Stabilisation of LDPE cross-linked in the presence of peroxides III. Mass spectrometric study of chemical changes taking place in the n-octadecane–dicumyl peroxide–Irganox 1081 system

Abstract

An attempt was made to identify the products of the reaction between dicumyl peroxide and Irganox 1081, carried out in n-octadecane (saturated hydrocarbon), in conditions of fast decomposition of the peroxide (180°C, 5 min). Mass spectrometry (MS) was employed to find m/z values of molecular and fragment ions in analyses of the components ( n-octadecane, dicumyl peroxide, Irganox 1081) and of the following systems: n-octadecane–dicumyl peroxide, n-octadecane–Irganox 1081 and n-octadecane–dicumyl peroxide–Irganox 1081, after holding them at a temperature of 180°C for 5 min. The tendency of sulphur in Irganox 1081 to oxidise, specifically in the presence of dicumyl peroxide, was confirmed. Hypothetical formulae of Irganox 1081 derivatives, resulting from the reaction between Irganox and the peroxide, were proposed.