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Complications in the 355 nm Pulsed‐Laser Polymerization of N ‐Vinylcarbazole
Author(s) -
Yin Ming,
BarnerKowollik Christopher,
Heuts Johan P. A.,
Davis Thomas P.
Publication year - 2001
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/1521-3927(20010901)22:13<1035::aid-marc1035>3.0.co;2-y
Subject(s) - polymerization , cationic polymerization , photopolymer , radical , photochemistry , arrhenius equation , monomer , radical polymerization , polymer , kinetics , laser , size exclusion chromatography , chemistry , polymer chemistry , materials science , activation energy , organic chemistry , optics , physics , quantum mechanics , enzyme
The propagation kinetics of N ‐vinylcarbazole (NVC) were carefully investigated via the IUPAC‐recommended pulsed‐laser polymerization/size‐exclusion chromatography technique (PLP‐SEC) in the temperature range between –20 and 20°C using 355 nm pulsed irradiation and the photo initiator 2,2‐dimethoxy‐2‐phenylacetophenone (DMPA) as a source of primary radicals. Using this experimental approach, propagation rate coefficients, k p , were not accessible for temperatures exceeding 20°C. There is strong evidence that the monomer itself is excited by pulsed‐laser light of 355 nm, thus contributing to the polymerization process via the formation of free radicals. In addition, UV light‐induced cationic polymerization processes can not be ignored as a possible side reaction. NVC polymer also absorbs strongly at 355 nm and we speculate that this may lead to bond scission and branch network formation in the PLP process. Laser‐controlled molecular weight distributions are only obtained for reaction temperatures below 20°C. The apparent Arrhenius parameters, E A and A , are 22.8 kJ·mol –1 and 3.6×10 7 L·mol –1 ·s –1 , respectively. These results are divergent from recent literature data.