ie9b06520_si_001.pdf (294.51 kB)
Reprocessable Epoxy Resins Based on Hydroxy-Thioester and Thiol-Thioester Dual Exchanges
journal contribution
posted on 2020-03-06, 13:35 authored by Yumin Yang, Qingfei Song, Chunmei Li, Jiaojun Tan, Ying Xue, Zhengzhou Su, Guoxian Zhang, Qiuyu ZhangEpoxy
resins are widely used due to their excellent physical and
mechanical properties; however, their recycle and reprocessing remain
challenging up to now. This problem may be solved by incorporating
dynamic covalent cross-links into epoxy resins, and thus they have
the potential to increase their service lifetimes and reduce their
environmental impact. This work innovatively proposes the introducing
of thioester groups into epoxy resins. Under proper conditions, the
thioester will exchange with the hydroxyl groups of epoxy E51, which
will produce thiol and ester groups. Then, the thiol-thioester exchange
will be triggered subsequently. The proposed hydroxyl-thioester and
thiol-thioester dual exchanges endow the epoxy materials with reprocessability.
We designed model experiments to demonstrate the exchange capacity
of hydroxyls/thioesters and thiols/thioesters under mild conditions.
New epoxy resin materials have been developed based on thioester-containing
curing agents. The reprocessing of the thioester-containing epoxy
resin was very simple and efficient. After three reprocessing cycles,
the mechanical properties of the epoxy resin material were comparable
to the pristine material. In addition, the reprocessing epoxy materials
had excellent shape memory properties. This work provides new ideas
for the development of epoxy resins and opens up a new pathway for
the application of thioesters.