Adhesives (Encyclopedia of Science)
Adhesives bond two or more materials at their surfaces. Any time you reattach a handle that has broken off a cup, paste a photograph into an album, or tape a message to a friend's door, you use an adhesive.
Natural adhesives such as beeswax, resin (tree sap), and bitumen (asphalt) have been used since earliest times. Ancient Egyptians used flour paste in the making of papyrus (reed paper) and glue made from animal skin and bones for woodworking. Monks of the Middle Ages (400450) used egg white to glue gold leaf to their illuminated (decorated) manuscripts.
Flour paste, animal glue, and egg white are examples of natural adhesives. Natural adhesives are still widely used but have been replaced for most applications by synthetic adhesives. Synthetic adhesives are compounds invented by chemists with special properties that make them useful for various kinds of bonding. For example, two metals can be bonded to each other using an epoxy resin, a type of plastic. Or metal can be bonded to wood using a rubber like material known as neoprene.
New adhesives and new applications
Researchers are constantly looking for new kinds of adhesives and new ways to use them. For example, engineers at European Airbus, one of the world's largest manufacturers of airplanes, has found that plasticlike adhesives can be used to hold airplane...
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