ISSN:
0887-6266
Keywords:
dielectric spectroscopy
;
interfacial polarization
;
Debye length
;
particle size
;
polymer blends
;
laminates
;
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
In this article we will focus on the dielectric properties of laminates and blends of a partially conducting (the liquid crystalline copolyesteramide Vectra B950) and an insulating (polypropylene or mica) phase. Dielectric spectroscopy was used as a tool to obtain information about the influence of the dimensions of the conducting phase in these laminates and blends. With decreasing thickness of the conducting layer in the laminates, the measured permittivities deviate more and more from the values predicted using conventional dielectric mixture models. From this discrepancy it is possible to calculate the thickness of the charge layer (=Debye length) in the conducting phase and the thickness of this phase itself, using a model derived by Trukhan. This model incorporates not only conduction, but also diffusion of the charges. Similar experiments were performed on a system of Vectra B950 particles in a polypropylene matrix. After the derivation of a new model, which combines the Trukhan model for space charges with the Böttcher equation for dielectric mixtures, we could make a distinction between samples containing large and small particles. For samples containing small particles, it is even possible to determine the variation in particle sizes. However, the use of a Debye length of 1.1 µm obtained from the laminates resulted in particle sizes that were two times higher than the actual values. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2835-2848, 1998
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
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