Polymer morphology conformation

Rotations around torsional barriers induce changes in chain conformation. For conjugated systems like polydiacetylenes, flow-induced changes in chain conformation can have a profound influence on the photon absorption and electronic conductivity properties of the material [73]. Flow-induced changes in molecular conformation form the basis for several technically important processes, the best known examples are the production of oriented fibers by gel spinning [74], the compatibility enhancement [75] and the shear-induced modification of polymer morphology [76]. 

RO Loutfy. In MA Winnik, ed. Photophysical and Photochemical Tools in Polymer Science Conformation, Dynamics, Morphology. NATO ASI Series, Series C 182. Dordrecht, The Netherlands D. Reidel, 1986, p 429. 

At a higher structural level, the intercrystalline structures or the polymer morphology will be examined. These structures result from the crystal growth habit of the polymer. Most of the published work in this field relates to structures at the molecular level and, in particular, to the polymer chain conformation. The chain conformation is of particular interest, because it is strongly coupled to the electronic structures and the very interesting UV absorption characteristics of these polymers. 

M. A. Winnik (Editor), NATO Advanced Science Institutes Series Series C, Mathematical and Physical Sciences, Vol. 182 Photophysical and Photo-chemicl Tools in Polymer Science. Conformation, Dynamics, Morphology,... 

Rgure 8.6 Representation of the variety of polymer morphologies in solution and in the gel (or microgel) or solid states. In solution the conformation of the polymer depends on the nature of polymer-solvent interactions and whether or not the polymer chains associate to form micellar aggregates. Crystals of polymer and microcrystals can be prepared, and gels can be formed from covalently crosslinked or polymer chains associated by hydrogen bonding or hydrophobic interactions. Listed are the forms in which most polymers can be fabricated membranes, fibres, composites, matrices microspheres and microcapsules can also feature, as discussed later in this chapter. 

While machine control is important, it is the polymer state (pressure, temperature, and morphology) that directly determines the molded part quality. As such, recent technology developments have focused on closing the loop between the machine parameters and the polymer state. Conformal cooling and pulsed cooling are two molding technologies that have been... 

In 1962 Dr. Bovey joined Bell Laboratories as a member of the technical staff, and was appointed to his present position in 1967. He continued his detailed studies of polymer structure and conformation at Bell Laboratories, and extended the scope of his work to include investigations of nuclei other than protons, branch analyses in polyethylene, and determination of defect structures in vinyl and related polymers. He continues to have a vigorous research program in the areas of polymer conformations in the solid state, polymer morphology, and the mechanisms of polymer stabilization and degradation. 

Kister, G., Casstmas, G. and Vert, M. (1989) Effects of morphology, conformation and configuration on the IR and Raman spectra of various poly(lactic add)s. Polymer, 39,267-273. 

Fourier transform infrared (FTIR) spectroscopy is a powerful and reliable technique that for many years has been an important tool for investigating chemical processes and structures. In the polymer fields, FTTR data is used in order to study characterization of chemical bonds, polymer microstructure, chain conformation, polymer morphology, crystallinity and etc, consequently is useful in SPR studies. 

Most of crystalline polymer materials exhibit multi-scale hierarchical structures. At the scale of 0.1 nm, the polymer chains contain regular sequences. At the scale of 0.5 nm, they form stable helical conformations, which then pack together in a compact parallel fashion to make the periodic lattice structure, with the unit cell at the scale of 1 nm. At the scale of 10 run, the folded-chain lamellar crystals are formed for the flexible polymer chains. At the scale of micrometers or larger, the lamellae further assemble into spherulites. Such hierarchical structural characteristics at varying length scales of polymer morphologies are illustrated in Fig. 10.7. 

Thickness of the slit/film can have a drastic effect on the polymer morphology. In Fig. 11 the same 55% PL64 in water system was confined in between two different slits. The bulk morphology of this system is cylindrical, Figs. Ic, 2c, and 6. Adopting conformational freedom the system develops into cylinders, which are either parallel or perpendicular to the wall, depending on the slit width. 

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