Adhesion mechanisms direct-chemical bonding

There is very good agreement between the 0q values obtained directly from the mechanical debonding experiments and the calculated values obtained by surface chemical methods. This represents a powerful vindication of the GFM theory of adhesion, since for interfaces bonded only by secondary interatomic bonds 0q and are, by definition, the same quantity, namely, the energy required per unit area to break the interfacial atomic bonds. 

Elastomer adhesion mechanisms are discussed first from the viewpoint of vulcanization bonding to metals. The approaches of brass plate bonding, bonding with ebonite, with butadiene-methacrylic acid copolymers, and with proprietary adhesives are cursorily reviewed to invoke theories of chemisorption, diffusion, and directed chemical reaction. The time dependency of peel strength as an adhesion response through the vulcanization cycle is cited as a possible indication of mechanism. 

Nonwoven geotextiles. Nonwoven fabrics are defined as a sheet, web, or batt of directionally or randomly oriented fibres/filaments, bonded either by friction, and/or cohesion, and/or adhesion. In general, nonwoven fabric formation can be considered as a two-step process web formation (aligning the fibres with certain orientation characteristics) and bonding these fibres by mechanical, thermal, or chemical means. This two-step process has formed the classification of nonwoven structures, i.e. carded, airlaid, spunlaid, meltblown, needlepunched, hydroentangled, adhesive bonded, thermal bonded, stitch bonded, etc. Some of the important processes that are used for the manufacture of nonwoven geotextiles are discussed below. 

The excellent stability of ceramics under extreme chemical and thermal enviromnents is often the primary reason for their selection. However, the ceramic component must be joined to the rest of the device. There are many joining techniques that can be utilized, these range from mechanical attachment to direct bonding methods such as brazing or adhesive bonding. With all these methods, the correct design criteria for ceramic materials must be followed. These criteria must address issues such as... 

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