Abstract
A series of acetylsalicylic acid-poly(vinylalcohol-
co
-ethylene) blends (AcSa/PVAE) of different compositions were prepared by dissolution and solvent evaporation then characterized by the solubility test, differential scanning calorimetry (DSC), X-ray diffractometer (XRD) and by scanning electron microscopy (SEM) analyses. The results revealed that AcSa was perfectly soluble in PVAE up to a certain composition. A non-isothermal study of the crystallization kinetic of AcSa/PVAE materials was carried out by the DSC method. It was observed that the Ozawa equation perfectly describes the primary process of non-isothermal crystallization of this material. There is a strong dependence of AcSa/PVAE composition on the crystallization parameters. In general, at any cooling rate the variation in
t
1/2
of crystallization
vs.
the AcSa/PVAE composition passed by a minimum then a maximum of 7 and 5 wt% of AcSa, respectively. The crystallization activation energy (
E
a
) calculated from the Kissinger model reached a maximum when the concentration of AcSa in the AcSa/PVAE system was 8.5 wt%. The release dynamic of AcSa from AcSa/PVAE material was tested at body temperature during 92 h. On the light of the data obtained, it was found that at pH 5 and 7, AcSa/PVAE 15 presented the best performance because this material was capable of releasing more than 50 wt% of the AcSa amount uniformly (1.30±0.8 wt%/h) during 38–39 h.