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Chemical reaction metal adhesion

It can be concluded after all that the results reveal very specific features caused by metal-polymer interactions in the interphase of cured PU on different metal surfaces, though further experimental efforts are needed to gain a more complete understanding of the underlying chemical reactions and adhesion mechanisms. Furthermore, remarkable quantitative differences can be seen in the chemical structure formation of thin PU films with regard to reaction rate and degree of isocyanate consumption. [Pg.86]

Impact tests Such tests reveal the resistance of coatings to deformation and destruction by concentrated sudden stresses. They thus throw considerable light on the integrity of the metal-coating bond. Changes in adhesion through chemical reaction at the paint/metal interface will be reflected in the impact-test values. [Pg.1082]

The chapters in this volume present a concise overview of surface analytical techniques from the specific viewpoint of surface morphology and its modification at the polymer-metal interface. A consistent picture begins to emerge of the chemical reactions occurring on metal deposition and why this leads to metal adhesion. The coeditors hope this information will be timely and useful. [Pg.2]

Gansheimer showed that chemical reactions take place between the sulphur of molybdenum disulphide and metallic surfaces during sliding contact, but established no direct correlation with friction, adhesion or wear life. [Pg.74]

Although all the reactions discussed in this section can contribute to the cross-linking of the adhesive and the chemical bonding of the wood particles, the initial reaction of isocyanate with adsorbed water molecules on the wood surface results in immediate wetting of wood with the formation of polyurea. Even on impervious surfaces like glass or metal, the reaction of isocyanate with adsorbed water results in intimate contact after chemical reaction, including poly-... [Pg.338]

Although the polyurethanes form useful adhesive bonds, particularly between metals and elastomers, their use in the aerospace industry for bonding purposes is limited. Because polyurethanes tend to depolymerize above 120 °C and are subject to hydrolysis, and because aromatic urethanes autoxidize when exposed to thermal or UV light (13). epoxies are the preferred bonding material. Recently they were studied as launch seals for both land and sea missile launch tubes and were found to be superior to seals based on neoprene rubber (14). The chemical reaction for this application is proposed to be that between isocyanates and amines (Reaction 3). [Pg.565]

Another important use for polyisocyanates is in adhesives, usually as additives to rubber cements. For example, in rubber-to-metal adhesion, a chemical bond probably forms between the rubber and metal by reaction of the isocyanate groups with active hydrogens in the rubber and with the hydrated oxide layer on the metal surface. [Pg.984]

To control the extent of chemical reactions between the metallic surface and liquid monomers, leading to the formation of a thick interphase, liquid epoxyamine mixtures were kept in contact with the metallic surface at room temperature for various periods of time before the desired adhesive curing cycle was started (e.g., see Pig. 7.1) at 190 °C, vitrification appeared within a few minutes, stopping any reaction between amine and metal, and/or diffusion phenomenon. These curing cycles allowed the maximum conversion (i.e., the maximum glass transition temperature). Gonversely, when interphase formation was not desired. [Pg.90]

Adhesives (a term generally synonymous with glues, mastics, mucilages, and pastes) produce relatively permanent surface bonds between two substances (paper, glass, wood, metal, etc.) that develop by chemical reaction or as the adhesive cools or dries. The enormous variety of adhesives limits any system of nomenclature, but classification by binder, the major active ingredient, yields the following ... [Pg.1]

In effect, this theory postulates a chemical reaction between promoter, polymer, and mineral substrate as in the chemical bond theory but also suggests that the presence of a region of intermediate modulus between polymer and substrate which transfers stress from the high modulus surface to the relatively low modulus polymer. Adhesive technology has long recognized this principle in specially formulated primers for use when bonding rubbery polymers to metals. [Pg.211]


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See also in sourсe #XX -- [ Pg.61 , Pg.62 ]




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