Influence of Programming and Recovery Parameters on Compressive Behaviors of 4D-Printed Biocompatible Polyvinyl Chloride or Vinyl-Poly(-Caprolactone) Blends

In this article, a new class of biocompatible shape-memory polymers (SMPs) through blending pcolyvinyl chloride or vinyl (PVC) and poly(epsilon-caprolactone) (PCL) is introduced. The compressive shape-memory behaviors of 4D-printed SMP PVC with 5 and 10 wt% of PCL are studied in detail. In this respect, a set of experiments are carried out to understand thermomechanical responses of PVC-PCL blends under various shape-memory parameters like programming temperature, load-holding time, applied strain, and recovery temperature. Dynamic mechanical thermal analysis and scanning electron microscope imaging are also performed to provide thermal and morphological analyses. It is found that by raising the recovery temperature from 45 to 65 degrees C, the shape recovery ratio increases from 5.63 to 7.92 MPa when the PVC-PCL10 is programmed via the hot-programming (HP) protocol. The highest level of shape fixity (100%) and the best performance of stress relaxation are achieved for HP sample, while the highest shape recovery ratio (100%) is obtained for cold programming. By applying the load-holding time, the amount of shape fixity can reach from 88.14% to 100%. Results of this research are expected to provide an insightful understanding of the shape-memory behaviors of PVC-PCL and be instrumental for 4D printing and programming of shape-adaptive structures like shape-memory intervertebral cages as spinal support devices. This work introduces a new class of biocompatible shape-memory polymers by blending polyvinyl chloride or vinyl and PCL. Thermomechanical and morphological analyses reveal their excellent 4D printability and performance in terms of programmability, compressive shape recovery, shape fixity, working temperature, and stress relaxation. This 4D printing will be instrumental for many applications like fabricating customized shape-memory intervertebral cages as spinal support devices.image (c) 2024 WILEY-VCH GmbH