High-molecular-weight macromolecules

Burch, R. R., Lustig, S. R. and Spinu, M., Synthesis of cyclic oligoesters and their rapid polymerization to high molecular weight, Macromolecules, 33, 5053 (2000). 

From a chemical point of view, the half-life of fluorine-18 allows multi-step synthetic approaches that can be extended over hours. Fluorine-18 has therefore, in spite of its somewhat limited chemical repertoire, been effectively used for the labelling of numerous both relatively simple and complex bioactive chemical structures [3,5-9], including high-molecular-weight macromolecules such as peptides, proteins [10-13] and oligonucleotides [14-18]. General considerations on radiochemistry involving short-lived positron emitters will be discussed in Section 2.3. 

To summarize, Th-FFF is especially well suited for the precise analysis of very high molecular weight macromolecules, macromolecular assemblies or species sub-ject to shear degradation [125], copolymers,polymers prone to surface interaction,... 

Lately many new approaches have been reported which concern supramolecular chemistry concepts with high molecular weight macromolecules. A strong influence on these developments which can only be discussed by a few examples was exerted by the synthesis of cascade type dendrimers already mentioned above [15,23-25]. A typical supramolecular approach in this field is the preparation of metallodendrimers reported by Reinhoudt et al. where the monomer units have been linked by non-... 

Upon ultraviolet irradiation in solution, N,N -nonamethylene-blsdlmethylmaleimide polymerizes into high molecular weight macromolecules with cyclobutane rings in the main chain. The reaction could be sensitized by acetophenone and was quenched by oxygen, ferrocene, and 3,3,4,4-tetramethyl-l,2-diazetine-l,2-dioxide. Stem-Volmer plots were linear for all chromophore concentrations and were dependent on the chromophore concentration. Linear quenching relations can be obtained in the following cases (Scheme IV). 

As implied in the Introduction, both proteins and (deoxy)ribonucleic acids can be viewed as ideal tyligomers—that is, the archetypal biological examples of discrete, high molecular weight macromolecules of mixed sequences with compact solution conformations assembled from many subunits of secondary structure. In our assessment of the literature, we have organized foldamer systems into four... 

However, the presence of only one, two, or three methyl groups per trimer ring in III, IV, and V does not inhibit polymerization . These species polymerize to open-chain, high molecular weight macromolecules when heated at 250°C. 

Interfacial conformational transitions. Once adsorption equilibrium is achieved, replacement of the equilibrium bulk solution with pure solvent (or buffer solution) does not general 1> lead to much desorption, especial Ilf with high molecular weight macromolecules. The interfacial laifer then remains in a metastable state where it is possible to test its structural response to external pertubations such as variations of pH, temperature, ionic strength or ionic composition. However, if the solvent power is significantly increased with respect to adsorption conditions, significant desorption may occur, and the thickness veiriations then reflect variations of both molecular interfacial dimensions and concentration. 

Kawaguchi, D., Masuoka, K., Takano, A., Tanaka, K., Nagamura, T., Torikai, N., et al. Comparison of interdiffusion behavior between cyclic and linear polystyrenes with high molecular weights. Macromolecules 39, 5180-5182 (2006)... 

Layec-Raphalen, M.N. Wolff, C. Shear rate dependence of the association of high molecular weight macromolecules in dilute solution. Rheology, Vol. 2, 303-, Ed. G. Astarita et al., Plenum Press, 1980... 

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