Recyclable, reconfigurable, thermadapt shape memory polythiourethane networks with multiple dynamic bonds for recycling of carbon fiber-reinforced composites

Thermoset polyurethane is an important polymer material due to high strength and adjustable performance. However, the thermoset polyurethane only based on dynamic urethane bond shows poor reprocessing performance. To improve the reprocessability and recyclability, multiple dynamic covalent bonds (ester, urethane, and thiourethane bonds) were introduced into molecular chains to develop a thermoset shape memory polythiourethane (PCTU) with high transparency, excellent mechanical properties, solid state plasticity, reprocessability, and recyclability. The PCTU samples show good mechanical properties and have the highest reprocessing efficiencies with ησ of 144.4% and ηε of 160.1%. Moreover, the samples can realize complex 3D shapes via the combination of solid-state plasticity and shape memory property. Notably, for the prepared PCTU/CFs composites, carbon fibers (CFs) can be easily recycled under mild conditions and can be reused in other polymer composites. Thus, this work provides a new way for developing recyclable, reconfigurable, and thermadapt shape memory polythiourethane fiber composites.