Table 3 gives the induction time tind resulting from the Foubert fit
for the different blends at different crystallization temperatures. The
induction time is the time necessary to start the formation of β′ crystals,
either via polymorphic transition of α crystals in case of a twostep
crystallization, or directly from the melt in case of a one-step
crystallization. For PO, it was clear that the formation of β′ crystals directly
from the melt (25 and 28 °C) occurred later than when a polymorphic
transition took place (15, 18 and 20 °C). Also the 1% MP
blend showed a late β′ crystallization from the melt at 28 °C. At
25 °C, only a limited amount of α crystals was formed in this blend.
Most β′ crystals thus crystallized directly from the melt, as a result
of which tind in this case was high too. When a higher concentration
of MP was present (2, 4 and 8%), there was also only a little or no α
crystal formation at higher temperatures (25 and 28 °C). However,
the induction times were significantly lower. This could be attributed