Constructing segregated thermoset composite via Pickering emulsion and dynamic polythiourethanes

Constructing segregated structure is an efficient way to prepare conductive polymer composites (CPCs) with low filler content via confining fillers into the interstitial areas of polymer domains. However, segregated CPCs (s-CPCs) face two main restrictions, i.e., weak interactions between polymer matrix and fillers, and limitation of thermoplastic polymer matrices. In this work, we propose to prepare thermoset s-CPCs by hot-pressing of graphene oxide (GO)-coated dynamic polythiourethane (PTU) granules. Firstly, dynamic cross-linked PTU with good mechanical property via thiocarbamate associative exchange was designed. The dynamic nature and exchange reactions of thiocarbamate were verified in small molecule model reactions, and the thermal and mechanical properties of the reprocessing PTU were also investigated. Then, Pickering emulsion was adopted to prepare the cross-linked PTU@GO granules which were further hot-pressed to form entire PTU/GO s-CPC by the exchange of thiocarbamates. Three-dimensional (3D) conductive network was formed and the formation mechanism was explained. This research not only provides a new type of recyclable thermoset resin, but also establishes a novel method for preparing thermoset s-CPCs with excellent functional properties.