crystallization of pure P(3HB-co-3HV) copolymers of 18and 30 mol% HV is extraordinarily slow and can take weeksto fully develop [172]. In any DSC studies of blends, not purerandom copolymers, it is important to take into account thefact that preferential crystallization of the faster crystalliz-ing phase will exclude the separate, slower crystallizingcomponents into a separate phase where, with time, thesecomponents can also slowly crystallize. Without allowingsufficient time (or the best temperature for annealing of thematerials) the DSC analysis will not be reflective of the finalpolymer crystallinity. This is also true for pure copolymersof high HV content.