Search results
Results from the WOW.Com Content Network
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.
Schematic of contact area for the JKR model JKR test with a rigid bead on a deformable planar material: complete cycle. To incorporate the effect of adhesion in Hertzian contact, Johnson, Kendall, and Roberts [5] formulated the JKR theory of adhesive contact using a balance between the stored elastic energy and the loss in surface energy. The ...
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.
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).
In addition to coating the substrates with an adhesion promoter to enable good adhesion, surfaces can also be modified by various methods to prepare them for gluing. The most common surface pre-treatment methods are listed in the adjacent figure. The most important processes for surface pre-treatment (after H. Gleich) [4]
Note 1: Adhesion requires energy that can come from chemical and/or physical linkages, the latter being reversible when enough energy is applied. Note 2: In biology, adhesion reflects the behavior of cells shortly after contact to the surface. Note 3: In surgery, adhesion is used when two tissues fuse unexpectedly. [1]