By differential scanning calorimetry, the thermal property has
been investigated to further study the effect of NR on the hydrolysis
of PLA. Fig. 6 shows the two heating DSC curves of each sample. The
first heating is presented in the state of the specimens before or just
after hydrolysis. For the not hydrolyzed PLA, the cold crystalline is
very obvious. By prolong the hydrolysis, the cold crystalline almost
disappeared, but a strong single peak of melting endotherm is also
displayed in the curves.