Polymer reactions—Part VII: Thermal pyrolysis of polypropylene

Numerical Study of Radiation Effects on Polypropylene Combustion Using High-temperature Oxidizer Diluted with H2O and CO2

“…In this model, as shown by Eq. (14), the local volumetric rate of radiative heat loss calculated using OTM is evaluated using the temperature of the PP surface, the local temperature in the gas phase, and the temperature of the oxidizer. (13).…”

“…In this study, the kinetic parameters of the thermal pyrolysis were taken from the experimental data by Kiang et al [14] since they are close to the average of other experimental data. Actually, there are no experimental data of PP pyrolysis under the peculiar conditions of HiTAC.…”

Composition of Liquid Fuels Derived from the Pyrolysis of Plastics

“…The slight positive deviation of peak heights from a statistical distribution of the hydrocarbon homologous series of 1-alkenes at C 6 , C 7 , C 10 , C 11 , C 14 , C 15 C 18 , C 19 is due to the superposing contribution of backbiting of the primary macroradical in to its own chain at preferred carbon atoms due to the conformation of the polymer coil in the melt [23]. Note that the higher-molecular-mass section of the product distribution is missing in the pyrogram because the given GC conditions are not satisfactory for the analysis of the components over C 28 . In a mass spectrometer (under vacuum) the distribution has been reported [24] to go up to C 50 .…”

“…The observed pyrolysis product distribution of PP is developed by a free radical mechanism [28,29] which begins with the homolytic breakage of the polymer chain drawn in Scheme 12.3 where X represent a methyl group in this case. Primary macroradical 1 is formed only in the initial step, thus its decomposition plays a minor role in PP.…”

“…A bulky substituent such as the phenyl group in PS may hinder the intermolecular radical transfer by shielding the easily abstractable hydrogen atoms [31] while at the same time a phenyl group is able to give a higher stability to the secondary macroradicals by resonance over the aromatic ring. The secondary macroradical plays the main role in the pyrolysis process of several vinyl polymers [19,28] which is either depolymerized to monomer or transferred to the third and fifth carbon atom from the radical end of the macromolecule evolving dimer and trimer after β-scission, respectively, reproducing the secondary macroradical in a chain reaction as drawn in Scheme 12.4. The β-scission may also proceed in the other direction along the macroradicals, leading to small radicals and vinyl-terminated macromolecules in this case.…”