PCL-based materials exhibit distinctly different thermal properties. The first heating (Figure ) and cooling (Figure ) curves are characteristic of PCL . The glass transition temperature of the PCL-based materials tested, determined from the first heating scan, is approximately -60 °C. This explains the ductile nature of PCL at room temperature, as discussed in section 3.1. Compared to PLA, the absence of cold crystallisation and the clear endothermic melting peak observed in the temperature range of around 40-70 °C indicate a high degree of polymer crystallinity in the produced materials. Leung et al. also observed no significant effect of the HAp filler on the thermal properties determined by the DSC method, which they attributed to weak interactions between the HAp particles and the PCL matrix. A key difference between PLA and PCL is that PCL readily crystallises from the melt, as evidenced by the cooling curve (Figure ). The crystallisation and glass transition temperatures also show slight differences.