No abstract

This paper demonstrates a low-cost, high-performance thermocouple homogeneity scanner based on a pressure-controlled water heatpipe that is open to the atmosphere. With this arrangement, very much like a steam-point apparatus, the atmosphere provides the controlled pressure and the buffer gas for the heatpipe, and the isothermal zone is close to 100 • C. The thermocouple is inserted into the steam within the heatpipe through a plastic membrane so that the gradient is imposed over a spatial region determined primarily by heat flow within the thermocouple body, and can be as small as a few millimeters. The paper explains the construction of the scanner, and presents results of example scans demonstrating the uniformity and resolution of the scanner.

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.