Advances in Filler Dispersion Measurements

Abstract

It is well documented throughout the literature that filler dispersion significantly influences rubber performance. However, there is no single experimental method to measure dispersion precisely. By presenting new experimental techniques and reviewing several existing ones that measure dispersion at different length scales, steps are undertaken to close the knowledge gap in understanding dispersion. Some methods, such as electrical resistivity, are able to probe only the conductive carbon black network; the others take into consideration all compounding ingredients including mineral fillers and chemicals. One of the techniques discussed in more detail will be surface profilometry, which is based on the noncontact optical interferometry principle. The other technique reviewed in more detail is based on high-resolution field emission scanning electron microscopy imaging. These different techniques were employed to evaluate multiple rubber compounds with varying dispersion levels, and the data will be presented and discussed.

Mixing time influence on fatigue crack growth in a carbon black-filled natural rubber vulcanizate

“…8 Since the interaction between CB and rubber is mainly physical, enhancement of surface interaction ensures adequate dispersion. Dispersion can be assessed by qualitative judgement such as visual inspection and quantitative assessment by microscopy, 9 dispergrader study, 10 electrical conductivity 7 and thermal conductivity. 11…”

“…Even though the addition of CB results in improved performance properties, undispersed filler particles, that is, agglomerates, act as a flaw. [5][6][7] For instance, any agglomerate above the size of 0.01 mm can act as a flaw in a system. 8 Since the interaction between CB and rubber is mainly physical, enhancement of surface interaction ensures adequate dispersion.…”