The relationship of carbon black dispersion to electrical resistivity and vulcanizate physical properties

Abstract

The degree of dispersion of carbon black in rubber is known to be a determining factor in the physical properties of the composite. It is important, therefore, to have a reliable, quantitative technique for assessing carbon black dispersion. It has been known for some time that the degree of dispersion of carbon black is reflected in its electrical resistivity. A resistivity instrument, developed by B. Boonstra, has been redesigned and constructed for use in this study. Factors that influence resistivity (i.e., black type, volume loading, and mixing time) are examined. Physical property and dynamic mechanical measurements are made, and their relationship to black dispersion is investigated. Light microscopy is also used to evaluate dispersion, and these data are compared to the resistivity results.

Synthesis of ZnO Nanorods by Laser Ablation of ZnO and Zn Targets in He and O2 Background Gas

“…At higher volume fractions, the electrical conductivity of the composites was not seen to change appreciably with mixing. The behavior that the mixing quality increases as the electrical resistivity first increases, reaches a peak and then drops off, has been observed previously with high-structure carbon-black-polymer composites [25]. The mechanism for this behavior was described by [26] as a natural consequence of shear mixing that leads to (1) smaller size of filler particle aggregates, enhancing the formation probability of conductive networks (2), higher dispersion homogeneity and (3), poorer conductive behavior due to structure breakdown.…”

Carbon black filled conducting polymers and polymer blends

“…(5) depends on mixing time, which is unique in itself and predicts a decrease of V f when time increases. This can explain the change of conductivity with mixing time 40 or heating time 46 as previously reported.…”

“…In a study by Cembrola 40 two CBs with different structure were compounded with styrene-butadiene rubber (SBR) and the effect of mixing time was studied. The mixing affected not only the electrical conductivity, but also mechanical properties.…”

Temperature and time dependence of conductive network formation: Dynamic percolation and percolation time

“…The dispersion state of conductive particles in a host polymer affects the final electrical properties [1][2][3][4][5][6][7][8][9][10][11][12][13]. To understand the conductive network formation, percolation theory has been used to describe the relationship between the electrical conductivity and the filler content [14,15].…”