Multi-Component Polymer Materials

Polymer-polymer miscibility is usually characterised [1,5,6] by investigating the optical appearance, morphology, glass transition temperature or the crystalline melting behaviour of the blend [38,39]. A blend of two amorphous polymers with different refractive indices will be judged to be miscible if it is optically clear. Measurement of the glass transition temperature, or temperatures, of a polymer blend is the most convenient and popular way of investigating polymer-polymer miscibility. 

It is known [6] that poly(styrene-co-acrylonitrile), SAN, is miscible with PMMA when the acrylonitrile content is between 10 and 30 wt%. To check 

For most polymer pairs to be miscible, an exothermic interaction is required. Nandi et al. [40] studied the miscibility of poly(methyl acrylate) (PMA) and poly(vinyl acetate) (PVAc) in several solvents by the inverse 

The ACp term is a significant parameter because it appears in the Ehrenfest equation [42]. Perhaps, in polymer blends, the intermolecular contribution to ACp plays a more important role than in many common homopolymers and copolymers. 

To date, many supposedly miscible polymer pairs [5,6,13,14,42] have been reported in the literature. However, in some cases [13,14], the breadth of the glass transition region, ATg, taken as the difference between the onset and completion temperatures, is quite broad. For some blend systems, ATg values approach 100°C [13,14]. The transition region may also be 

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Gebizlioglu OS, Argon AS, Cohen RE (1986) In Paul DR, Sperling LH (eds) Multi-component polymer materials. ACS, Washington DC, p 259... 

Three major scattering methods exist for the determination of the morphology in multi-component polymer materials ... 

D. R. Paul and L. H. Sperling, Eds, Multi-component Polymer Materials, Adv. Chem. Ser. No. 211 (American Chemical Society, Washington, DC, 1986). 

Rgure 12.35 (1) summarizes the state of the art of polymeric and multi-component polymer materials from the point of view of the role of surfaces and interfaces. The three main types of surfaces and interfaces are (a) free surfaces, (b) polymer blend interfaces, and (c) polymer composite interfaces. While the dilute solution-colloid interfaces are noifree in the ordinary sense, the fluid phase exhibits a low viscosity allowing rapid diffusion similar in some ways to the free air surface, and is classified as such for the present purposes. The concepts of polymer blends and composites will be further developed in Chapter 13. 

Sperling L H (1986) Multi-Component Polymer Materials, Adv Chem Ser No. 211, ACS Books, Washington, DC. 

Let us now turn to the stateof the art of nomenclature in multi-component polymers (2-7). Many simple materials already have precise names. For example, poly(butadiene-b-styrene) is represented by the structure in Equation 1, where A stands for the butadiene mer and B represents the styrene mer in block copolymer arrangement, as indicated by the small -b-. 

Over the last several years, an enormous amount of experimental and theoretical effort has been focused on multi-component polymer systems as a means for producing new materials on the micron and nanometer scale with specifically tailored material, electrical and optical properties. Composite polymer particles, or polymer alloys, with specifically tailored properties could find many novel uses in such fields as electro-optic... 

At this point it will not be necessary to provide details of polymer blends, nor of their fabrication routes and applications, as this entire book is devoted to such information. Indeed, a plethora of reference material describing different aspects of the materials science and engineering of polymer blends is available [1-11], with many references - both direct and indirect - being made to electron microscopy (EM) and/or atomic force microscopy (AFM) for such purpose. But this simply highlights the significance of microscopy in the characterization of multi-component polymers, polymer blends, and their composites. 

Multicomponent melts that are commonly found in such varied situations as material fabrification, reinforcement, blending, and so on are discussed in the chapter by Muller ( Computational Approaches for Structure Formation in Multi-component Polymer Melts ). Only equilibrium properties are discussed along with computational approaches for coarse-grained models in the mean field approximation. Both hard-core and soft-core models are used to cover a multitude of scales of length, time, and energy. Attention is also paid to methods that go beyond the mean field approximation. 

NMR spectroscopy is one of the most widely used analytical tools for the study of molecular structure and dynamics. Spin relaxation and diffusion have been used to characterize protein dynamics [1, 2], polymer systems[3, 4], porous media [5-8], and heterogeneous fluids such as crude oils [9-12]. There has been a growing body of work to extend NMR to other areas of applications, such as material science [13] and the petroleum industry [11, 14—16]. NMR and MRI have been used extensively for research in food science and in production quality control [17-20]. For example, NMR is used to determine moisture content and solid fat fraction [20]. Multi-component analysis techniques, such as chemometrics as used by Brown et al. [21], are often employed to distinguish the components, e.g., oil and water. 

The past two decades have produced a revival of interest in the synthesis of polyanhydrides for biomedical applications. These materials offer a unique combination of properties that includes hydrolytically labile backbone, hydrophobic bulk, and very flexible chemistry that can be combined with other functional groups to develop polymers with novel physical and chemical properties. This combination of properties leads to erosion kinetics that is primarily surface eroding and offers the potential to stabilize macromolecular drugs and extend release profiles from days to years. The microstructural characteristics and inhomogeneities of multi-component systems offer an additional dimension of drug release kinetics that can be exploited to tailor drug release profiles. 

After numerous answers were brought to the synthetic challenge itself, there arose ever more insistently the quest for functions and properties of such special compounds. Already, even if still far from real applications, one can imagine, based on interlocked, threaded or knotted multi-component molecules, new organic materials, specific polymers, molecular devices or machines able to process and transfer energy, electrons or information. 

Subject areas for the Series include solutions of electrolytes, liquid mixtures, chemical equilibria in solution, acid-base equilibria, vapour-liquid equilibria, liquid-liquid equilibria, solid-liquid equilibria, equilibria in analytical chemistry, dissolution of gases in liquids, dissolution and precipitation, solubility in cryogenic solvents, molten salt systems, solubility measurement techniques, solid solutions, reactions within the solid phase, ion transport reactions away from the interface (i.e. in homogeneous, bulk systems), liquid crystalline systems, solutions of macrocyclic compounds (including macrocyclic electrolytes), polymer systems, molecular dynamic simulations, structural chemistry of liquids and solutions, predictive techniques for properties of solutions, complex and multi-component solutions applications, of solution chemistry to materials and metallurgy (oxide solutions, alloys, mattes etc.), medical aspects of solubility, and environmental issues involving solution phenomena and homogeneous component phenomena. 

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