Organometallic stabilizers

Acetyl ligands, in niobium complexes, C-H BDEs, 1, 298 Achiral phosphines, on polymer-supported peptides, 12, 698 Acid halides, indium compound reactions, 9, 683 Acidity, one-electron oxidized metal hydrides, 1, 294 Acid leaching, in organometallic stability studies, 12, 612 Acid-platinum rf-monoalkynes, interactions, 8, 641 Acrylate, polymerization with aluminum catalysts, 3, 280 Acrylic monomers, lanthanide-catalyzed polymerization,... 

Biological alkylation, organometallics stability, 12, 607 Biological effects, Ti(IV) complexes, 4, 662 Biologically active substances, via enyne metathesis, 11, 295 Biologically relevant compounds, via Alder-ene reactions,... 

Cannula transfers, in anaerobic experimentation, 1, 205 Capillary electrophoresis, for organometallics stability studies, 12, 621... 

High-performance liquid chromatography in organometallics stability analysis, 12, 617 tin environmental studies, 12, 635 High polymers oligosilanes as models, 3, 552 polysilanes... 

The large group of inhibitors of free radical chain reactions are frequently used in combination with metal salts or organometallic stabilizers. They are amines, sulfur- or phosphorus-containing compounds, phenols, alcohols, or chelates. Aromatic phosphites at about 1 p.p.r. chelate have undesirable metal impurities and inhibit oxidative free radical reactions. Some of the more popular are pentaerythritol, sorbitol, melamine, dicyan-diamide, and benzoguanamine. Their synergistic effect is utilized in vinyl floors where low cost is imperative. 

It is not the purpose of this paper to review or expound on the well-documented stabilization mechanisms for PVC. Nor will we consider the other well known auxiliaries to PVC stabilization such as phosphites, epoxies, and hindered phenols. Rather, attention will be paid to only the primary metallic and organometallic stabilizers, the principle elements illustrated in Table I. The metal soap derivatives of the Group... 

Table I. Elements of Metallic (or Organometallic) Stabilizers of Interest in Stabilizing Poly (vinyl chloride)...

Among the organometallic stabilizers, compounds of quadrivalent tin are most widespread. Monomer organotin compoimds most often have the general formula... 

There are several additives such as organometallic stabilizers, which are incorporated in plastics for reasons unconnected with microbial action, but which nevertheless actually help to promote resistance. Some of the additives which provide incidental resistance to biological action are used in resins which do not require any protection. Others are inadequate because of lack of stability during processing and/or... 

Other techniques that have been used for the examination of organometallic stabilizers extracted from PVC include colunm chromatography (barium, cadmium and zinc salts of fatty acids ), paper chromatography (cadmium, lead and zinc salts of fatty acids) and polarography (cadmium, lead and zinc salts) . ... 

The mechanism of action of these organometallic stabilizers may be plausibly connected with their ability to quench, even if only partially, the excited singlet and triplet states of the carbonyl groups that are present at random in the polymer chain. This mechanism is supported by numerous experimental data mostly obtained for liquid phase systems. 

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