Crystalline domains, definition

Due to their higher dimensions, the macromolecules may successively penetrate several crystalline domains, thus interconnecting them. The spaces between these crystalline regions do not have a ordered structure, any longer, appearing as amorphous regions. In practice, there are no polymers with 100% crystallinity degree. The correct and common definition of these polymer types is semicrystalline polymers . 

A crystalline polymer above Tg is a flexible thermoplastic. On raising the temperature further, a second relatively sharp transition occurs at the melting temperature (Tm). It is at this point that the crystalline domains melt, and above T the material is a liquid. By definition, an elastomer is a polymer in the temperature range between Tg and T. ... 

Further tests with various metals having different types of crystalline domains will have to be conducted before this electrolytic erosion can be definitely verified. However, past studies by various investigators tend to indicate that some erosive action other than high intensity mechanical forces are necessary to produce the high rate of deterioration and specific erosion patterns observed in hydraulic pumps and other equipment subject to severe cavitation. 

Although this definition still fits most materials called IPNs, now some hybrid polymer blends, such as thermoplastie ayyarent IPNs, call for a broader concept [3,7,8]. In contrast to the chemically crosslinked IPNs, physical bonds are characteristic of the crosslinking in thermoplastic apparent IPNs. These physical bonds are glassy domains of block copolymers, ionic clusters in iono-mers, or crystalline domains in semicrystalline polymers. The components of thermoplastic IPNs are capable to form physical networks and are characterized by interpenetration of phases. Thermoplastic apparent IPNs take an inter-... 

It is important to bear in mind that Structure Levels I and II are primarily properties of the polymer whereas levels III and IV are properties of the membrane. These definitions are arbitrary and additional levels of structure can be used to describe membrane properties. For example, it may be useful to have levels of structure relating to crystalline-noncrystalline properties, globular domains, pore character and orders of symmetry that can give rise to periodic structures, specific coil character and other important structural details. 

The crystalline and noncrystalline phases in polyamide fibers do not appear to be governed by what may be defined as thermodynamie equilibria, nor is there evidenee for definite boundaries between a phase, characterized by a simple or complex state of order and an essentially amorphous phase. It is therefore quite obvious that the morphological structure of nylons cannot be described adequately in terms of a simple two-phase model according to which ideally ordered crystallites exist together with eompletely amorphous domains. This model constitutes merely one of the two limiting cases the other is that of a paracrystal according to which all deviations from the ideal crystal are ascribed to defects and distortions of the crystal lattice [275-277]. 

Definition of terms related to polymer blends, composites, and multiphase polymeric materials This recommendation defines the most commonly used terms encountered when dealing with polymer blends and composites and is limited to mixtures in which the components differ in chemical composition or molar mass or both and in which the polymer forms the continuous phase. Many of the multiphase systems are in fact biphasic systems with a multitude of finely dispersed phase domains. Crystalline and liquid crystalline multiphase systems are the subject of other documents. 

It is also clear that activity of a filler should be related to any definite property of material. It was proposed to introduce the concept of structural, kinetic, and thermod3uiamic activity of fillers. Structural activity of a filler is its abihty to change the polymer structure on molecular and submolecular level (crystallinity degree, size and shape of submolecular domains, and their distribution, crosslink density for network pol3rmers, etc.). Kinetic activity of a filler means the ability to change molecular mobility of macromolecides in contact with a solid surface and affect in such a way the relaxation and viscoelastic properties. Finally, thermodynamic activity is a filler s ability to influence the state of thermodynamic equilibrium, phase state, and thermodynamic parameters of filled polymers — especially important for filled poljmier blends (see Chapter 7). 

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