Estimation of flocculation structure in filled polymer composites by dynamic rheological measurements

Citation
G. Wu et al., Estimation of flocculation structure in filled polymer composites by dynamic rheological measurements, COLLOID P S, 278(3), 2000, pp. 220-228
Citations number
33
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
COLLOID AND POLYMER SCIENCE
ISSN journal
0303-402X → ACNP
Volume
278
Issue
3
Year of publication
2000
Pages
220 - 228
Database
ISI
SICI code
0303-402X(200003)278:3<220:EOFSIF>2.0.ZU;2-R
Abstract
The frequency and concentration dependences of the storage modulus (G') for carbon black and short-carbon-fiber-filled polymer composites were investi gated by means of dynamic rheological measurements. It was found that G' at low frequencies and amplitudes could be used as a sensitive experimental p arameter for detecting the flocculation structure of the ultra-fine-particl e-filled polymer composites. Correlation of electrical resistivity of the c omposites to the relative storage modulus, G(r)'(= G(c)'/G(p)'), revealed t hat the three-dimensional interparticle networks start to construct through the matrix when G(r)' increases to 7 regardless of the composite systems. Quantitative calculations in order to determine the flocculation structure were carried out by means of the modified Kerner equation. A plot of the ca lculated value, defined as the floc index A, dependence of electrical resis tivity for various systems was found to be a universal curve. Accordingly, we suggest that A might universally correspond to the flocculation structur e of the filler, which is independent of the nature of the filler, the mole cular weight, the chemical composition of the polymer and the temperature a t which the measurement is made. This method is particularly effective for estimating the flocculation structure of ultra-fine-particle-filled polymer composites no matter whether the filler is conductive or not.