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Adhesives commonly react with oxygen at low temperatures, which leads to a slow break down of polymer chains. The breakdown of polymer chains is often undetectable until the adhesive has reached a critical point where the stability of remainder of the adhesive rapidly degrades. [1]
The scrape adhesion test measures the determination of the adhesion of organic coatings when applied to smooth, flat panel surfaces. It is helpful in giving relative ratings for a number of coated panels showing significant differences in adhesion. The tested materials are applied uniformly to flat panels, mainly some sort of sheet metal.
A pull-off test, also called stud pull test, is a type of test in which an adhesive connection is made between a stud and a carrier (or object to be tested) by using a glue, possibly an epoxy or polyester resin, that is stronger than the bond that needs to be tested.
Achieving adhesion between the adhesive and substrate requires not only an adhesive of suitable composition for the substrate, but also places high demands on the substrate surface. Due to the short range of the adhesion forces, the nature of the surface layer of the substrate is crucial.
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.
Adhesives may be broadly divided in two classes: structural and pressure-sensitive. To form a permanent bond, structural adhesives harden via processes such as evaporation of solvent (for example, white glue), reaction with UV radiation (as in dental adhesives), chemical reaction (such as two part epoxy), or cooling (as in hot melt).
For example, ASTM D1000 has test methods for electrical tapes. There are ASTM specifications for many tapes including D2301 for vinyl electrical tape, D5486 for box-sealing tape, etc. Several of the ASTM test methods are coordinated with PSTC, other trade associations, and other international organizations.
The strength of metal oxide adhesion effectively determines the wetting of the metal-oxide interface. The strength of this adhesion is important, for instance, in production of light bulbs and fiber-matrix composites that depend on the optimization of wetting to create metal-ceramic interfaces. [ 1 ]