First and second heating traces for neat PLLA and 2 wt.% BC (modified and unmodified) – filled PLLA are shown in Fig. 3, with key data (Tg, Tm, Tc and percentage crystallinity, vc) summarized in Table 3. There is no significant difference between the samples in terms of Tg and Tm. However, the onset crystallisation temperature on second heating is clearly reduced in the presence of BC. This is due to BC/CNC acting as nucleation sites for crystal growth, as previously reported for monolithic samples