Premium
Mechanism and kinetics of polyethylene crosslinking by α,α′‐bis( tert ‐butylperoxy)‐ p ‐diisopropylbenzene
Author(s) -
Šimúnková D.,
Rado R.,
Mlejnek O.
Publication year - 1970
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1970.070140716
Subject(s) - polyethylene , decomposition , peroxide , radical , activation energy , polymer , kinetics , polymer chemistry , reaction mechanism , chemistry , octane , materials science , photochemistry , organic chemistry , catalysis , physics , quantum mechanics
The study of the mechanism of polyethylene crosslinking is realized by a kinetic analysis of the α,α‐bis( tert ‐butylperoxy)‐ p ‐diisopropylbenzene decomposition, as well as by the determination of its decomposition products and crosslink formation in the polymer. The experiments were carried out in a temperature range of 118°–148°C in both polyethylene and its low‐molecular model, n ‐octane. From the results obtained it follows that the peroxide decomposition in both hydrocarbon media is kinetically a unimolecular reaction with an activation energy of 36 ± 2 kcal/mole and with an equivalent participation of both peroxidic groups, whereby a biradical formation is improbable. Macroradicals arise by a dehydrogenization reaction in which mainly primary oxyradicals of various types take part and methyl radicals are also formed by a transformation process of the former. Both types of radicals decay exclusively in a substitution reaction with polymer chains. The whole process is terminated by macroradical recombination so leading to crosslink formation in polyethylene.