Dynamic covalent chemistries have attracted much attention to create reversibly crosslinked covalent polymer networks that show improved processability compared to irreversibly crosslinked networks. In dissociative networks, the crosslink density of the polymer network decreases with increasing time and intensity of the adequate stimulus, such as heat or light, resulting in a dramatic change in the viscoelastic behaviour. In contrast, associative networks do not show a change in network connectivity. The rate at which a certain functional group can exchange bonds with existing covalent bonds changes upon the increase of the stimulus intensity. Dynamic covalent chemistries have also become very popular to create self-healing materials that are able to reform broken covalent bonds to recover their functional properties, increasing the service lifetime of structures and systems. The thermoreversible Diels-Alder cycloaddition reaction between furan and maleimide is the most widely studied reversible covalent chemistry for creating thermally reversible covalent polymer networks. Accurate knowledge of the reaction kinetics and thermodynamics and the structure-processing-property relations allow to design and optimize the functional properties in view of intended applications and to tailor the processability of the reversible polymer networks. The dynamically reversible chemistry, choice of monomers and resulting polymer network architecture determine the (thermo)mechanical properties, thermoresponsive behaviour and healing capabilities of the created reversible networks. Heating the thermally reversible polymer networks based on the Diels-Alder reaction shifts the reaction equilibrium towards the gradual breaking of the cycloadduct crosslinks, eventually leading to degelation. This reversible gel transition was employed to create filaments for the 3D printing of compliant components for a self-healing soft robotic gripper.