Isotactic polypropylene shear-induced crystallization

Nogales, A., Hsiao, B.S., Somani, R.H., Srinivas, S., Tsou, A.H., Balta-Callja, F.J. and Eqzuerra, T.A. (2001) Shear-induced crystallization of isotactic polypropylene with different molecular weight distributions in situ small- and wide-angle X-ray scattering studies, Polymer 42(12), 5247-5256... 

Among the three known crystalline structures (a, j3, y) of isotactic polypropylene (PP), the -modification is certainly the most fascinating one. While the stable a-structure develops under standard process conditions, the occurrence of the /J-form has to be forced (i) by directional crystallization in a temperature gradient field [1-3] (ii) by shear-induced crystallization [4-12] or (iii) by the addition of specific nucleating agents [13-31]. This latter technique is preferred at the industrial scale. 

P. Deng, K. Liu, L. Zhang, H. Liu, T. Wang, J. Zhang, Micro and macro injection molded parts of isotactic polypropylene/polyethylene blends Shear-induced crystallization behaviors and morphological characteristics. J. Macromol. Sci. Part B Phys. 53, 24-39 (2014)... 

Rozanski, A., Monasse, B., Szkudlarek, E., Pawlak, A., Piorkowska, E., Galeski, A., Haudin, J.M. Shear-induced crystallization of isotactic polypropylene based nanocomposites with montmorillonite. Eur. Polym. J. 45, 88-101 (2009)... 

Li Z M, Li L B, Shen K Z, Yang M B and Huang R (2005) In situ poly(ethylene terephthalate) microfibers- and shear-induced non-iso thermal crystallization of isotactic polypropylene by online small angle X-ray scattering, Polymer 46 5358-5367. 

Seki M, Thurman DW, Oberhauser JP, Komfield JA (2002) Shear-induced orientation in the crystallization of an isotactic polypropylene nanocomposite. Macromolecules 35 2583 Siddiqui MA, Ahmed Z (2005) Mineralogy of the Swat kaolin deposits, Pakistan. Arab J Sci Eng 30 195-218... 

Xu JZ, Chen T, Wang Y, Tang H, Li Z-M, Hsiao BS (2011) Graphene nanosheets and shear flow induced crystallization in isotactic polypropylene nanocomposites. Macromolecules 44 2808... 

Li L, de Jeu WH. Shear-induced smectic ordering as aprecursor of crystallization in isotactic polypropylene. Macromolecnles 2003 36 4862-4867. 

Somani RH, Yang L, Sics I, Hsiao BS, Pogodina NV, Winter HH, Agarwal P, Fruitwala H, Tsou A. Orientation-induced crystallization in isotactic polypropylene melt by shear deformation. Macromol Symp 2002 185 105-117. 

Larin B, Avila-Orta CA, Somani RH, Hsiao BS, Marom G (2008) Combined effect of shear and fibrous fillers on orientation-induced crystallization in discontinuous aramid fiber/isotactic polypropylene composites. Polymer 49(l) 295-302... 

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