Accurate Measurement of PVT Data for PP/Gas and TPO/Gas Mixtures 2006-01-0506
Foaming of a thermoplastic polyolefin (TPO) is gaining interests because of its superior mechanical properties of foamed automotive parts, such as lightweight and high performance to weight ratio, etc. In this context, understanding of the thermophysical properties of PP/gas and TPO/gas mixtures is critically important. This paper will present the newly developed experimental technique to accurately measure the swelling of PP and TPO due to gas dissolution at elevated temperatures and pressures.
Our technique measures the geometry of the pendent drop accurately from the captured images to obtain the volume swelling data. It determines the boundary location of the polymer/gas sample accurately by magnifying the sample drop locally along its edge before capturing the image. The automated high-precision XY stage is chosen as the platform to control the motion of the CCD camera. Those images are reconstructed into one big image in the virtual domain based on the original pixel coordinates from individual images. By applying the curve fitting and integration technique, we finally determine the volume swelling of the PP/gas and TPO/gas mixtures.