Effects of aging on the adhesive properties of poly(lactic acid) by atmospheric air plasma treatment

ABSTRACT The aim of this study was to analyze the durability of a plasma treatment on the surface of poly(lactic acid) (PLA). We used atmospheric‐plasma treatment with air to improve the wettability of PLA by evaluating the aging effect under controlled conditions of relative humidity (RH) and temperature (25% RH and 25°C). We studied the durability of the atmospheric‐plasma treatment by measuring the contact angle, calculating the surface energy, and observing changes in the resistance of the PLA–PLA adhesive bonds. These techniques allowed us to evaluate the hydrophobic recovery phenomenon that the PLA surface suffered as a consequence of the aging process. The results provide the maximum storage time of PLA treated with atmospheric plasma at which the sample retained its good adhesion properties; this time was lower than 3 days under normal atmospheric conditions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43040.