Poly(Ethylene-Co-Vinyl Acetate)-Poly(Lactic Acid)-Poly(Styrene-Co-Methyl Methacrylate) Blends: Study of Mechanical Properties Under Hydrolytic Degradation and Cytotoxic Evaluation

The present research investigates the hydrolytic degradation of ternary blends composed of poly(ethylene- co-vinylacetate) (EVA), poly(lactic acid) ( PLA), and poly(styrene-co-methyl methacrylate)(poly(S-co-MMA) (SMMA) (EPS) blends at a temperature of 37 degrees C and pH 7.4, monitoring the changes in phosphate buffer solution for 6 months. In addition, the mechanical behavior and morphology of the blends were evaluated from the comparison with the degraded blends against probes non-hydrolytically degraded. Likewise, the hemolytic properties and the cytotoxicity of the blends were estimated to determine their safety if used in medical devices. Ternary blends with higher stiff-elongated properties were composed of 30 wt% EVA-69 wt% PLA and 1 wt% SMMA and prepared by varying the mixing time of each component. EPS samples presented less hydrolytic degradation than PLA. Blending PLA with EVA and SMMA resulted in significant mechanical stability throughout the degradation time. Biocompatibility tests reported that the interaction of EVA/PLA/SMMA films with mesenchymal stem cells showed no evidence of damage in the metabolism of the cells; thus, the films were not dangerous. Furthermore, all tested samples reported values below 5% of hemolysis; hence are classified as non and slightly hemolytic according to ASTM F756. Therefore, polymer EPS blends have potential applications in medical devices.