Physically-Crosslinked, Polyvinyl Alcohol-Laponite NanocompositeXerogels: Preparation and Physicomechanical Characteriztions

Compared to chemically crosslinked ones, physically crosslinked xerogels are preferred for biomedical applicationswhere a high level of purity and known degradation profile under physiological conditions are highly demanded.The rare polyvinyl alcohol (PVA) capability to form physically crosslinked hydrogels after repeated freezingthawing(F-T) cycles along with the presence of an inorganic bioactive filler, i.e. Laponite® (LAP) makes such ananocomposite an interesting composition benefiting from tunable biological activity and physicomechanicalproperties needed for biological applications. To this end, LAP (۱-۵ wt%) was dispersed in aqueous PVA solutions(۱۱ %wt/vol) then F–T cycles (۳-۷) were repeated for solvent casted films (wet thickness = ۵ mm) by freezing at -۵C for ۰۱ h and thawing at ۰۵C for ۴ h. Films were dried at room temperature to obtain nanocomposite xerogels.The films were characterized by field emission scanning electron microscopy (FE-SEM), polarized opticalmicroscopy (POM), tensile test, Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD).Morphological examinations revealed homogenous dispersion of LAP particles in the polymer matrix with noaggregation. POM micrographs supported the crystalline structure of the transparent films exhibiting a dendritic,spherulite morphology.

کلیدواژه ها:

Polymers in Medicine ، Poly(vinyl alcohol) ، Laponite ، Xerogel ، Freezing-Thawing