Influence of ozone and UV on the structure of fibrous materials based on poly (3-hydroxybutyrate) and polylactide
Electrospinning yielded ultrafine fibers based on mixtures of biodegradable polyesters: poly- (3-hydroxybutyrate) and polylactide. Using optical microscopy, it was shown that mixed fibers, depending on the composition, have different diameters and geometries. Using the EPR and DSC methods, the structure of the crystalline and amorphous regions of the fibers was analyzed. The introduction of 10 - 70 % polyhydroxybutyrate into the polylactide matrix leads to a sharp increase in molecular mobility, but the concentration of the radical in the amorphous regions decreases sharply. With an increase in the concentration of PHB in the mixture (more than 70 %), a decrease in molecular mobility is observed. Studies of the state of the polymer matrix for the first time made it possible to interpret at the supramolecular level the effects of ozone and UV on the structural and dynamic characteristics of PHB / PLA fibers. It was shown that in mixtures the correlation time of the radical is minimal and does not depend on the ratio of polymers in the fiber and the time of exposure to ozone and UV irradiation.