Development of a universal sample controlled thermal analysis (SCTA) system for being used with any thermoanalytical instrument

Abstract

The SCTA method implies to control the te mperature in such a way that the reaction rate changes with the time according to a function previously defined by the user. Constant Rate Thermal Analysis (CRTA) is one of the most commonly used SCTA methods and implies achieving a temperature profile at whic h the reaction rate remains constant all over the process at a value previously selected by the user. This method permits to minimize the influence of heat and mass transfer phenomena on the forward reaction. The scope of this work is to develop a universal CRTA temperat ure controller that could be adapted to any thermoanalytical device. The thermoanalytical signal is programmed to follow a preset linear trend by means of a conventiona l controller that at the time controls a second conventional temperature programmer that forces the temp erature to change for achieving the trend programmed for the thermoanalytical signal. Ex amples of the performa nce of this control system with a Thermobalance and a Thermomechanical Analyser (TMA) are given.