A Computer Method for the Thermogravimetry of Ablative Plastic Materials. Empirical Kinetics and Thermogram Construction.

摘要

In constant heating rate thermogravimetry experiments, a material is heated at a constant rate of temperature change. A thermogram of weight versus temperature is simultaneously recorded. The weight of a polymer during pyrolysis was represented by a kinetic equation of the Arrhenius form. The three empirical kinetic parameters for this equation were derived from a novel computer program using the experimental thermogram. A magnetic tape was also produced in a separate operation for a CalComp plotter. The plotter reconstructs the thermogram for the evaluation of any calculational error and comparison with previous results or theory. The report reviews the primary computer code (TRIM) which is used to calculate the empirical kinetic parameters from the integral weight and temperature values derived from the experimental thermogram. The magnetic tape/plotter subroutine (PAR-3) is then discussed in detail. This subroutine constructs a thermogram from parameters generated by the code (TRIM). An analysis was made for a polyimide resin run at four rates of heating for purposes of illustration. Calculated and experimental residual weights were compared at selected temperatures. (Author)