Thermal decomposition of low-density polyethylene in the presence of iron and copper chlorides

Abstract

The effects of iron and copper chlorides on the pyrolysis products of low-density polyethylene were studied using Py-GC/MS for the analysis of volatiles, and FT-IR spectroscopy for the pyrolysis tars. The presence of Fe(II) and Cu(I) chlorides initiates chain scission at the early stage of polyethylene thermal decomposition, producing increased amounts of olefin bonds at 400 °C. In the presence of iron and copper chlorides, chlorobenzene and chloronaphthalene are formed from polyethylene at 600 °C. Considerably more chlorobenzene is produced with Cu(II) chloride than with iron chlorides, and the chlorination is similarly efficient also with Cu(I) chloride at 1000 °C. The amounts of aromatic volatiles are greatly increased by Cu(II) and Fe(III) chlorides at 600 °C. However, at 1000 °C, the amounts of light aromatics are slightly reduced and the char production is favored by the presence of anhydrous iron and copper chlorides of a higher oxidation state.