Crystallization kinetics, role

When considering the results obtained in the present investigation, it seems quite difficult to account for the occurrence of stacking faults in the framework of pentasils simply by the different molecular size of the tetralkylammonium cations trapped within the pores. In fact, the phenomenon occurs in the presence of tetrabutylammonium or tetramethylammonium cations which have the largest and the smallest molecular size, respectively, among the organic bases investigated. It is possible that crystallization kinetics or hydrophilicity of the quaternary ammonium cations play some role. In any case, additional experiments are needed to provide a reasonable explanation. 

Solvent plays a critical role in the development of crystaUization. It can affect strongly the final PSD and crystallization kinetics. However, a solvent is still selected primarily through empirical screening and may be dictated by a previous or subsequent step in the process. Also shown in this example is the impact of supersamration on PSD and form (solvate, oil, and crystalline solid). 

On the basis on the carried out structural investigations of amorphous PET fibers simultaneous heat - mechanically modified at isothermal conditions and constant strain stress values it can be make the following conclusions The mechanical strain force applied simultaneously with the linear heating of the studied PET yarns affects significantly the deformation behaviour and samples crystallization kinetics. Moreover in contrast to the results obtained in the first experiment, all of the so treated specimens are partially crystaUine. The role of the tensile stress in the adjustment of the interacting processes of the fluid like deformation and stress-induced crystallization clearly reveals in the ultimate samples deformation. At stress values from 1.56 MPa to 2.16 MPa predominates the fluid like fibers extension, while the further stress increasing leads to the earlier crystallization start and thereby to decrease of the final fibers length. 

Operation conditions also influence Tref results. Our recent work [29] showed that crystallization kinetics plays an important role in the fractionation process. The CR, the heating rate, and the solvent flow rate can affect Tref profiles to a large extent. We demonstrated that there is a general relationship between Tref profiles and the relative ratio among the CR, the heating rate, and the solvent flow rate ... 

Processing operations such as injection and compression moulding, extrusion, fibre spuming, etc. are likely involved for the preparation and commercialization of polymer/clay nanocomposites. The flow applied during processing play a decisive role in crystallization kinetics and in the morphology obtained. For neat polymers, it has been demonstrated that the flow accelerates crystallization kinetics when compared with the quiescent melts (Keller and Kolnaar 1997 Kumaraswamy et al. 1999) and some crystallization mechanism has been proposed (Somani et al. 2000 Seki et al. 2002), whereas for polymer/clay nanocomposites, studies are still lacking and most of results have been reported for iPP and nylon 6/clay nanocomposites. 

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