Dynamic Covalent Polymeric Foams: En Route to a Sustainable Lightness

The broad versatility of polymer foams has driven their industrial development in commodity usages and cutting-edge technologies seeking lightweight and multifunctionality. The downside of this booming production lies in the limited end-of-life options of their waste that poses significant environmental challenges and urges the development of circular alternatives. Building on recent advances in dynamic covalent polymer networks (DCPNs), one promising route lies in the activation or the incorporation of dynamic covalent bonds (DCBs) into polymer foams. Thermally induced topological rearrangements are thus enabled by dynamic exchange reactions, unlocking new functionalities. This concept gave rise to dynamic covalent polymer foams (DCPFs), a class of materials that provide recyclability without compromising the mechanical strength and the dimensional stability traditionally required for cellular materials. In line with the United Nations Sustainable Development Goals (UN SDGs), the emergence of these dynamic networks redefines the value chain of polymeric foams. Strategies for designing DCPFs are truly numerous, all drawing inspiration from the literature on dynamic exchange chemistry. However, a clear review of the strategies, processes, materials, and new functions is still missing. This review tends to fill this gap.