Strong and stiff thiourea-based polymer networks with thermadapt shape memory and on-demand recycling capabilities

Abstract

We report thiourea-based polymer networks (TPNs) synthesized via a simple, by-product-free polyaddition using aromatic diisothiocyanates, short-chain alkylenediamines, and a triamine crosslinker. The TPNs exhibit excellent mechanical performance (tensile strength up to ≈74 MPa, elastic modulus of ≈2.4 GPa) along with thermadapt shape memory behaviors. Thiourea moieties act as dual-functional motifs, forming dense hydrogen-bonding interactions while enabling dynamic covalent bond exchange at elevated temperatures. This duality allows for catalyst-free thermal reprocessing and chemical recycling without compromising mechanical integrity. These findings highlight the potential of TPNs as robust, thermally adaptive, and recyclable materials for sustainable and intelligent structural applications.