Morphology of polymer materials

Since its introduction in the early 1970s, the small angle neutron scattering (SANS) method has had a substantial impact on polymer research. When used with partially deuterated polymers, SANS permits a close monitoring of macro-molecular conformations in polymer solutions, melts, and blend mixtures. This advantage has made it a unique tool for the understanding of the morphology of polymer materials and of the relationship between their structures and physical properties. 

There are many different ways of using fluorescence quenching techniques to study the morphology of polymer materials, even those of rather complicated composition. Important considerations are (i) the use of synthesis to introduce the dye as a sensor into a specific phase of the material (ii) the spectroscopic... 

Microscopy is the study of the fine structure and morphology of objects with the use of a microscope. Microscopes range from optical microscopes, which resolve details on the micrometer level, to transmission electron microscopes that can resolve details less than one nanometer across. The size and visibility of the polymer structure to be characterized generally determines which instrument is to be used. For example, the size and distribution of spherulites can be observed by optical techniques, but a study of their internal structure requires electron microscopy. Combinations of the various microscopy techniques generally provide the best insight into the morphology of polymer materials [1]. Table 2.1 shows the basic properties of the different microscopes, for the purpose of comparison. 

Tourillon and Gamier [428] found using SEM that the morphology of the material is affected by the nature of the dopant anion and that there is considerable swelling of the polymer on doping (with increases in thickness of the order of 40% for... 

As already mentioned, the results and rules found in dependencies of properties with the morphology of polymeric materials are in most cases limited to special classes of polymers or even one polymer species only. Therefore, the intention of this subsection can only be to demonstrate the potential and the possibilities which exist to influence the properties of polymers by modification of their morphology. This will be done with relevant examples that are described in detail in Chaps. 2-5. 

Keith HD (1986) Morphology of polymers. In Bever MB (ed) Encyclopedia of materials science and engineering. Pergamon, New York, p 3110... 

In this review, we introduce another approach to study the multiscale structures of polymer materials based on a lattice model. We first show the development of a Helmholtz energy model of mixing for polymers based on close-packed lattice model by combining molecular simulation with statistical mechanics. Then, holes are introduced to account for the effect of pressure. Combined with WDA, this model of Helmholtz energy is further applied to develop a new lattice DFT to calculate the adsorption of polymers at solid-liquid interface. Finally, we develop a framework based on the strong segregation limit (SSL) theory to predict the morphologies of micro-phase separation of diblock copolymers confined in curved surfaces. 

Immiscibility of polymers in the melt is a common phenomenon, typically leading to a two-phase random morphology. If the phase separation occurs by a spinodal decomposition process, it is possible to control the kinetics in a manner that leads to multiphase polymeric materials with a variety of co-continuous structures. Common morphologies of polymer blends include droplet, fiber, lamellar (layered) and co-continuous microstructures. The distinguishing feature of co-continuous morphologies is the mutual interpenetration of the two phases and an image analysis technique using TEM has been described for co-continuous evaluation.25... 

Films of pure PPX and PPX composites with nanoparticles of various metals resulted from cryochemical solid-state synthesis were studied by the dielectric spectroscopy method [104], Dielectric spectroscopy has proven very useful for studying the structure and dynamics of polymer materials as well as the transport mechanism of charge carriers. To study features of the polymer structure dielectric test methods were used due to their high sensitivity to morphological changes. 

Photo-DSC on the other hand, is a much more recent technique which has been developed thanks to technological developments in thermal analysis and coupled techniques. Until very recently, it has been used mainly to study photopolymerization or photocuring reactions by measuring the heat of reaction. We proposed the use of this powerful technique to study polymer photo-aging, using the photo-DSC as an accelerated aging device and coupled in situ analysis of the modification of the morphology of the materials. In this case, the crystallizability of the polymer is used as an indicator of the structural modifications. 

So far in this book, we have focused on aspects of polymer synthetic chemistry and what can be considered local structure, the arrangements of units in a chain and how these can be characterized spectroscopically. In the next few chapters our focus shifts to a more global scale and involves the physics and physical chemistry of polymer materials. We will start with the shapes or conformations available to chains in solution and the solid state, how these chains interact with one another and other molecules (e.g., solvents), and the- conditions under which chains can organize and aggregate into larger scale structures, as in crystallization (or, more briefly, some of the fascinating morphologies formed by block copolymers). 

In literature the following methods of preparation of polymer material specimen and studying their morphology are described methods of ultrathin section and films with contrasting of osmium tetroxide (10.11). method of replication of the brittle fractur-ed surface (11.12) oxygen and chemical etch of the polished surface or the fractured surface with the following replication for electron microscopy (11. 

The second half of this volume is reserved to a discussion of specific craze problems encountered in practical application of polymer materials. J. A. Sauer and C. C. Chen analyze the fatigue behavior (mostly of rubber modified polymers). They show quantitatively the important effects of test variables and sample morphology on fatigue response. K. Friedrich gives an overview on the shear and craze phenomena in semicrystalline polymers. 

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