Polymerization exotic

Growing macrocations can rearrange to more stable structures when structural requirements for this are met and the lifetimes of the individual macrocations are relatively long. The monomeric unit isomerizes by intramolecular reaction under these conditions. Since the monomeric units of the polymer produced can often not be produced by existing monomers, these polymerizations are called phantom or exotic polymerizations. They can proceed by ring isomerization or by material transport. ... 

Intramolecular transfer reactions are possible with cationic polymerizations. This leads to an isomerization of the monomeric unit. Since the monomeric unit of the resulting polymer often cannot be produced by polymerization of the monomer or unimer of this polymer, reactions of this type are also referred to as phantom or exotic polymerizations. At low temperatures, the isomerization polymerization is preferred to normal propagation, and here two types can occur. An isomerization of bonds occurs in the transannular polymerization of norbornadiene ... 

Exothermic chemical reactions, 25 299-301 catalytic converter, 10 45 formaldehyde manufacture by, 12 115 temperature-dependent enthalpy changes for, 25 303-305 Exothermic polymerization, 10 709 Exotic radioactive decays, 21 305-306 Expandable polystyrene (EPS),... 

The concept of electric transport in polymers due to the availability of polymeric materials with characteristics similar to those of metals is certainly fascinating and, indeed, many studies have been directed towards the preparation and the characterisation of these new electroactive conductors. The final goal is their use as new components for the realisation of electronic and electrochemical devices with exotic designs and diverse applications. 

The processing techniques used for CMCs can be quite exotic (and expensive), such as chemical vapor infiltration (CVI), or through pyrolysis of polymeric precursors. Their maximum use temperatures are theoretically much higher than most MMCs or PMCs, exceeding 1800°C, although the practical use temperature is often much lower... 

Since this discovery a number of binuclear complexes of this type have been isolated, including the arsenic analog of the above (57) and compounds prepared from more exotic ylide precursors (58-60). A polymeric gold(I) complex was obtained by reaction of [AuCl(PMe3)] with the biden-tate ylide CH2=PMe2(CH2)6PMe2=CH2 (60). 

Another exotic feature of emulsion polymerization in a CSTR is that sustained oscillations are frequently observed in... 

Many centres with a formal positive charge on nitrogen have already been described, especially with polymerizations of more or less exotic monomers. 4,5-Dihydro-l,3-oxazine is transformed to polymer by the overall reaction... 

Considerable interest also has been directed at the use of multicomponent composites where, in theory, the most useful properties from each phase can be realized in the whole. This includes metallodielectric structures where a metallic phase imparts, for example, a high index or more exotic effect (e.g., plasmon resonance) and a low-loss or property-tunable dielectric phase. The dielectric phase can be ceramic or polymeric and also has included ferroelectric polymers, embedded nanoparticles, and organic/inorganic hybrids. ... 

Numerous enzymes have been employed as polymerization catalysts in these exotic solvents. Table 13.1 outlines the enzymes discussed in this chapter, along with the application and the acronym or abbreviation that will be used throughout this report. 

This chapter explores the application of biocatalytic polymerization in exotic solvents. These solvents are often termed unconventional , in that they would not generally be considered as a polymerization media. However, their use over the previous decade has dramatically increased due to the international push for cleaner, greener reaction pathways in an effort to reduce volatile organic compounds (VOCs). The first solvents to be discussed (and by far the most fully investigated in the literature) are supercritical fluids. Within this field, supercritical C02 has been the most highly reported solvent. The second solvent class is ionic liquids. These have become increasingly popular over the last five years. Biphasic solvents will then be described and their application to biocatalytic polymerization. This section will be limited to biphasic solvents that are more unusual and, apart from a brief mention, will not encompass the broad field of emulsion polymerization in water. Finally, the use of fluorous solvents will be described. In all cases, the physical properties of the solvent imparts interesting,... 

Polymerization under biphasic conditions offers a number of advantages over conventional solution or bulk polymerization. The ability to easily separate catalyst from reactants or products by way of immobilization in a second, immiscible phase provides a means of rapid and facile purification and separation. Traditional methods of biphasic polymerization include emulsion or suspension-type systems. While these are of huge importance both academically and commercially, they do not fit into the realm of exotic solvents and so will not be described in depth in this section. 

The use of exotic media for biocatalytic polymerization has ranged from the extensive, and often fundamental, studies using supercritical C02, to more exploratory and recent reports for media such as ionic liquids and fhroro-solvents. In all cases, however, intriguing results have lead to further investigation. As increasing pressure is exerted upon scientists in both academia and industry alike to develop and commercialize greener reaction systems, it is expected that biocatalysis and reactions in these and other exotic solvents will continue to be of considerable interest into the future, as they have been over the previous decades. 

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