As shown in Fig. 4, the behaviour of aged samples was similar to that of PC samples without any ageing process, i.e., the degradation process took place in an unique step, remaining a carbonaceous rest of about 20–25 wt% at the end of the process at 900 K. The Ti values in Table 4 reveal that the thermal stability decreased as the residence time in the QUV chamber increased, as a consequence of the degradation caused by the UV radiation on the material. More- over, as it has been observed already for the molecular weight, a sharp decrease in Ti took place in the first residence periods in the QUV chamber. However, for the samples reprocessed five times, the ageing process did not produce any significant variation in the Ti value (Table 5) after 600 h of residence in the QUV chamber. This behaviour could be due to the fact that the material was already suf- ficiently degraded in the reprocessing process and, therefore, the effect of the UV radiation did not have a significant repercussion in the sample.