Thermodynamics and Stereochemistry of Diels–Alder Polymer Networks: Role of Crosslinker Flexibility and Crosslinking Density

• DOI: 10.1021/acs.macromol.1c01662
• Publication Date: 2021-11-11T16:36:11Z
• Authors: Qing Zhou; Zhen Sang; Kartik Kumar Raja...; Yelena Sliozberg; Frank Gardea; Svetlana A. Sukhi...
• Keywords: Maleimide; Reconfigurability; Polymer network; Imide; Control reconfiguration; Network covalent bonding; Furan

Dynamic covalent polymer networks crosslinked through Diels–Alder (DA) reactions are promising self-healing, 3D-printable materials that have the unique ability to reshuffle their dynamic bonds in solid state. Here, we identify main parameters control furan/maleimide-based DA network and relate them shape reconfigurability. Thermodynamics of were dominated by entropic effects, with more flexible crosslinkers leading higher bond dissociation temperatures. Furthermore, fraction endo vs exo adducts increased crosslinking density. Less thermally stable endo-attached crosslinks exploited for reconfiguration via conversion thermal annealing between Tg temperature network. Moreover, repeatable re-arrangements material thermodynamically all-exo achieved at a elevated temperature.