Lauritzen-Hoffman theory experimental data

The Lauritzen-Hoffman (LH) theory has been the dominant growth theory for polymer crystallization for the last 20 years. New experimental data have led to the revision and development of the theory during recent years. The original theory of Lauritzen and Hoffman (1960) is presented here in detail. Later modifications of the theory are outlined in the subsequent text. Finally, criticisms of the LH theory including the later developed versions are mentioned and discussed. 

Most of the kinetic work has dealt with the temperature dependence of the growth rate in accordance with the kinetic theory of Lauritzen and Hoffman (see Hoffman et al. 1975). The experimental data, the linear growth rate (G) of spherulites (axialites), are obtained by hot-stage polarized light microscopy at different constant temperatures and the data are adapted to the equation ... 

In this chapter, we take a practical approach to briefly explain how to experimentally determine both spherulitic growth rates by polarized light optical Microscopy (PLOM) and overall isothermal crystallization kinetics by differential scanning calorimetry (DSC). We give examples on how to fit the data using both the Avrami theory and the Lauritzen and Hoffman theory. Both theories provide useful analytical equations that when properly handled represent valuable tools to understand crystallization kinetics and its relationship with morphology. They also have several shortcomings that are pointed out. 

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