Thermal degradation of polyethylene

Thermal degradation of polystyrene, poly(1,4-butadiene) and copolymers of styrene and 1,4-butadiene irradiated under air or argon with 60Co-γ-rays

“…8 respectively, exhibited both endo-and exothermic features, the latter very likely reflecting the discontinuity in the TGA curves. The difference in the thermal stability and in the course of the decomposition of the two homopolymers observed in this work is well known and in this connection credit has to be given to earlier work concerning the thermal degradation of PBD 11,12,13,14,15,16 , of PSt 17,18,19,20,21,22,23,24,25 and PBD-PSt copolymer. 26,27 3.2.…”

“…Since oxic irradiation does not generate crosslinks but also causes a shift in the TGA curve to higher temperature, it can be excluded that radiation-induced intermolecular crosslinks are responsible for the observed increase in the heat resistance of PSt. On the other hand, it has been reported that 60 Co-γ-irradiation generates carbon-carbon double bonds in PSt 4,19 and there are two modes of action to be considered in this connection: (a) unsaturated groups can scavenge free radicals generated by main-chain scission and thus inhibit or retard the depolymerization, and (b) the presence of unsaturated groups in the polymer can bring about thermally induced crosslinking reactions that otherwise would not occur. The two modes of action might be strongly interdependent if the free radical formed by the reaction of a terminal macroradical with a carbon-carbon double bond initiates the coupling of unsaturated groups.…”

Pyrolysis of polyolefins in high-boiling solvents

“…The composition of the main products of PE pyrol ysis-saturated hydrocarbons and olefins-strongly depends on the process conditions -(temperature, pressure, process duration, heating rate, and reactor type) [3,4,[8][9][10][11][12][13].…”