Toughening PVC with Biocompatible PCL Softeners for Supreme Mechanical Properties,Morphology, Shape Memory Effects,and FFF Printability

In this article, a first of its kind blend of polyvinyl chloride (PVC) and biocompatible polycaprolactone (PCL) is introduced by melt mixing and then 3D printed successfully via Fused Filament Fabrication (FFF). Experimental tests are carried out on PCL-PVC blends to assess thermo-mechanical behaviors, morphology, fracture toughness, shape-memory effects and printability. Macro and microscopic tests reveal that PVC-PCL compounds are miscible due to high molecular compatibility and strong interaction. This causes extraordinary mechanical properties specially for PVC-10 wt% PCL. In addition to the desired tensile strength (45 MPa), this material has a completely rubbery behavior at ambient temperature, and its total elongation is more than 81%. In addition, due to the high formability of PVC-PCL at ambient temperature, it has capability of being programed via different shape-memory protocols. Programming tests show that PVC-PCL blends have an excellent shape-memory effect and result in 100% shape recovery. SEM results prove a high improvement of PVC printability with the addition of 10 wt% PCL. Toughened PVC by PCL is herein added to the materials library of FFF 3D printers and expected to revolutionize applications of PVC compounds in the field of biomedical 3D and 4D printing due to its appropriate thermo-mechanical properties, supreme printability, and excellent biocompatibility.