Biocompatible fibers from thermoplastic polyurethane reinforced with polylactic acid microfibers

• Blends of thermoplastic polyurethane (TPU) and polylactic acid (PLA) were prepared.
• Extrusion caused fibrillation of PLA in samples with 10–30 wt% PLA.
• PLA microfibers had diameters from 200 to 800 nm.
• Cold drawing of fibers introduced orientation of PLA microfibers.
• Composite fibers had higher tensile properties and stiffness than TPU.

Fiber-reinforced composites were prepared by extrusion of biphasic thermoplastic polyurethane/polylactic acid blends and the morphology was studied by electron microscopy. Reinforcing effect of in-situ formed PLA microfibers on polyurethane matrix was found. Polylactic acid (PLA) content was varied from 10 to 40 wt% resulting in reinforced polyurethane matrices with fibrils of 200–800 nm. Highly amorphous PLA fibrils crystallized when heated above glass transition, resulting in storage modulus increase as observed by dynamic mechanical analysis. Polyurethane (TPU) fibers reinforced with PLA microfibers had improved tensile strength and retained relatively high elongation, but elastic recovery decreased and hysteresis increased relative to the neat TPU. Orientation of fibers induced by cold drawing increased tensile strength and elastic modulus.

Figure optionsDownload as PowerPoint slide