Morphology, mechanical properties, and shape memory effects of poly(lactic acid)/ thermoplastic polyurethane blend scaffolds prepared by thermally induced phase separation

Abstract

Novel blended scaffolds combining biobased polylactic acid (PLA) and thermoplastic polyurethane (TPU) were fabricated by thermally induced phase separation (TIPS) using two different solvents. Pure PLA and TPU polymer scaffolds using 1,4-dioxane as the sole solvent exhibited typical ladder-like structures, while blended PLA/TPU scaffolds using the same solvent showed a more uniform microstructure. When de-ionized water was added to the solution as a non-solvent, scaffolds with the mixed solvent showed more open cells and greater interconnectivity. In compression tests, it was found that specimens, including pure PLA, TPU, and blended scaffolds with the mixed solvent, showed a higher compressive modulus than their counterparts that used dioxane as the single solvent. Dynamic mechanical analysis (DMA) was employed to characterize the shape memory properties of the scaffolds. DMA indicated that the shape fixing ratio was highest in the PLA scaffolds, while the shape recovery ratio of the TPU scaffolds was the greatest among the specimens. More interestingly, when the mixed solvent was used, the shape memory property of the blended scaffolds displayed a similar deformation curve to the TPU scaffold. This was due to the presence of the TPU phase and similarity in structure between PLA/TPU and TPU scaffolds when mixed solvent was used. In the degradation test, the blended scaffolds showed a balanced degradation behavior in-between the more easily degraded PLA and the more stable TPU in the phosphate-buffered saline (PBS), and the addition of water to the systems accelerated the degradation process of the specimens. Cell culture results showed that all of the scaffolds had good biocompatibility.

Use of maleic anhydride compatibilization to improve toughness and other properties of polylactide blended with thermoplastic elastomers

“…Distinctive IR bands of TPU in the literature were OC―N―H amide band (in the urethane) at 1220, 1530 cm −1 , ―NH amine band (in the urethane) at 1528–1504 cm −1 , ―CC in aromatic rings at 1475–1600 cm −1 , and ―NCO isocyanate group at around 2340 cm −1 . The IR spectrum of PLA/TPU blend in Fig.…”

A Versatile Technique to Produce Porous Polymeric Scaffolds: The Thermally Induced Phase Separation (TIPS) Method

“…Lots of polymers have been used, among which it is worth to mention polylactic acid [18], polyurethane [19], polycaprolacton [20], etc. the metastable region, where a (quite slow) mechanism of nucleation and growth takes place, leading to (relatively) large pores.…”

TPU/PLA blend foams: Enhanced foamability, structural stability, and implications for shape memory foams

“…More recently, biodegradability of the blend has also been reported . To date, a few studies were reported on the TPU/PLA blend foams with focus on preparation of porous scaffold and shape memory foam …”