Chen and Hwang [230] have shown that crystallinityobtained by Hf/Hf 100%can be called the ‘equivalentweight crystallinity’, signifying “the amount of perfectcrystals that can be melted by the measured enthalpy ofmelting. The equivalent weight crystallinity does not onlydepend on the amount of the crystals, but also on the per-fection of the crystals: a crystal with higher perfection haslarger equivalent weight” [230]. Samples of P(3HB-co-3HV)crystals (of 17 and 30 mol% 3HV) grown isothermally fromsolution have been shown to be very small and irregular[172]. The fold surface also became more irregular withan increase in HV content, which was attributed to inho-mogeneous distribution of HV units in the crystalline andamorphous phases. It is also known that lamellar thick-ening with increased melting temperatures and spherulitesize has been observed when PHA copolymers are crystal-lized at higher temperatures [162,195,231].