Fabrication and experimental characterizations of smart material filaments (SMFs) for possible future 4D-printing applications

The absence of established quality benchmark experimental characterizations for validating SMFs performance represents a substantial hurdle in the possible development of 4D-printing applications via FDM-mediated 3DP techniques. To address this concern, we successfully fabricated seven different batches of SMFs (B 1 to B 7 ) by altering the PU:S100 ratios through hot-melt extrusion (HME) process at a fixed extrusion temperature (170 °C) and extrusion speed (40 rpm) and characterized them with a thorough qualitative and quantitative strategy for assessing the fabricated SMFs, not only for effective FDM-mediated 3DP processes but also for possible future 4D-printing applications as well. Detailed experimental characterization analyses of the seven different batches of SMFs (B 1 to B 7 ) were systematically performed using DSC, DMA, TGA, 3PBT, tensile test, FTIR, Raman Mapping, XRD, and FE-SEM followed by FDM-mediated 3DP assessment. Through this series of experimental characterizations, it was found that B 4 showed comparatively better solid-state physico-technological properties with stable thermal profiles up to 300 ºC temperature, high mechanical strength, and non-brittleness features. Thus SMFs (B 4) is suitable for further FDM-mediated 3DP process for possible future 4D-printing applications to deliver the drug. Graphical abstract