Measurements of the contact angle can provide information regarding the degree of hydrophobicity/hydrophilicity of polymer surfaces (Suresh et al., 2011). The contact angle between liquids (such as water in this work) and solid surfaces is based on the thermodynamic equilibrium between liquid, solid and gas phases. The Young's equation that defines the contact angle is derived from the interfacial energies between the involved phases. Table 4 reports the measured values of the contact angle (using water drops) for LDPE and LDPE/TPS blends and for these materials extruded 5 times and 10 times. The average values obtained exhibited a standard deviation of approximately 1°. The average measured values are found to be very similar for all of the samples, indicating minor changes in the physicochemical characteristics of surfaces with introduction of a new component (starch) or by application of several cycles of extrusion. This last result (contact angle not changing profoundly due to multiple cycles of extrusion) is another indication that no extensive degradation of the polymers was observed during reprocessing. The fact that the introduction of starch phases (typically hydrophilic) did not change the wettability of LDPE can be due to the formation of an LDPE-rich surface during molding. Because LDPE has lower viscosities than LDPE/TPS, it was probably able to flow around the starch-rich phases to encapsulate them, thus avoiding exposure of the starch on the surface of the samples.