Recrystallization during melting

In the present work we address ourselves to two problems directly concerned with determining the physical quantities required for the different extrapolations. The first of these is concerned with the relation of the melting temperature determined by differential calorimetry to the true melting temperature. The other involves an analysis of melting-recrystallization during a DSC scan and its influence on the observed melting temperature. 

From H-NMR analysis, the crystallinity decreases and exhibits a minimum value around 60 °C, then increases as the temperature increases. These decrement and subsequent increment in crystallinity coincide with those of the reflection intensities observed for the variable-temperature WAXD profile. Heating produces maximum crystallinity at about 120 °C followed by the abmpt drops in crystallinity, which is attributed to the sample melting. These temperatures of the maximum crystallinity coincide well with the temperatures at which the lamellae appear in the TEM observations. These results indicate that the lamellar formation originates from melt recrystallization during annealing. 

Processing conditions influence the performance of plastics. For example, heating a crystalline material above its melting point, then quenching it can produce a plastic that has a far more amorphous structure. Its properties can be significantly different than if it is cooled properly (slowly) and allowed to recrystallize during processing it becomes amorphous. The effects of time are similar to those of temperature in the sense that any... 

When the date of interest refers to the crystallization of rocks or minerals from a melt and all of the above criteria are met, the interpreted age is best referred to as an igneous age. When minerals in a single rock are the products of solid-state recrystallization during metamorphism and all the above criteria are met, then the calculated date may be referred to as a metamorphic age. 

In spite of the lower melting temperature of P-iPP, its heat distortion temperature exceeds that of a-iPP [3]. This could be explained by the Pa-recrystallization during heating which generates an a-phase of higher melting temperature [1, 2]. 

There are two theories to explain the behavior of double endothermic peaks. One is the melt-recrystallization mechanism. The peak at lower temperature was from the melting of the initial crystal lamellae formed during the isothermal crystallization. When the... 

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