Chemical control of the viscoelastic properties of vinylogous urethane vitrimers.
Vinylogous urethane based vitrimers are polymer networks that have the intrinsic property to undergo network rearrangements, stress relaxation and viscoelastic flow, mediated by rapid addition/elimination reactions of free chain end amines. Here we show that the covalent exchange kinetics significantly can be influenced by combination with various simple additives. As anticipated, the exchange reactions on network level can be further accelerated using either Brønsted or Lewis acid additives. Remarkably, however, a strong inhibitory effect is observed when a base is added to the polymer matrix. These effects have been mechanistically rationalized, guided by low-molecular weight kinetic model experiments. Thus, vitrimer elastomer materials can be rationally designed to display a wide range of viscoelastic properties.
Department of Organic and Macromolecular Chemistry, Polymer Chemistry Research Group and Laboratory for Organic Synthesis, Ghent University, Krijgslaan 281 S4-bis, Ghent B-9000, Belgium.
Wim
W
Denissen
Department of Organic and Macromolecular Chemistry, Polymer Chemistry Research Group and Laboratory for Organic Synthesis, Ghent University, Krijgslaan 281 S4-bis, Ghent B-9000, Belgium.
Martijn
M
Droesbeke
Matière Molle et Chimie, UMR 7167 CNRS-ESPCI, ESPCI ParisTech, 10 rue Vauquelin, Paris 75005, France.
Renaud
R
Nicolaÿ
Matière Molle et Chimie, UMR 7167 CNRS-ESPCI, ESPCI ParisTech, 10 rue Vauquelin, Paris 75005, France.
Ludwik
L
Leibler
Department of Organic and Macromolecular Chemistry, Polymer Chemistry Research Group and Laboratory for Organic Synthesis, Ghent University, Krijgslaan 281 S4-bis, Ghent B-9000, Belgium.
Johan M
JM
Winne
Department of Organic and Macromolecular Chemistry, Polymer Chemistry Research Group and Laboratory for Organic Synthesis, Ghent University, Krijgslaan 281 S4-bis, Ghent B-9000, Belgium.
Filip E
0000-0001-7727-4155
FE
Du Prez