Synthetic–Natural Bionanocomposite Hydrogels on the Basis of Polyvinyl Alcohol and Egg White

ABSTRACT

A series of bionanocomposite hydrogels composed of polyvinyl alcohol, a synthetic polymer, and egg white, a natural protein containing material, were prepared by the freezing- thawing cyclic method. Na-montmorillonite nanoclay (Na-MMT), as a crosslinker and reinforcing agent, with 0, 5, 10, and 15 wt% loadings (based on the dried mass of the bionanocomposite hydrogel) was incorporated in the polyvinyl alcohol and egg white hydrogel matrix. The microstructural characteristics of the prepared bionanocomposite hydrogels were characterized by the X-ray diffractometry, transmission electron microscopy, Fourier transform infrared spectroscopy, scanning electron microscopy and gel fraction measurements. Thermal and mechanical properties of the samples were also studied using differential scanning calorimetry and dynamic mechanical-thermal analysis. The swelling and drying kinetics and mechanisms of the bionanocomposite hydrogels were also studied. The bionanocomposite hydrogels had an exfoliated Na-MMT morphology with an appropriate dispersion of nanoclay layers in the hydrogel matrix. The results showed that the Na-MMT platelets acted as crosslinkers and created a hydrogel network with a smaller pore size in the bio-nanocomposite hydrogels, compared with the clay-free hydrogel. The obtained thermal and mechanical properties confirmed the reinforcing effect of the nanoclay in the bionanocomposite hydrogels. The swelling and drying rates of the bionanocomposite hydrogels exhibited an inverse dependency on the nanoclay loading. In general, it was concluded that the prepared bionanocomposite hydrogels could be used as appropriate biomaterials in biomedical applications, especially in drug delivery, tissue engineering and wound care.

Keywords:

• bionanocomposite hydrogel
• egg white
• nanoclay
• polyvinyl alcohol

Acknowledgment

Y. Shaabani expresses her appreciation to the Iran Nanotechnology Initiative Council for an award following completion of her thesis.