3D and 4D Printing of Polyethylene Terephthalate Glycol–Polypropylene Blends

ABSTRACT Polypropylene is one of the most widely used industrial thermoplastics, which, despite its high consumption in various industries, especially packaging, is not used much in the emerging field of 3D printing. In this article, for the first time, PETG is used in three weight percentages of 55%, 70%, and 85% to enhance polypropylene's printability, mechanical properties, and shape memory effect. The results of the mechanical properties showed that the mechanical properties increase continuously with the increase in the amount of PETG, and the blend containing 85% has the highest tensile strength (22.6 MPa) and Young's modulus (4.93 GPa). This blend also has a better shape memory behavior, and with a high shape recovery of 90% in less than 10 s, it is a suitable, cheap, and recyclable option to be added to the 4D printing library. On the other hand, the blend containing the lowest PETG (55%) also has acceptable tensile strength (17.45 MPa) and shape recovery (80%) and excellent formability (100% elongation), which makes it ideal for applications such as actuators and flexible textiles. The results of SEM and DMTA also indicated the biphasic structure of the PETG–PP blends with good compatibility. Also, the printability of all three blends played a significant role in achieving ideal mechanical properties and shape memory effect.