Shore hardness of bulk polyurethane affects the properties of nanofibrous materials differently

Abstract

The present study shows the effect of the hardness of bulk polyurethane on the properties of nanofibrous materials produced in the solution blow spinning process. This study focuses on nanofibrous materials made from medical-grade polyurethanes with different hardness values on the Shore scale, from 75A to 75D. We aimed to determine the effect of the intrinsic properties of polyurethane used to produce nanofibers on the tensile properties of the resulting nanofibrous materials and in vitro platelet adhesiveness. This study used a solution blow spinning process to produce nanofibrous materials from polyurethane solutions. It evaluates their properties using scanning electron microscopy, followed by porosity determination, tensile testing, and platelet adhesion assays. Generally, the bulk polymer's Shore hardness affects nanofibrous products' porosity and tensile properties. In the tested Shore hardness range, the most visible differences in material properties were observed for the fibers produced from the hardest (75D) and softest (75A) polyurethanes. The nanofibrous material produced using 75D polyurethane exhibited the highest porosity, up to approximately 0.87, owing to the low packing density of the stiff nanofibers. It also remained the stiffest, with the highest Young's modulus. On the other hand, the softest 75A polyurethane produced a less porous nanofibrous mat with the highest tensile strength among the tested polyurethanes. All tested nanofibrous materials retained their platelet adhesion resistance upon processing into nanofibers, with a mean platelet coverage below 1 % of the nanofibrous mat surface. The study results provide insights into the relationship between the hardness of bulk polyurethane and the properties of nanofibrous materials, which can be useful in various biomedical applications, particularly in producing tissue-engineered vascular grafts.