Heterogeneous polymers polymer blends

What is the maximum size, d, of heterogeneity in polymer blend that fulfills the condi-... 

There are a few publications on the use of other spectroscopic techniques such as Brillouin scattering, photoacoustic, and Raman spectroscopy. The primary application of these has been to study the heterogeneities in polymer blends, viz. crystallization or phase separation. 

Solid state nuclear magnetic resonance spectroscopy (NMR), e.g. [107-109]. This technique is sensitive to the local environment of certain nuclei, their mobility and orientation [108]. It provides information about the heterogeneity of polymer blends to c. 5 nm or less (spin diffusion experiments) or c. 0.3 nm in cross-polarization experiments, from which the direct (averaged) distance between two types of nuclei in a sample can be determined [107,108]. Motions of moleuclar groups in a polymer chain can be analyzed and correlations with dispersion areas in the mechanical spectra may be possible [109]. Solid state NMR is not a standard technique at the present time but it is becoming increasingly important. 

When the heterogeneous recycled polymer blends are to be used for applications without a downcycling, the materials must show improved mechanical properties. These can be generated ascertaining fine phase dispersion and intensive interactions between the phases. The method that leads to such improvement of properties is known in polymer blends industry as compatibilization. 

CONDITIONS FOR CARBON BLACK ACCUMULATION AT THE INTERFACE IN HETEROGENEOUS BINARY POLYMER BLENDS... 

One quite reliable microscopic technique that requires no special sample preparation is that of AFM [22,62,63]. In particular, the phase-imaging mode in tapping mode AFM delivers important information regarding the structure and properties of heterogeneous semicrystalline polymer blends. 

In situ preparation of polymer blends of 1,4-polybutadiene with polystyrene, or poly(l-butene) has been achieved by using the heterogeneous Ziegler-Natta type catalyst (C2H )2A1C1—Ti(OC4H )4 in the host polymers (217). Homogeneous catalysts can also be used to catalyze these reactions (218). 

Because graft copolymers are much "easier" to obtain synthetically than heterogeneous diblock or triblock copolymers, they have also been used as compatibiUzers ia polymer blends. Theoretically, they are not as efficient as the diblocks (60), but they are successhilly and economically used ia a number of commercial systems (61). 

Conducting Polymer Blends, Composites, and Colloids. Incorporation of conducting polymers into multicomponent systems allows the preparation of materials that are electroactive and also possess specific properties contributed by the other components. Dispersion of a conducting polymer into an insulating matrix can be accompHshed as either a miscible or phase-separated blend, a heterogeneous composite, or a coUoidaHy dispersed latex. When the conductor is present in sufftcientiy high composition, electron transport is possible. 

Polymer Alloys A class of polymer blends, heterogeneous in nature with modified, controlled interfacial properties or morphology. 

This topic has been mentioned in Section V, Failure, Defect and Contaminant Analysis, in Chapter 15, where a number of typical practical problem invetsigations were presented. Obviously the potential list of examples exhibiting different characteristics and requiring a different type of analysis is lengthy. When the sample is heterogeneous, e.g., a polymer blend or a composite, the study of the surface of a failed piece of material may reveal whether the problem is the interface of the components or that failure occurred within one of these. In particular in the case of crazing or necking orientation may have been induced, the way this can be analysed is discussed in Chapter 8. 

Homogeneous and Heterogeneous Rubbery-Rubbery Diblock Copolymers and Polymer Blends A Unified View... 

Binary fluorides, methods of preparing noble-gas, 77 335-336 Binary heterogeneous polymer blends compliance of, 20 347-348 moduli of, 20 346-347 nonlinear viscoelastic behavior of, 20 348 yield and/or tensile strength of, 20 348-349... 

Binary plutonium halides, 79 689 Binary plutonium oxide, 79 688 Binary polymer blends, 20 330-334, 343. See also Binary heterogeneous polymer blends... 

Heterogeneous particle morphology, in polymer colloids, 20 387 Heterogeneous photocatalysis, 19 73, 103 principles of, 29 74-75 Heterogeneous polymer blends, 20 343. 

Immiscible liquids, static mixing of, 16 715 Immiscible polymer blends, 20 318-319 barrier polymers, 3 396-398 heterogeneous, 20 357-358 Immiscible polymers, compatibilization of, 20 324-325... 

Most of the experiments reported so far have been performed on linear homopolymer systems. In Chap. 6 we discuss what has been achieved so far beyond such simple materials. We begin with the discussion of neutron spin echo data on miscible polymer blends, where the main issue is the dynamic miscibility . There are two questions Firstly, on what length and time scales and to what extent does a heterogeneous material like a blend exhibit homogeneous dynamics Secondly, how does it relate to the corresponding homopolymer properties ... 

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