The effect of chitosan form on the shape memory properties of polyurethane based composites

The continuous progress in the medicine and biotechnology demands development of novel biomaterials with multiple functions. This multifunctionality may be accomplished through combining synthetic polymers with shape memory properties and natural polymers. Shape memory composites consisting of poly(caprolactone-urethane) and chitosan (PU-2/3 PCL CH) were synthesized and evaluated in terms of structure–function correlation. Chitosan was incorporated in a form of microspheres (CH-Mic) or as the macromolecule unit (CH-m) of PCL-based polyurethane matrix (PU-2/3 PCL). The effect of chitosan on shape memory properties and transition temperature was evaluated. The PU-2/3 PCL CH-m composite demonstrated a lower transition temperature (Ttrans) of the shape recovery in comparison to neat PU-2/3 PCL matrix and PU-2/3 PCL CH-Mic composites. The composites with CH-m exhibited shape recovery immediately after reaching Ttrans whereas neat polymers and composites consisting of CH-Mic required five minutes pre-heating time before initialization of the shape recovery process.