Investigation of not fully stable fluids by the method of controlled pulse heating. 4. Evaluation of PMMA thermophysical properties up to 673 K

Publication date: Available online 23 September 2019Source: Thermochimica ActaAuthor(s): Aleksandr A. Starostin, Kirill V. Luk’yanov, Aleksandr A. Smotritskiy, Pavel V. SkripovAbstractIt has been shown that it is possible, in principle, to evaluate a set of the thermophysical properties of a polymer using a single high-power heating pulse over a wide temperature range including the region of states superheated with respect to the temperature of thermal decomposition onset in a quasi-static process. The corresponding research tool consists of the experimental method of controlled pulse heating of a fast-response wire probe with a characteristic measurement time of 10-3 s combined with a numerical method for assessing the temperature dependencies of the thermophysical properties from the experimental thermal response to the heat pulse. The evolution of the probe temperature at a given heating power was derived on the basis of primary data; namely, voltage drops on the probe and standard resistor in the course of heat release. A numerical procedure based on the model of optimising the heat conduction parameters has been constructed using genetic algorithms. The most probable temperature dependencies of the thermal conductivity and volumetric heat capacity for a polymethyl methacrylate (PMMA) sample have been determined in the range 300–673 K.

Source: Thermochimica Acta - September 24, 2019 Category: Chemistry Source Type: research