Synthesis, Characterization, and Electrospinning of Calcium-Containing Polyurethane Urea

Abstract

Calcium‐containing segmented polyurethane urea was synthesized using a calcium salt of p‐aminobenzoic acid, polytetramethylene glycol, and 4,4′‐methylene bis(cyclohexyl isocyanate) and thereafter fabricated into three‐dimensional scaffolds for the use in biomedical applications. Biocompatibility evaluation of the polymer showed that this newly developed metal‐containing polyurethane urea demonstrated good cytocompatibility and hemocompatibility. The fabricating ability of the metal‐containing polymer was studied by the electrospinning process. The effect of various parameters such as polymer concentration, applied voltage, and flow rate on the electrospinning process, morphology, and diameter of the resultant fibers was investigated. The findings indicate that increasing the concentration and flow rate of the solution increases the fiber diameter. It was also demonstrated that increasing the applied voltage decreases the fiber diameter. Mechanical property evaluation of the scaffolds showed that the strength of the scaffold depends on both the diameter and morphology of the fibers. As the fiber diameter increases from 1.6 to 3.02 μm, the tensile strength enhanced from 3 to 7 MPa.

Electrospun Poly(carbonate-urea-urethane)s Nonwovens with Shape-Memory Properties as a Potential Biomaterial

“… 75 However, some reports claimed that the nanofibers’ tensile strength increased with the fiber diameter increase. 76 − 78 This behavior was observed for a polyurethane-based electrospun fiber scaffold, which has a chemical nature similar to our PCUUs. Han et al concluded that the lower tensile strength in the case of small-diameter fibers was caused by weaker junctions of interconnected fibers.…”

“…Theoretically, the orientation within fibers on the molecular level increases with decreasing fiber diameter, resulting in a higher mechanical strength. , Therefore, it is expected that with decreasing fiber diameter, the tensile strength of the electrospun fiber increases . However, some reports claimed that the nanofibers’ tensile strength increased with the fiber diameter increase. − This behavior was observed for a polyurethane-based electrospun fiber scaffold, which has a chemical nature similar to our PCUUs. Han et al concluded that the lower tensile strength in the case of small-diameter fibers was caused by weaker junctions of interconnected fibers .…”

Mechanical Properties of Electrospun Fibers—A Critical Review

“…Another factor that can influence the mechanical properties is the applied electrical voltage [38c,68a,70] . An increase in the electrospinning voltage can alter the shape of the initial droplet, consequently changing the fiber shape from a typical cylindrical to a beaded or string‐of‐pearl structure.…”

“…However, some reports claimed that the tensile strength of the nanofibers increased with increase of the fiber diameter. [ 67,68 ] Both Nair and Parameswaran and Han et al found the trend of increase in the tensile strength with increasing fiber diameter for a polyurethane‐based electrospun fiber scaffold [68a,b] . They inferred that the lower tensile strength for small‐diameter fibers was due to the weaker junctions of interconnected fibers.…”