Superposition kinetic crystallization curves

Equation (3) is the most widely used in analyzing experimental curves, since its form is intuitively clear the rate of the defect accumulation is determined by the fraction of free volume of the crystal not occupied by previously created defects, without taking account of the overlap of the annihilation volumes of similar defects. Evidently it is applicable only in the initial stage of accumulation kinetics at relatively low concentrations of defects, nvo superposition approximation corresponds to the first two terms of expansion (2) in powers of nvo-... 

Two typical cases are illustrated in Fig. 2.24 the first scheme (Fig. 2.24 a) is related to high-temperature polymerization, in which newly formed polymer is molten and the processes of polymerization (part Ob of the full curve) and crystallization (part bK of the full curve) are separated in time. The second case (Fig. 2.24 b) illustrates low-temperature polymerization in this situation crystallization starts before the full process of polymerization is completed. This is typical superposition of two kinetic processes, and the shape of the curve in Fig. 2.24 b does not allow the separation of these processes without additional information and assumptions.The net heat effect is the same in... 

If the crystallization kinetics is determined by DSC, both primary nucleation and crystal growth will make a contribution, resulting in a mathematical superposition of both bell-shaped curves shown in Figure 11.6. It is useful to be able to extract from DSC data not only the conomonly obtained overall crystallization rate but also the separation of the individual contributions of the primary nucleation and the growth rate. 

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