Effects of Temperature and Concentration on the Rheological Properties of Acrylonitrile-Butadiene-Styrene Polymer Solutions and Melts

Abstract

Acrylonitrile-Butadiene-Styrene (ABS) is a ubiquitous polymer used throughout industry. The rheological properties of ABS are extremely important to know if one is designing a system that will extrude the polymer into various shapes, as it can help in determining what temperature the polymer should be, or how much force must be applied to the polymer to force it through a die. ABS is manufactured and processed in volatile solvents at high temperature and pressure. Thus, its rheological properties, or a measurement of how easily it flows, are highly sought after information. The rheological properties of ABS at 25 degrees Celsius and 1 atmosphere are well known. However, industry often requires for the temperature and pressure to be much higher, at around 100 atmospheres and 50-100 degrees Celsius, and concentrations varying from 40 to 70 weight percent. Solvents often used to synthesize ABS are also quite volatile; that is, they vaporize easily, which is only exacerbated by the high temperatures required, as the high temperatures cause the already volatile solvents to vaporize more easily at higher temperatures. This research seeks to quantify the rheological properties at high temperatures and at various concentrations. In order to determine the properties, a unique high-pressure rheometer will be used. The rheometer exerts a torque on the liquid at various shear rates, and measures the resistive force the liquid exerts on the rheometer to calculate viscosity. The rheometer also allows a pressure to be put over the polymer, which assists in preventing the solvent from vaporizing. The results obtained will be compared to theoretical models that require pressure, temperature, concentration, and molecular weight as input.