Premium
High‐temperature polymerization of styrene: Mechanism determination with preparative gel permeation chromatography, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and 13 C nuclear magnetic resonance
Author(s) -
Campbell J. D.,
Allaway J. A.,
Teymour F.,
Morbidelli M.
Publication year - 2004
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.20914
Subject(s) - mass spectrometry , gel permeation chromatography , desorption , matrix assisted laser desorption/ionization , polymerization , analytical chemistry (journal) , chemistry , materials science , styrene , ionization , chromatography , nuclear magnetic resonance , polymer , copolymer , ion , organic chemistry , physics , adsorption
An experimental study designed to elucidate mechanistic details regarding the thermal polymerization of styrene between 260 and 340°C is reported. The data show that back‐biting to the third or fifth carbon from the chain end, followed by β scission, is the dominant chain‐producing reaction in the molecular weight development. This conclusion is supported by the 13 C‐NMR data coupled with preparative gel permeation chromatography, which show that the predominant low‐molecular‐weight oligomers are 2,4‐diphenyl‐1‐butene and 2,4,6‐triphenyl‐1‐hexene, that is, the products of the 1:3 and 1:5 back‐biting/β‐scission reactions, respectively. The presence of head‐to‐head or head‐to‐tail branching, due to chain transfer to the polymer or back‐biting, is shown to be negligible through 13 C‐NMR analysis. Finally, the distribution of terminal unsaturations, determined by the relative rates of termination, back‐biting, and chain transfer to polymer, has been measured with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. This has shown that the back‐biting/β‐scission reaction dominates the molecular weight development in comparison with either termination or chain transfer to the polymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 890–908, 2004