Evaluation and Characterization of Ultrathin Poly(3-hydroxybutyrate) Fibers Loaded with Tetraphenylporphyrin and Its Complexes with Fe(III) and Sn(IV)

The effect of small additions (1-5 wt.%) of tetraphenylporphyrin (TPP) and its complexes with Fe (III) and Sn (IV) on the structure and properties of ultrathin fibers based on poly(3-hydroxybutyrate) (PHB) has been studied. A comprehensive study of biopolymer compositions included X-ray diffraction (XRD), differential scanning calorimetry (DSC), spin probe electron paramagnetic resonance method (EPR), and scanning electron microscopy (SEM). It was demonstrated that the addition of these dopants to the PHB fibers modifies their morphology, crystallinity and segmental dynamics in the amorphous regions. The annealing at 140 degrees C affects crystallinity and molecular mobility in the amorphous regions of the fibers, however the observed changes exhibit multidirectional behavior, depending on the type of porphyrin and its concentration in the fiber. Fibers exposure to an aqueous medium at 70 degrees C causes a nonlinear change in the enthalpy of melting and challenging nature of a change of the molecular dynamics.

Automated summary

The effect of small additions of tetraphenylporphyrin and its complexes with Fe and Sn on ultrathin fibers based on poly(3-hydroxybutyrate) has been investigated. It was found that these dopants can modify the morphology, crystallinity, and segmental dynamics of the fibers. Annealing and exposure to an aqueous medium also have an impact on the properties of the fibers.