Polymer science crystallinity

Generally, polymers are classified as either amorphous or crystalline. A solid amorphous material that has no significant order on the molecular scale is characterized as a glass. Other polymers are characterized as crystalline, but this does not mean that the entire sample is crystalline, as implied by a crystalline sample of a molecular solid. Rather, in polymer science "crystalline" implies that some small regions of the material, termed domains, are crystalline and have the ability to diffract x rays. Polymers are rarely fully crystalline... 

Polymers can exist in the crystalline and amorphous regions, and the crystallinity of polymeric fibers is one of the most important aspects of polymer science. Crystallinity is a measure of the percentage of crystalline regions in the polymer with respect to amorphous region. Rgure 1.8 is a schematic representation of polymer chains in the crystalline and amorphous regions. 

New lonomer Types. There is a continuing interest in new ionomers within the academic community, since novel and unexpected phenomena are frequently being discovered. However, there are still many unanswered questions with respect to the ethylene ionomers, especially the influence of ionic bonding on crystalline stmcture. Continued study of these interesting polymers will close the gaps in knowledge of this area of polymer science. 

In concluding this discussion, it is important to point out that crystalline polymers can be polymorphic because of slight differences in the conformation of the helical disposition of stereoregular polymer chains the polymorphism is attributable to differences in the weak intermolecular bonds. This abstruse phenomenon (which does not have the same centrality in polymer science as it does in inorganic materials science) is treated by Lotz and Wittmann (1993). 

Inoue, T., Thermotrophic liquid crystalline polyacrylates, in Progress in Pacific Polymer Science, Imanishi, Y. (Ed.), Spring-Verlag, Berline, 1992, Vol. 2, pp. 261-272. 

Provder, T. 2006. Film Formation, Process, and Morphology. Oxford University Press, New York. Rudin, A. 1998. Elements of Polymer Science and Technology, 2nd ed. Academic, Orlando, EL. Shibaev, V. and Lam, L. 1993. Liquid Crystalline and Mesomorphic Polymers. Springer, New York. Sinha, R. 2002. Outlines of Polymer Technology Manufacture of Polymers and Processing Polymers. Prentice-Hall, Englewood Clifts, NJ. 

Figure 1.66 Resolution of the X-ray scattering curve of a semicrystalline polyethylene sample into contributions from crystalline (110 and 200 planes) and amorphous components. From F. W. Bilhneyer, Textbook of Polymer Science, 3rd ed. Copyright 1984 by John Wiley Sons, Inc. This material is used by permission of John Wiley Sons, Inc.

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

McFarlane, F. E., Nicely, V. A., Davis, T. G. Liquid crystal polymers. II. Preparation and properties of polyester exhibiting liquid-crystalline melts, in Contemporary Topics in Polymer Science, Vol. 2 (ed.) Pearse, E. M., Schaefgen, J. R., p. 109, London, Plenum 1977... 

An important objective in materials science is the establishment of relationships between the microscopic structure or molecular dynamics and the resulting macroscopic properties. Once established, this knowledge then allows the design of improved materials. Thus, the availability of powerful analytical tools such as nuclear magnetic resonance (NMR) spectroscopy [1-6] is one of the key issues in polymer science. Its unique chemical selectivity and high flexibility allows one to study structure, chain conformation and molecular dynamics in much detail and depth. NMR in its different variants provides information from the molecular to the macroscopic length scale and on molecular motions from the 1 Hz to 1010 Hz. It can be applied to crystalline as well as to amorphous samples which is of particular importance for the study of polymers. Moreover, NMR can be conveniently applied to polymers since they contain predominantly nuclei that are NMR sensitive such as H and 13C. 

Burmester A, Geil PH (1972) Small angle diffraction from crystalline polymers. In Pae RD, Morrow DR, Chen Y (eds) Advances in polymer science and engineering. Plenum, New York, pp 42-100... 

Order and Mobility are two basic principles of mother nature. The two extremes are realized in the perfect order of crystals with their lack of mobility and in the high mobility of liquids and their lack of order. Both properties are combined in liquid crystalline phases based on the selforganization of formanisotropic molecules. Their importance became more and more visible during the last years in Material science they are a basis of new materials, in Life science they are important for many structure associated functions of biological systems. The main contribution of Polymer science to thermotropic and lyotropic liquid crystals as well as to biomembrane models consists in the fact that macromolecules can stabilize organized systems and at the same time retain mobility. The synthesis, structure, properties and phototunctionalization of polymeric amphiphiles in monolayers and multilayers will be discussed. 

A relatively recent field in polymer science and technology is that of the polymeric liquid crystals. Low molecular liquid crystals have been known for a long time already they were discovered almost simultaneously by Reinitzer (1888) and Lehmann (1889). These molecules melt in steps, the so-called mescrphases (phases between the solid crystalline and the isotropic liquid states). All these molecules possess rigid molecular segments, the "mesogenic" groups, which is the reason that these molecules may show spontaneous orientation. Thus the melt shows a pronounced anisotropy and one or more thermodynamic phase transitions of the first order. 

Chapoy LL (Ed), "Recent Advances in Liquid Crystalline Polymers", Elsevier Appl Science Publisher, London, 1985. Ciferri A, Krigbaum WR and Meyer RB, (Eds) "Polymer Liquid Crystals", Academic Press, New York, 1982. Gordon M and Plate NA (Eds), "Liquid Crystal Polymers", Advances in Polymer Science 59, 60 and 61, Springer, Berlin and New York, 1984, (with important contributions of Flory PJ Uematsu I and Y Papkow SP Ober CK, Jin JJ and Lenz RW Wunderlich B and Grebowicz J Dobb M and McIntyre JE Finkelmann H and Rehage G and Shibaev VP and Plate NA). 

One of the most important subjects of applied polymer science is the understanding of the deformation mechanisms and the fracture properties of semi-crystalline polymers. At the same time, it is one of the most diffictdt to study, and the amount of research in this area is high (see e.g. One of the complications experienced with semi-crystalline polymers stems from the fact that they are composed of crystalline and amorphous phases, arranged in a diversity of microstructures. These are generally... 

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