Pyrolysis study of polyurethane

The thermal decomposition of a polyurethane in an inert atmosphere has been studied. Three different apparatus, a thermobalance, a pyroprobe and a laboratory furnace, were use to study the kinetics of decomposition and the evolution of gas and volatiles. The kinetics were studied using a thermobalance and four heating rates. The experimental results were described satisfactorily by a two parallel reaction models. The kinetic parameters, that is, the pre-exponential factors, activation energies, reaction orders and maximum production of volatiles at infinite time were also obtained. The formation of hydrocarbons at different nominal temperatures was studied using a coil pyroprobe. An increase of the yield of light hydrocarbons (methane, ethylene, etc) was observed as the pyrolysis temperature increased. The secondary products from the formation/cracking reactions of the different primary compounds were identified by passing the pyrolysis products through a furnace prior to detection. The recovery of chemicals from the pyrolytic degradation was then studied. Toxic compounds were determined by carrying out thermal degradation in a Nitrogen atmosphere. Gas chromatography/mass spectrometry (GS/MS) was used to identify volatile and semivolatile organic compounds generated by the thermal degradation reactions. (C) 2001 Elsevier Science B.V. All rights reserved.