductivity versus filler concentration. This expression allows for a more accurate determination of the percolation threshold in the case of broad percolations. It is shown that the loading of the polymeric matrices with conducting fillers produces percolative-like changes of various physical properties (such as the reciprocal of the tensile strength and the reciprocal of the double integral of the resonance spectrum). Experimental mechanical, electrical, and electron spin resonance data on polyvinylchloride-carbon, polyvinylchloride-polyaniline, and polyethylene-polyaniline composites are reported.
INTRODUCTION Conducting polymers (CPs) are of particular interest for space applications due to their high conductivity (in heavily doped forms) and lightweight. The most important applications of CPs - of relevance to space exploration - are: electro-magnetic interference shielding, lightweight conductors, antistatic coatings, rechargeable batteries, gas separation membranes, and actuators (artificial muscles). CPs exhibit either good mechanical properties and poor thermal/thermo-oxidative stability (such as polyacetylenes) or good thermal/thermo-oxidative stability and poor mechanical features (such as polypyrrole and polyaniline). Some CPs with high DC conductivities such as polyaniline (PANI) and polypyrrole (PPY) have rather poor processability. From the technological point of view, both the processability of CPs and their thermal stability are important issues. Several research directions were developed to overcome these drawbacks. One is focused on the chemical functionalization of CPs. The other research direction emphasizes the synthesis of new CPs with improved physical and chemical
NN8.11.2
properties. The most advanced research direction aims at composites obtained by dispersing highly conducting CPs with excellent thermal and thermo-oxidative stability (such as PANI and PPY) in polymeric matrices with outstanding mechanical properties. For space applications, this approach presents a particular importance as it may result in
Data Loading...
