Inter-lamellar amorphous phase

The fact that the thickness of the inter phase estimated here stays unchanged at 34A in the molecular weight range of 30,000-100,000, while the mass fraction and thickness of amorphous phase change remarkably, is particularly meaningful. Flory et al. [6,7] anticipated in 1984 based on their lattice theory that the methylene chains that emerge from the basal plane of lamellar crys-... 

The sphemlitic growth rate, the overall crystallization rate, and the melting temperature of PB-1 are depressed by the presence of HOCP. The verified HOCP interferences on the kinetics of PB-1 crystal transformation from form II to form I indicate that in the crystallized mixtures the HOC molecules are rejected in inter-lamellar and/or interfibriUar regions of PB-1 spherulites where, dependening on the blend composition, they can form a homogeneous mixture with uncrystaUized PB-1 molecules or a conjugated amorphous phase, one rich in PB-1 component and the other rich in HOCP component. 

The exact location of the plasticizer is frequently evaluated to better understand the structure of plasticized polymers. In poly[(vinylidene fluoride)-co-hexafluoropropene], VDF/HFP plasticized with dibutyl phthalate, SAXS measurements indicate that DBP resides in the amorphous zone outside the lamellar stacks. If ciystallization is slow the inclusion of DBP inside the lamellar stacks is also possible. In another contribution for the same copolymer, plasticizer was also found in amorphous phase close to the interface with crystalline stmctures which was evidenced by almost constant spacing in the range of tricresyl phosphate studied.In the plasticized PVC, the plasticizer molecules were found in the amorphous area but were also present in the interlamellar, intefibrillar, inter-spheralitic regions and in the amorphous fold surfaces. ... 

The compact interlacing of crystalline and amorphous regions within typical PEO-based polymer electrolytes could well account for the characteristic impedance plots obtained for these materials [20]. Such plots are characterized (Figure 1.4) by depressed semi-circles and tilted spikes, indicative of constant phase element (CPE) behaviour. A CPE can be thought of as a leaky capacitor such as could be formed by a thin imperfect dielectric (the crystalline lamella) separating the amorphous, inter-lamellar conducting regions. 

SWD for other polymer, namely poly (butylene isophthalate)(PBI) [49], and the corresponding (Z e) orm data are also included in Fig. 21.13 for comparison. One may propose the idea that in the second regime, which we can associate with the secondary crystallization, crystalUzation takes place essentially in the inter lamellar stacks amorphous phase. These secondary crystals should be arranged either as independent lamellae or as very defective stacks. This mechanism should not produce significant amounts of RAP because, as previously discussed, the RAP can be assigned to an intra lamellar stacks amorphous phase. Additional support for this model on the basis of structural experiments has been discussed extensively for PBI [49]. A similar view has been recently proposed to explain secondary crystalUzation in poly(ethylene isophthalate-co-terephtalate) copolymers crystallized from the melt [50]. 

Under irradiation up to medium doses mainly crosslinking occurs in the amorphous, inter-lamellar phases, resulting in increased strength and stiffness and reduction in strain at break. 

Figure 12.29 Schematic representation of epitaxially oriented cross-hatched lamellar structure, in which the mechanically soft amorphous inter-lamellar regions of one phase are bridged by the crystalline lamellae of the other phase. Lotz and Wittmann [94]. Reproduced with permission of American Chemical Society.

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