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Title: Cross-linker control of vitrimer flow
Vitrimers are a class of covalent adaptable networks (CANs) that undergo topology reconfiguration via associative exchange reactions, enabling reprocessing at elevated temperatures. Here, we show that cross-linker reactivity represents an additional design parameter to tune stress relaxation rates in vitrimers. Guided by calculated activation barriers, we prepared a series of cross-linkers with varying reactivity for the conjugate addition—elimination of thiols in a PDMS vitrimer. Surprisingly, despite a wide range of stress relaxation rates, we observe that the flow activation energy of the bulk material is independent of the cross-linker structure. Superposition of storage and loss moduli from frequency sweeps can be performed for different cross-linkers, indicating the same exchange mechanism. We show that we can mix different cross-linkers in a single material in order to further modulate the stress relaxation behavior.  more » « less
Award ID(s):
1832256
PAR ID:
10143575
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
Polymer Chemistry
Volume:
11
Issue:
33
ISSN:
1759-9954
Page Range / eLocation ID:
5339 to 5345
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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