Open AccessRoom-Temperature Self-Healable and Mechanically Robust Thermoset Polymers for Healing Delamination and Recycling Carbon Fibers
Author(s) -
Xiaming Feng,
Guoqiang Li
Publication year - 2021
Publication title -
acs applied materials and interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.535
H-Index - 228
eISSN - 1944-8252
pISSN - 1944-8244
DOI - 10.1021/acsami.1c16105
Subject(s) - materials science , thermosetting polymer , self healing material , polymer , toughness , self healing , composite material , ultimate tensile strength , epoxy , polyetherimide , monomer , medicine , alternative medicine , pathology
The advocacy of carbon neutrality and circular economy encourages people to pursue self-healing and recycling of glassy thermoset polymers in a more realistic and energy-saving manner, the best being intrinsic healing under room temperature. However, the high mechanical robustness and healing ability are mutually exclusive because of their completely opposite requirements for the mobility of the polymer networks. Here, we report a dual-cross-linked network by slightly coupling the low-molecular-weight branched polyethylenimine with an ester-containing epoxy monomer in a nonstoichiometric proportion. The highly mobile and dense noncovalent hydrogen bonds at the chain branches and ends can not only complement the mechanical robustness (tensile strength of 61.6 MPa, elastic modulus of 1.6 GPa, and toughness of 19.2 MJ/m 3 ) but also endow the glassy thermoset polymer ( T g > 40 °C) with intrinsic self-healing ability (healing efficiency > 84%) at 20 °C. Moreover, the resultant covalent adaptive network makes the thermoset polymer stable to high temperatures and solvents, yet it is readily dissolved in ethylene glycol through internal catalyzed transesterification. The application to room temperature delamination healing and carbon fiber recycling was demonstrated as a proof-of-concept.