Cooling rate dependence of the crystallinity at nonisothermal crystallization of polymers: A phenomenological model

The cooling rate dependence of the crystallinity of polymers is investigated via the example of different technical polypropylenes using fast scanning calorimetry (FSC) in a cooling rate range between 1 and 5000 K s −1 . In the slower cooling rate range (below 100 K s −1 ) the crystallinity increases slightly with decreasing cooling rate. Above cooling at 100 K s −1 the crystallinity decreases substantially and vanishes at the critical cooling rate. We describe this behavior using a simplified model with two components: the generic crystallinity function and the retardation function. For a mathematical description, we use empirically fitted functions that describe the cooling rate dependence of the crystallinity and the critical cooling rate.