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 5000Ks(-1). In the slower cooling rate range (below 100Ks(-1)) the crystallinity increases slightly with decreasing cooling rate. Above cooling at 100Ks(-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. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42977.