Thermal Decomposition Kinetics of Functionalized Polynorbornene

The mechanism and kinetic parameters for the thermal decomposition of four functionalized addition-polymerized polynorbornenes were studied by dynamic and isothermal thermogravimetric analyses and by mass spectrometry. The dynamic and isothermal thermogravimetric analyses showed a first-order degradation reaction mechanism with an activation energy of 229.6 ± 12.5 kJ/mol. Based on the polymer structure, reference mass spectra for related molecules, and a cross-comparison of the mass spectra, the backbone, free-radical scission mechanism was found to occur by cleavage of the linkages between bicyclic rings and the production of volatile monomer and oligomers. The degradation of polynorbornene occurred via a depropagation and transfer reaction process. Initially, the depropagation pathway was preferred, but with increasing conversion, intra- and intermolecular hydrogen transfer reactions dominated.