All the results obtained in this work indicate that C15 causes greater degradation than CBPAS and CPEIA. In order to explain this result, and taking into account the key role of the hydrolysis in the degradation of PC, we firstly must consider the water content of the three clays. This water content can be compared using Fig. 2, which shows the weight losses at low temperatures (between 50 and 150 °C) of the three clays. Fig. 2 shows that C15 is the clay with smaller weight loss at low temperatures, so we can consider that the content of free water is lower in C15 than in the other clays. In this case, the water content of the clays does not appear to play a main role in the degradation of PC