Kinetics Metal containing polymers

The model considered can be useful for studying the kinetics and mechanism of the formation of metal-containing clusters and nanoparticles in the polymer medium with reactive metal-containing groups. The methodology of... 

Cqpolymerization of MCM with traditional monomers is the main technique of metal insertion into a polymer chain, and it is more widely used than their homopolymerization. However, ocpolymerization laws in such systems are difficult to analyze because of their raultiparameter dependence of the kinetics and copolymerization characteristics on the process, parameters such as pH, solvent nature and even concentration ratio (30). The metal-containing giroup in MCM is, as a rule, an electron-donor substituent (scheme Q-e). The copolymerization yields complexes of different comonomers, effecting the polymer composition and structure. In our view, the most remarkable one is cqpolymerization of transition metal diacrylates with MMA, styrene, etc. (37), as well as vinylpyridine and vinylimidazole MX complexes and formation of ternary copolymers of the following composition (38) ... 

AFCOP) In this technique for making multiphase ceramic matrix composites, an active filler material (a transition metal or compound thereof which will yield a carbide or other ceramic) is mixed with an organometallic polymer and pyrolysed. The kind, content and structure of the filler control the kinetics of the polymer pyrolysis and the resulting microstructure, which may contain disordered or glassy areas. (M. Seibold and P. Greil, 1st European Conf on Adv. Mater Processes.)... 

One method of solving the kinetics dilemma is well known in coordination chemistry that is, start with a labile metal ion and render it inert during the course of the synthetic reaction. We have accomplished this in the case of zirconium(IV) by starting with tetrakis(salicylaldehydo)zirconium(IV), which is quite labile, and polymerization with 1,2,4,5-tetraaminobenzene in a Schiff-base condensation reaction in situ (6). The polymeric product contains a "double-headed" quadridentate ligand, which is much more inert to substitution. However, 1,2,4,5-tetraaminobenzene has become very expensive. Therefore, the synthesis of a zirconium polymer with 3,3, 4,4 -tetraaminobiphenyl (commercially 3,3 -diami nobenzidine) with zirconium salicylaldehyde, Zr(sal)4 (7) has been undertaken as shown below ... 

Hybrid framework compounds, including both metal-organic coordination polymers and systems that contain extended inorganic connectivity (extended inorganic hybrids), have recently developed into an important new class of solid-state materials. We examine the diversity of this complex class of materials, propose a simple but systematic classification, and explore the chemical and geometrical factors that influence their formation. We also discuss the growing evidence that many hybrid frameworks tend to form under thermodynamic rather than kinetic control when the synthesis is carried out under hydrothermal conditions. Finally, we explore the potential applications of hybrid frameworks in areas such as gas separations and storage,... 

Release of the unsaturated chain end of a polyolefin can occur by fi-H transfer to the metal or to a monomer molecule (see Appendix 1 for backgound material). A metal-alkyl species, i.e. the starting unit for a new polymer chain, arises from the metal-hydride species formed in the first case by insertion of an olefin, or it can be formed directly by f-H transfer to a monomer (Figure 20). While the results are thus identical, the two reaction paths differ in their respective kinetics In the first case, the rate-limiting p-H transfer is independent of the olefin concentration, while the rate of p-H transfer to a monomer requires the formation of an olefin-containing reaction complex and will thus increase linearly with olefin concentration. 

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