Phenolics Metallic structures

Phenolic Resins Containing Covalently Bonded, Metallic Structures... 

Polyvinyl acetals Solvent solutions, film, and solids Evaporation of solvent film and solid by heat and pressure Elexible bond modified with phenolics for structural use good resistance to chemicals and oils includes polyvinyl formal and polyvinyl butaryl types Metals, mica, glass, rubber, wood, paper Medium... 

Phenolics or phenol-formaldehyde structural adhesives are chemically reactive systems that cure to form thermosets. In one-component systems, meltable powders (resols) are used as binders for particle board or as alloys (including nitrile-phenolics, vinyl - phenolics, and epoxy-phenolics), which are used in the structural bonding of metals. In two-component systems, the resin and catalyst are mixed and then heated to initiate curing. Both systems cure by a condensation reaction that produces a byproduct. 

The gathering of specific know-how in the aircraft industry started with the transition to metal structures made of aluminum. This step was first made during World War II in the United Kingdom in the light bomber Hornet . In this aircraft some structural aluminum parts were adhesively bonded with newly developed thermosetting phenolic... 

Phenolic-neoprene contact cements are used for structural metal-metal bonding. especially where fatigue resistance and low temperature performance are important [209]. They are also used for bonding textiles, wood, rubbers, plastics, ceramics, and glass to metal and to one another. Solvent toxicity and flammability has greatly reduced the use of contact cements in the wood products industry. Water-based contact cements persist, but generally do not perform as well as the solvent systems, thus allowing market erosion by alternative binders. 

Paints used for protecting the bottoms of ships encounter conditions not met by structural steelwork. The corrosion of steel immersed in sea-water with an ample supply of dissolved oxygen proceeds by an electrochemical mechanism whereby excess hydroxyl ions are formed at the cathodic areas. Consequently, paints for use on steel immersed in sea-water (pH 8-0-8-2) must resist alkaline conditions, i.e. media such as linseed oil which are readily saponified must not be used. In addition, the paint films should have a high electrical resistance to impede the flow of corrosion currents between the metal and the water. Paints used on structural steelwork ashore do not meet these requirements. It should be particularly noted that the well-known structural steel priming paint, i.e. red lead in linseed oil, is not suitable for use on ships bottoms. Conventional protective paints are based on phenolic media, pitches and bitumens, but in recent years high performance paints based on the newer types of non-saponifiable resins such as epoxies. 

Many studies have been undertaken to establish the structural criteria for the activity of polyhydroxy flavonoids in enhancing the stability of fatty acid dispersions, lipids, oils, and LDL. " As for phenolic acids, the inhibition of oxidation by flavonoids is related to the chelation of metal ions via the... 

Amouri, H. Le Bras, J. Taming reactive phenol tautomers and o-quinone methides with transition metals a structure-reactivity relationship. Acc. Chem. Res. 2002, 35, 501-510. 

The first indication that such O-coordinated (phenoxyl)metal complexes are stable and amenable to investigation by spectroscopy was obtained when the electrochemistry of the colorless, diamagnetic complexes [Mm(LBu2)], [Mm(LBuMet)] (M = Ga, Sc) containing three coordinated phenolates in the cis-position relative to each other was investigated in acetonitrile solutions (142). A representative structure of [Scm(LBuMet)] is shown in Fig. 12. 

It has been recognised for centuries that certain natural dyes, including alizarin, kermes, cochineal and fustic, now known to contain o-dihydroxy phenolic or anthraquinonoid residues in their structures, can be fixed on natural fibres using oxides or salts of transition metals as mordants. Although mordanted wool dyed with alizarin showed excellent fastness, reproducibility of shade was difficult to achieve because of the variable composition of the raw materials available. The famous Turkey red, in which alizarin was applied to aluminium-mordanted wool in the presence of calcium salts, formed a metallised complex the nature of which remains in considerable doubt. 

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