Barner-Kowollik, Christopher

D'hooge, Dagmar

De Keer, Lies

Gegenhuber, Thomas

Goldmann, Anja

Reyniers, Marie-Françoise

Van Steenberge, Paul

Ghent University Academic Bibliography

TEMP076A KINETIC UNDERSTANDIG OF THE COMBINATION OFLIGHT-DRIVEN STEP-GROWTH AND RAFT POLYMERIZATIONLies De Keer (1), Thomas Gegenhuber (2), Paul H.M. Van Steenberge (1), Anja S. Goldmann (2),Marie-Françoise Reyniers (1), Christopher Barner-Kowollik (2,3), Dagmar R. D’hooge (1,4)1) Department of Materials, Textiles and Chemical Engineering, Laboratory for Chemical Technology, Ghent University,Technologiepark 914, B-9052 Zwijnaarde (Ghent), Belgium2) Preparative Macromolecular Chemistry, Institute for Technical Chemistry and Polymer Chemistry, Karlsruhe Institute ofTechnology (KIT), Engesserstraβe 18, 76128 Karlsrube, Germany3) School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), 2 George Street,Brisbane, QLD 4000, Australia4) Department of Materials, Textiles and Chemical Engineering, Centre for Textile Science and Engineering, GhentUniversity, Technologiepark 907, B-9052 Zwijnaarde (Ghent), BelgiumOver the last decade, the development of new synthesis strategies in polymer science has expanded with the aimto increase efficiency, complexity and precision control. Combining light-induced chemistry via a step-growthmechanism and reversible deactivation radical polymerization (RDRP) is one promising approach. Step-growthpolymerization can however suffer a lack of control since all functional groups can in principle react in anuncontrolled manner. Furthermore, the success of a step-growth polymerization is strongly dependent on thestoichiometry of the functional groups. Therefore, step-growth polymerization has been rarely explored inpolymer design.In this work, a unique combination of light-induced step-growth polymerization and RDRP is presented, aimingat microstructural control of the polymer product. To accomplish the light-induced polymerization Diels-Alderchemistry is used, i.e. ortho-methyl benzaldehydes (AA) are combined with electron deficient enes such asfumarates (BB) bearing a trithiocarbonate group. The reactivity of the benzaldehydes is based on thelight-triggered isomerization of an o-methyl-substituted aromatic aldehyde into an o-quinodimethane speciescarrying a highly reactive diene functionality that undergoes a Diels-Alder reaction with a fumarate group [1].Since a bisfumarate molecule is selected with a trithiocarbonate group, the step-growth polymerization generatesmacro-RAFT species enabling a subsequent chain extension via RAFT polymerization (monomer: styrene; C)within the polymer chains.The structure of the polymer product is analyzed in detail via size exclusion chromatography (SEC; see figure:left), nuclear resonance spectroscopy (NMR) and electrospray ionization mass spectroscopy (ESI-MS),evidencing the different polymerization mechanisms. Subsequently, stochastic modeling tools are applied toallow for a detailed kinetic analysis, allowing for the first time the mapping of the evolution of the number ofRAFT groups and styrene insertions per chain length (see figure: right). RAFT-specific parameters aredetermined based on an extensive set of experimental polymerization data on chain extension and a complexreaction scheme consisting of more than 200 reactions. Good agreement between experimental and simulateddata is obtained. The modeling results are useful in order to achieve in-depth knowledge of the chain extensionpossibilities. References1) Gruendling, T.; Oehlenschlaeger, K. K.; Frick, E.; Glassner, M.; Schmid, C.; Barner-Kowollik, C. Macromol.Rapid Commun. 2011, 32, 807−812.

A kinetic understanding of the combination of light-driven step-growth and RAFT polymerization

https://biblio.ugent.be/publication/8537902/file/8537903

A kinetic understanding of the combination of light-driven step-growth and RAFT polymerization

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