Evaluation of Shape Memory in Poly(lactic acid)/ thermoplastic Polyurethane Filaments with Carbon Nanotubes and Graphene Nanoplatelets

Abstract Medical sutures are used in tissues to join the edges of wounds to help a healing process or stabilize implants. The patient's feverish state can lead to premature suture rupture, due to the increase in body temperature and the swelling due to an inflammatory process in the wound. Some materials can adapt to body temperature and may prevent this disruption, being polymers with shape memory an alternative for this application, such as poly(lactic acid) (PLA) and thermoplastic polyurethane (TPU). The addition of carbon nanotubes (MWCNT) and graphene nanoplatelets (GNP) can induce antimicrobial activity since the wound and/or suture tend to facilitate the proliferation of microorganisms, which can harm or avoid the healing process. In this work, PLA/TPU (60/40) and nanocomposites with 2 wt% of GNP and hybrids with 1 wt% of MWCNT and 1 wt% of GNP are prepared using the extrusion process. The samples are characterized by tensile test, thermogravimetric analysis (TGA), differential scanning calorimetry, field emission scanning electron microscopy, shape memory, and antimicrobial activity. The polymer blend and nanocomposites present an average shape recovery (≈6.5% in length) and the addition of nanofillers induced antimicrobial activity, being these materials promising for application in antimicrobial sutures with shape memory.