Tuning of renewable sponge-like polyurethane physical-chemical and morphological properties using the pullulan as a reactive filler

This study aimed to evaluate the effect of pullulan (Pull) on a renewable polyurethane sponge-like scaffold synthesized from the Pull mixture with the castor oil-based polyol and the prepolymer using the situ foaming method. The Pull contents on the sponge-like are 5, 10, and 20 wt.%. The samples were evaluated by optical microscopy (OM), scanning electron microscopy (SEM), density, Fourier transform infrared spectroscopy (FTIR), contact angle, Thermogravimetry, X-ray diffraction analysis (XRD), and compression strength test, respectively. FTIR results indicated that Pull was hydrogen-bonded to PU foam chains and increased the sponge-like scaffolds density, inducing a decrease in average cell size compared to the pristine PU, confirming that they act as nucleating agents. The Pull addition improved PU foams' hydrophobicity and mechanical properties and caused a thermal stability median between Pull and pristine PU. Thus, all renewable sponge-like scaffolds were hydrophobics and presented appropriate mechanical behavior, exhibiting better physicochemical properties, and appearing as promising candidates for biomedical applications.