TY  - EJOU
AU  - Morgado, Nayara Koba de Moura 
AU  - Morgado, Guilherme Ferreira de Melo 
AU  - Anjos, Erick Gabriel Ribeiro dos 
AU  - Passador, Fabio Roberto 

TI  - Advanced Poly(Lactic Acid)/Thermoplastic Polyurethane Blend-Based Nanocomposites with Carbon Nanotubes and Graphene Nanoplatelets for Shape Memory
T2  - Journal of Polymer Materials

PY  - 2025
VL  - 42
IS  - 1
SN  - 0976-3449

AB  - The continuous improvement in patient care and recovery is driving the development of innovative materials for medical applications. Medical sutures, essential for securing implants and closing deep wounds, have evolved to incorporate smart materials capable of responding to various stimuli. This study explores the potential of thermoresponsive sutures, made from shape memory materials, that contract upon heating to bring loose stitches closer together, promoting optimal wound closure. We developed nanocomposites based on a blend of poly(lactic acid) (PLA) and thermoplastic polyurethane (TPU)—biopolymers that inherently exhibit shape memory—enhanced with carbon nanotubes (CNT) and graphene nanoplatelets (GN) to improve mechanical performance. PLA/TPU (50/50) nanocomposites were prepared with 1 and 2 wt% GN, as well as hybrid formulations combining 1 wt% CNT with 1 or 2 wt% GN, using a twin-screw extrusion process to form filaments. These filaments were characterized through differential scanning calorimetry (DSC), field emission gun scanning electron microscopy (FEG-SEM), tensile testing, and shape memory assessments. While the PLA/TPU blend is immiscible, TPU enhances the crystallinity (X<sub>c</sub>) of the PLA phase, further increased by the addition of CNT and GN. FEG-SEM images indicate CNTs primarily in the PLA phase and GN in the TPU phase. PLA/TPU with 1 or 2 wt% GN showed the highest potential for suture applications, with a high elastic modulus (~1000 MPa), significant strain at break (~10%), and effective shape recovery (~20% at 55°C for 30 min). These findings suggest that these nanocomposites can enhance suture performance with controlled shape recovery that is suitable for medical use.
KW  - Shape memory polymers; poly(lactic acid) (PLA); thermoplastic polyurethane (TPU); carbon nanotubes (CNT); graphene nanoplatelets (GN)

DO  - 10.32604/jpm.2025.059364