Isotactic polypropylene isothermal spherulitic crystallization

Presence of TCL changes the properties of crystalline matrix. Transcrystallization of isotactic polypropylene in the presence of different fibers has been thoroughly analyzed. Gray as the first one provided detailed description of isotactic polypropylene behavior in the presence of wood fibers using polarized light microscopy. He observed that when melted polymer is cooled down, it crystallizes in spherulite forms in nonisothermal and isothermal conditions, creating additionally a TCL. 

Pawlak A and Piorkowska E (1999) Effect of negative pressure on melting behavior of spherulites in thin films of several crystalline polymers, J Appl Polym Sd 74 1380-1385. Nowacki R, Kolasiuska J and Piorkowska E (2001) Cavitation during isothermal crystallization of isotactic polypropylene, J Appl Polym Sci 79 2439-2448. 

Figure 13.8 Consecutive stages of isothermal crystallization in thin film of nanocomposite iPP/PP-g-MA/o-MMT (87 10 3 by weight), between glass sUdes, at 128°C. Reprinted from Nowacki, R., et al. Spherulite nucleation in isotactic polypropylene based nanocomposites with montmoriUonite under shear. Polymer 2004,45,4877-4892, with kind permission from Elsevier, Copyright 2004.

---