Investigating Mechanical and Shape Memory Properties of TPU/PCL Blends for Thermoplastic Splinting Applications


Soheil Sharghi Pilehrood†, Valiallah Saba†*, Sattar Gorgani-Firuzjaee‡


† Faculty of Paramedicine, AJA University of Medical Sciences, Tehran, Iran
‡ School of Allied Health Medicine, AJA University of Medical Sciences, Tehran, Iran

Corresponding Author Email: [email protected]

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Shape-memory polymers (SMPs) are widely used in splinting and patient immobilization applications. The possibility of personal fitting, low splint thickness, and patient comfort in such splints have rendered them practical in orthopedic applications. Generally, the manufacturing process of thermoplastic splints consists of chemical synthesis routes that are costly and time-consuming. This research seeks to investigate the feasibility of the physical blending to produce splinting sheets. The melt compounding was done using different ratios of TPU/PCL, including 0, 15, 30, 45, 60 and 100% of TPU in the blends, and the process continued to form polymer sheets. X-ray diffraction analysis was performed to identify the structure and the fraction of the crystalline phase. Tensile tests were carried out on the compounded products at room temperature, and the results revealed that the yield point of the samples varied between 11 MPa to 14MPa. Moreover, the dynamic thermal properties of the samples were examined using the DMTA test over a temperature range from 25 ̊C to 70 ̊C. Test results highlighted that only the blends containing 30,45 and 60% TPU are able to recover the permanent shape at temperatures above the transition temperature. The obtained compounds shape memory and mechanical properties were studied by performing tensile tests at variable temperatures. The shape fixing ratio of the samples with 30, 45 and 60% TPU was measured in the range of 84.5% to 97.1% and the shape recovery ratio varied between76.8% to 85.7%. PCL with 45wt% TPU can thus be an economical alternative for the applications mentioned above.