Non-crystalline phases

Here A/)i is the chemical potential difference between the crystalline and non-crystalline phases. 

The fact that crystalline polymers are multiphase materials has prompted a new approach in characterizing their internal structure (lamellar thickness, perfection, etc.) and relating it to the hardness concept (volume of material locally deformed under a point indenter). In lamellar PE microhardness is grossly a given increasing function of lamellar thickness. In using the composite concept care must be exercised to emphasize and properly account for the non-crystalline phase and its various... 

Chowdhury, M.A.J., Ihara, H., Sagawa, T., and Hirayama, C., Retention versatility of silica-supported comb-shaped crystalline and non-crystalline phases in high-performance liquid chromatography, J. Chromatogr. A, 877, 71, 2000. Chowdhury, M.A., Ihara, H., Sagawa, T., and Hirayama, C., Retention behaviors of polycyclic aromatic hydrocarbons on comb-shaped polymer immobilized-silica in RPLC, J. Liq. Chromatogr. Relat. TechnoL, 23, 2289, 2000. 

The letters a, a , b, represent the ends of molecules in the crystal phase of the micelle, b, the ends of molecules in the non-crystalline phase, / the length of the crystalline phase. 

Hayakawa, R. Relaxation processes in crystalline and non-crystalline phases in polymers. Progress in Polymer Science, Japan, Vol. 3. Tokyo Kodansha 1972. 

In addition to the assumed microhardening of the non-crystalline phases, the crystallization of the PEO soft segments in PEE acts simultaneously in the same deformation range as can be concluded from the analysis of WAXS data (see Fig. 6.6). The scattering curves at = 28.8% and = 58.8% are different from those at lower deformations. Their shape indicates overlapping of two independent reflections from two different unit cells. The lower-angle one arises from the ... 

Physical methods include tuning of chain conformation [39-42] and manipulation of supermolecular structure [43]. Because of its highly coplanar backbone, PFO can be physically transformed into a variety of supermolecular structures [39-42], such as crystalline phases (i.e., a and a phases) and non-crystalline phases (i.e., amorphous, nematic, and /3-phase for /3-phases it has an extended conjugation length of about 30 repeat units as calculated from wide-angle X-ray diffraction measurements) [44]. However, studies on the effects of tuning chain conformation on EL are scarce, but reports on effects of manipulating supermolecular structures on PL behaviors of PFO are extensive [40-42,44]. 

The ability to conduct EXAFS studies on complexes in non-crystalline phases and in particular on active catalyst systems in situ has been the driving force for much of the development and application of the technique to the analysis of cluster geometry. In the earlier phase of this sort of work, i.e. studies of type (iii), the objective was to identify the cluster species present on the support and the nature of the cluster-support interaction. Three general modes of attachment of cluster complexes to supports have been explored ... 

A suitable pulse sequence can then set up a state in which the net magnetisation of the crystalline phase is zero and that of the non-crystal-line phase is in equilibrium with the applied magnetic field Application of a 90° pulse after a time t and analysis of the subsequent FID then allows the determination of the magnetisation M t) of the crystalline phase as a function of time as it relaxes back towards equilibrium by the transference of magnetisation to it by spin diffusion from the non-crystalline phase. 

If the structure is not known to be lamellar, the NMR results are more difficult to interpret. The possibility that the non-crystalline phase is present as rod-like or blob -like (spherical, cubic, etc.) regions must be considered and the interpretation cannot always be unambiguous. The multilayer lamellar stack is itself usually a component within a morphological structure of greater size, which for unoriented polymers is frequently the spherulite. This type of structure is discussed in the next section. 

Sar] Sare, I.R., Two Non-Crystalline Phases in a Splat-Cooled Fe-1.9 mass% Si - 4.2 mass% C Alloy , Scr. Metall, 9, 607-609 (1975) (Experimental, Crys. Stmcture, 7)... 

In Fig. 13, a difference spectrum which was obtained by subtracting the spectrum at t, = 140 jus from the spectrum at t, = 0-5 fi% is shown. The difference spectrum (C) is considered to represent the other non-crystalline component with the contribution from the crystalline component with shorter T. By subtracting the crystalline contribution, we have a rather broad but symmetric lineshape centring at 31-3 ppm, as is indicated by the broken line in curve C. Since the lineshape can be well approximated by a single Lorentzian distribution function, this non-crystalline component is also assumed to comprise a monophase. The very short transverse relaxation time (which disappeared completely within 100/xs) and the downfield chemical shift characterize this non-crystalline phase as comprising somewhat rigid methylene sequences in a trans-rich conformation. 

The highest values of crystallinity achieved after annealing of fibers of CPE-1 and CPE-2 are 35 and 25%, respectively. Both copolymers under study appear to be semicrystalline materials. In contrast to the majority of flexible-chain polymers, the non-crystalline phase of both stiff-backbone copolyesters is not an amorphous but a mesomorphous one. It was shown that this structure may be identified as an ordered LC smectic state. However, the main difference between the non-crystalline structures of CPE-1 and CPE-2 consists in periodic or aperiodic packing of layers within the LC smectic phase, respectively. 

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