Adding small amounts of clay to polymer resins, results in
improvement in multiple properties. The key to improving performance
is that the clay undergo exfoliation during compounding with
the resin, so that nano size silicate flakes are dispersed throughout
the resin. The NIST dielectric slit die was designed for the
purpose of using macroscopic measurements, such as dielectric
relaxation spectroscopy and optical transmission, to deduce
information about the microstructure of polymer/clay composites.
Utilizing real-time measurements to describe microstructure
replaces time consuming off-line measurements such as TEM and
X-ray.
Experimental Approach
NIST Dielectric Slit Die - Side View
Optical Sensor (for measuring light transmission)
Results
Maxwell Wagner Relaxation
Reflects RC Time Constant for Charging Polymer/Clay
Interface
Light Attenuation
The Universal Exfoliation Scale
C is
capacitance of the silicate clay particles which increases
with exfoliation. q is the ionic charge, a is the size of the
ion and
n is viscosity of the resin. The expression shows the relationship
between the time to charge the interface capacitance tMW and
the viscosity of the resin.
Publications
“In-Line Monitoring of Dielectric and Fluorescence Spectroscopy
During Polymer/Filler Compounding”, A. J. Bur, S. C.
Roth, Y-H. Lee, M. McBrearty, Polymer, Rubber & Composites
33, 5 (2004).
“A Dielectric Slit Die for In-Line Monitoring of Polymer
Compounding” A.J. Bur, S.C. Roth, Y-H. Lee, M. McBrearty,
Rev. Sci. Instrm. 75, 1103 (2004).
Contributors:
Anthony J. Bur*
Yu-Hsin Lee
Steven C. Roth
Paul R. Start
Michael McBrearty, Chemical ElectroPhysics
Processing Characterization Group
Polymers Division
Materials Science and Engineering Laboratory
