Chalissery, DilipDilipChalisseryGalambos, TheodorTheodorGalambosCheerla, SupriyaSupriyaCheerlaZiervogel, FabianFabianZiervogelPretsch, ThorstenThorstenPretsch2023-09-082023-09-082023-09-07https://publica.fraunhofer.de/handle/publica/450406Shape memory polymers (SMPs) are smart materials capable of fixing a temporary shape after a thermomechanical treatment, also known as programming. When a suitable stimulus is applied, SMPs are able to almost completely recover the initial shape. Under certain conditions, phase-segregated SMPs can also undergo thermoreversible shape changes. The material behaviour is determined by the phase transitions of the switching segment, namely their melting and crystallization, and by entropy elasticity. Additive manufacturing (AM) is a promising and well-established technology platform for bringing polymers into a desired shape. Against the background of the functionalities that can be realized, three scenarios can be distinguished. 1. AM with SMPs, followed by external programming to implement e.g. one-way or two-way shape memory effects. 2. In-situ function-integrated AM to obtain SMPs with one-way shape memory effect. 3. In-situ function-integrated AM to produce SMPs with two-way shape memory effect. Although the first method allows SMPs to be obtained in a permanent shape, programming can sometimes be time-consuming, as a predefined sequence of thermomechanical steps must be strictly followed, e.g. when using a universal testing machine in combination with a temperature chamber. The other two methods, in turn allow the fabrication of objects with predetermined thermoresponsiveness. Thus, so-called four-dimensional (4D) printing makes it possible to bring thermoresponsive objects from the printing chamber into the technical application. In the presentation, examples will be provided in which fused filament fabrication is employed as AM technique to print objects from polyurethane-based SMPs according to the scenarios described above.en4D printingshape-memory polymerprogrammable materialpolyurethanefused filament fabricationthermoresponsiveadditive manufacturingpresentation