Tg results showed the addition of D43B to PLA did not produce significant changes in the polymer structure, as reported by other authors (Lewitus, McCarthy, Ophir, & Kenig, 2006). The effect of thymol on PLA was much more important; thymol caused a decrease of more than 10 C in Tg values, regardless of the presence of D43B. Similar behaviour was reported in PLA formulations with other antioxidants (Byun et al., 2010; Hwang et al., 2012). This could be explained by the plasticizing effect caused by thymol