SIMPLE ESTIMATION OF THE TEMPERATURE ERROR IN THERMOGRAVIMETRIC EXPERIMENTS

Two simple expressions are presented for the calculation of the maximum temperature difference between the centre and the outer boundary of a sample during a temperature-programmed TG experiment. The results obtained using these formulae are compared with those obtained with a classical heat transfer/chemical reaction model of a devolatilization reaction. The formulae give an excellent estimate of the maximum temperature difference for endothermic and athermic reactions (if this difference does not exceed ~ 30 ° C) and for exothermic reactions (if it does not exceed ~ 8 ° C). Above these values, although inaccurate, the approximate formulae may still be useful in warning of large temperature errors in a TG experiment. © 1990.