Thermometric behavior of polyolefins

Yield and Composition of Gases and Oils/Waxes from the Feedstock Recycling of Waste Plastic

“…However, Kaminsky et al [9], using higher temperatures of pyrolysis, found increased concentrations of methane compared with fixed-bed pyrolysis [7]. The thermal degradation of polyalkenes has been described as a random scission process whereby during degradation the rupture of bonds takes place at purely random points along the polymer chain length [29,30]. Thus, all the bonds which remain intact at any one stage in the degradation process have the same probability of being broken, leading to the formation of polymer fragments of varying sizes.…”

Catalytic Upgrading of Plastic Wastes

“…As a consequence of this mechanism, thermal cracking of polyethylenes leads towards a broad distribution of hydrocarbons within the C 5 -C 80 range, each fraction being mainly formed by the corresponding diene, 1-olefin and n-paraffin, as it can be appreciated in the gas chromatogram shown in Figure 3.2. At high temperature, hydrogen is also formed in significant amounts [15]. The products of thermal cracking of polyolefins are of limited commercial value, being mainly applied as fuels.…”

“…In terms of mechanism, thermal degradation proceeds according to a radical chain reaction pathway comprising hydrogen transfer steps along with the progressive breaking of the polymer backbone. The detailed mechanism can be found elsewhere and involves the classical initiation, propagation and termination steps [4,15]. In general terms, the initiation reactions comprise the homolytic cleavage of a carbon-carbon bond by either random or end chain scission giving rise to the appearance of two radicals.…”

Interaction between Polyethylene and Petroleum Coke Substrate during Pyrolysis

“…The mechanism of polyethylene degradation has been explained in a number of studies [12][13][14]. The degradation step is initiated by random scission reaction.…”