Stacked lamellar structure

Provided the crystalline stem length t,c is known and a stacked lamellar structure is assumed, the thicknesses of the interphase and amorphous phase can be evaluated from these data by the Eqs. (6) and (7) ... 

Figure 5.15 Model of structural evolution process in the isothermal crystallization of polyethylene chains. The random chain segments change to the locally regularized trans-form. The stacked lamellar structure is formed with the long period 800 A. The structure changes further to the stacked lamellar structure of 400 A period by inserting the new lamella into the original lamellae. It is noted that the radius of gyration is kept unchanged during this process. (From Reference 46 with permission from the Society of Polymer Science, Japan.)...

In crude oil and water systems asphaltenes are adsorbed at the water-oil interface and flocculate yielding a three-dimensional structured film (as Mesophase C) (43). Such structured films at the W/0 interface were verified by Sif-fert et al. (44). They separated oil, water, and a sticky mass between sheets in asphaltene particles for fliis black mass. These regularly stacked lamellar structures have close similarity to surfactant liquid crystals. 

Figure 5.15 shows the curve X(z). The several characteristic points on this curve give the parameters of the stacked lamellar structure. 

Figure 5.15 (a) Electron density distribution p(z) of the stacked lamellar structural model... 

Figure 5.16 Structural evolution in the isothermal crystallization process of isotactic polypropylene revealed by a combination of infrared and WAXD/SAXS data. Parts of random coils in the melt are regularized to short helical segments, which form higher density domains in the melt. These domains approach gradually as shown by a correlation distance and change into stacked lamellar structure [67].

Figure 5.19 Time dependence of the various structural parameters coiiected by infrared spectra and WAXD/SAXS measurements in the isothermal crystallization of polyoxy-methyiene. It should be noticed that the appearance of FCC, as known from the infrared spectra, occurs at almost the same time as the appearance of the stacked lamellar structure (Li) and the 100 WAXD reflection. The ECC infrared band appeared at around 100 seconds, where the generation of new lameiiar structure was detected [49, 65].

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