THE THERMAL-STABILITY OF POLYETHERIMIDE

A technique called bivariate fitting has been devised for obtaining kinetic parameters of thermal decomposition of polyetherimide from TGA data. In this way an apparent order of 5 multiplied by (times) 33 was obtained, an apparent activation energy of 192kJ/mol, and a pre-exponential factor of 1 multiplied by (times) 45 multiplied by 10**1**2 min** minus **1. Compared with other methods this method was found to be a good approach to the solution of the kinetics of the decomposition. The products of the thermal degradation of the polymer were also analyzed by ir, elemental analysis and pyrolysis/gas chromatography/mass spectrometry. A decomposition mechanism is suggested.