THERMAL-DECOMPOSITION OF POLYSTYRENE - VOLATILE COMPOUNDS FROM LARGE-SCALE PYROLYSIS

In order to document volatile compounds, some of which are potentially toxic, generated during large-scale commercial processes or fires, 210 mg of a polystyrene (PS) sample were degraded in a Pyrex® pyrolysis unit at 300 °C in air or nitrogen. The volatiles were desorbed with hexane from an enriched glass cold trap, following cooling in liquid nitrogen, and analysed by GC and GC/MS on a 25 m SE-54 column using splitless-mode injection. Temperature-programmed retention indices using C7C36 n-alkane standards were calculated and used to identify compounds common to decomposition in air and nitrogen. Varying proportions of chiefly phenyl-substituted saturated or unsaturated aliphatic compounds of up to 12 carbon atoms in chain length and molecular weight in the range 92-430 were found. The compounds also included a number of oxygen-containing compounds in the form of alcohols, aldehydes and ketones. Taken together, air and nitrogen decomposition produced at least 190 compounds, with at least 45 of these common to decomposition in both atmospheres. Most of the compounds occurred in small relative yields. © 1990.