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Some examples of functional additives include surfactants, emulsifiers, dispersants, adhesion promoters, leveling agents, dyes and pigments, antioxidants, preservatives, and optical brighteners. Practically every type of chemically formulated product is associated with its own formulary of likely functional additive choices that can fulfill ...
Adhesion is the tendency of dissimilar particles or surfaces to cling to one another. (Cohesion refers to the tendency of similar or identical particles and surfaces to cling to one another.) The forces that cause adhesion and cohesion can be divided into several types.
Also, both the adhesion-forming interactions between adhesive and substrate, as well as the inter-intramolecular interactions causing the cohesion, can be adversely affected by external influences (including temperature, humidity, chemicals, radiation, mechanical stress). The degree of impairment depends on the nature of the conditions and ...
The strength of adhesion depends on many factors, including the means by which it occurs. In some cases, an actual chemical bond occurs between adhesive and substrate. Thiolated polymers , for example, form chemical bonds with endogenous proteins such as mucus glycoproteins, integrins or keratins via disulfide bridges. [ 40 ]
There are three major requirements of creating a desirable surface for adhesive bonding of plastics: the weak boundary layer of the given material must be removed or chemically modified to create a strong boundary layer; the surface energy of the adherend should be higher than the surface energy of the adhesive for good wetting; and the surface profile can be improved to provide mechanical ...
Dispersive adhesion, also called adsorptive adhesion, is a mechanism for adhesion which attributes attractive forces between two materials to intermolecular interactions between molecules of each material. This mechanism is widely viewed as the most important of the five mechanisms of adhesion due to its presence in every type of adhesive ...
The reaction is carried out in the presence of a base such as sodium hydroxide, analogous to the formation of bisphenol A-diglycidyl ether. Also aliphatic glycidyl epoxy resins usually have a low viscosity compared to aromatic epoxy resins. They are therefore added to other epoxy resins as reactive diluents or as adhesion promoters. Epoxy ...
Barrier release agents prevent adhesion by the development of a physical film or barrier between the forming surface and the concrete. Reactive release agents are chemically active and work by the process of a chemical reaction between the release agent and the free limes available in fresh concrete. A soapy film is created which prevents adhesion.