Nonisothermal cold crystallization

Nonisothermal Cold Crystallization. As mentioned before, the term cold crystallization means crystallization of a polymer from the amorphous state when it is heated from the glassy state. Rrst, the molten polymer has to be quenched (i.e., cooled at an extremely high rate) in order to freeze it to an amorphous glass before crystallization can take place. Some (not all) polymers can be easily quenched to an amorphous state. A typical example is... 

Figure 2.43. A full DSC curve of quenched (amorphous) poly(ethylene terephthalate) recorded at a heating rate of 10°C/min the glass transition (at 80°C) is followed by cold crystallization and melting of crystals formed in nonisothermal cold crystallization. The baseline during the transition was drawn to show that the crystallization process lasts to the beginning of melting. Endotherm is down. (Menczel, tmpnbhshed results.)...

The graphene nanosheets impede the movements of PCL chain and inctease the system viscosity, resulting in an evident increase of crystallization activation eneigy. The nonisothermal cold ciystallization behavior of PLLA was enhanced by the presence and amount of graphene oxide. ... 

The isothermal and nonisothermal crystallization process of the most used polyolefins is discussed in this review. Major attention is directed to crystallization from the melt some examples of crystallization from solution and cold state are also reported. The description of isothermal crystallization of polyolefins constitutes the first part of this review. In the second part the nonisothermal crystallization process is treated. 

Cai, J., Han, Y. Morphology, structure, and kinetic analysis of nonisothermal cold- and melt-crystallization of syndiotactic polystyrene. J. Appl. Polym. Sci, 103,1311-1324 (2007). 

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