2005 Volume 52 Issue 1 Pages 5-13
In order to obtain the basic data in cracking of PE, PP and PS (addition polymerization plastics), experimental investigation was carried out using supercritical water of density of 0.3 g/cm3 at a temperature of 430°C and a pressure of ca. 42 MPa.
It was found that these plastics were easily decomposed to oily materials without coke formation and the time required for liquefaction was in the order of PE>PP>PS. The oily products obtained had the main chemical structure of polymers; normal paraffin's for PE, and 1,3,5-cyclohexane for PP. For PS, styrene monomer was first produced, with a gradual increase in ethyl benzene toluene and stable poly-phenyl hydrocarbons with 2-4 rings, which were different, from oligomer of styrene. The amount of them increased with reaction time. When a decomposition reaction occurred in alkali solution, the decomposition rate decreased, but the reaction mechanism seemed to be unchanged.
