Poly three-phase structure

Figures 5.113-115 illustrates the need to parallelize the chains of poly(ethylene terephthalate) applying the three-phase structure, identified in Figs. 5.69-72 [25]. Figure 4.113 shows the model for the combination of the three phases [35,36]. The orientation in the mesophase matrix, measured by its average orientation function (OF) obtained from the X-ray diffraction pattern [24], is of most importance for the modulus and, surprisingly, also for the ultimate strength, as indicated by the left curves...

The three-phase structures 12, 13, and 14 are of particular interest because of the even more severe violation of the phase rule. At constant pressure, in equilibrium, only one-phase areas should be stable. Drawn fibers of poly(ethylene terephthalate) (PET) are discussed as three-phase sttucture with Figs. 5.68-72 and 5.113-115. As in polyethylene, the drawing to fibers or films orients the amorphous nanophase and achieves an arrested mesophase order, proven with Fig. 5.72. Since the drawing of PET fibers is much less efficient in extending the molecules than gel-spinning, there remains a sizeable portion of the amorphous phase, as shown in Fig. 5.71. The mobile mesophase of PET has not been found as a stable phase, as in polyethylene. Copolymers of PET with stiffer repeating units, such as oxybenzoate, however, have stable mesophases (see Chap. 7). 

The problem appears somewhat more complicated in the case of nanocapsules, where one deals with at least three different structural elements a continuous liquid phase, the solid phase represented by the capsule walls and the encapsulated liquid domain All techniques mentioned so far only allow for the differentiation of the solid phase from the two liquid phases. An example for poly-w-butylcyanoacrylate nanocapsules in aqueous dispersion is shown in Figs. 15 and 16. 

Two possible scenarios can be envisaged for the structure of the hybrid material (see Fig. 11). The poly(ethylene oxide) block, albeit strongly interacting and partially penetrating, forms a pure PEO layer at the interface to the hydrophobic poly(isoprene) (Fig. 11, left-hand sketch) ( three-phase system). The other possibility is the complete dissolution of the PEO chains in the aluminosilicate, which results in the two-phase system depicted in the right-hand sketch of Fig. 11. Spin-diffusion NMR experiments showed that there appears to be no dynamic heterogeneity in the poly(ethylene oxide) chains, as would be expected for a three-phase system, giving rise to the conclusion that the hydrophilic... 

A degree of compatibility between polymers is introduced by IPN formation as two polymers are interlocked in a three-dimensional structure during synthesis. The phase domains are smaller in higher compatibility systems. Most of the early IPN studies were based on immiscible polymers and a small gain in phase mixing was observed. Frisch and coworkers prepared IPNs from PS and poly(2,6-dimethyl-l,4-phenylene oxide), which were miscible. Klempner prepared IPNs that contained opposite charges, and showed better miscibility than IPNs without charge. 

Epitaxy of Isotactic Poly (1-butene) Isotactic poly(1-butene) (iPBul) is an archetypical polymorphic polymer with three different structures that differ by the chain conformation, and thus by the unit-cell geometry and symmetry (cf Chapter 2).The three crystal phases could be obtained by epitaxial crystallization on appropriate substrates [48-50]. Most interesting among them are the epitaxy of Form I (trigonal unit cell, threefold helical conformation, racemic phase) and that of Form III (orthorhombic unit cell, fourfold helical geometry, chiral crystal phase). 

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