Adhesive bond, permanent

J. D. Minford, Aluminum Adhesive Bond Permanence, in Treatise on Adhesion and Adhesives. Vol. 5 (R. L. Patrick, ed.), Marcel Dekker, New York, 1981. 

Polyelectrolytes form the basis of those modern cements which are distinguished by their ability to adhere to reactive surfaces. At present the main use of such cements lies in the medical field, principally in dental surgery. They adhere permanently to biological surfaces where they have to withstand adverse conditions of wetness, chemical attack, the stress of biological activity, and chemical and biological changes within the substrate. Nevertheless, adhesive bonds are maintained. 

There are many obstacles to permanent adhesion under oral conditions. The substrate is a biological tissue and subject to change, and the presence of moisture represents the worst kind of situation for adhesion. Water is the great barrier to adhesion. It competes for the polar surface of tooth material against any potential polymer adhesive. It also tends to hydrolyse any adhesive bond formed. These twin obstacles gave rise to considerable doubt as to whether materials adhesive to tooth material could be developed at all (Cornell, 1961). 

The bond strength to enamel (2-6 to 9-9 MPa) is greater than that to dentine (1-5 to 4-5 MPa) (Wilson McLean, 1988). Bond strength develops rapidly and is complete within 15 minutes according to van Zeghbroeck (1989). The cement must penetrate the acquired pellicle (a thin mucous deposit adherent to all surfaces of the tooth) and also bond to debris of calciferous tooth and the smear layer present after drilling. Whatever the exact mode of bonding to tooth stmcture, the adhesion is permanent. The principles and mechanism of adhesion have already been discussed in Section 5.2. 

These properties have a profound effect on the processing properties of the uncured adhesive and on the end properties of the fully cured product. The properties determined by physical chemistry affect both the cohesive strength of the adhesive film as well as the degree of adhesion to the substrate. They also affect the permanence and durability of the adhesive bond once it is placed into service. 

Effect of Bacteria Contamination on Permanence of Adhesive Preparations and Adhesive Bonds D1174... 

Effect of Mold Contamination on Permanence of Adhesive Preparation and Adhesive Bonds, Test for D 1286... 

Sharpe, L. H., Aspects of the Permanence of Adhesive Joints, in Structural Adhesive Bonding, M. J. Bodnar, ed., Interscience, New York, 1966. 

Minford, J. D., in Permanence of Adhesive Bonded Joints, Durability of Structural Adhesives, A. J. Kinloch, ed., Applied Science Publishers, London, 1983, p. 135. 

Environmental Tests. It is desirable to know the rate at which an adhesive bond will lose strength due to environmental factors in service. Strength values determined by short-term tests do not give an adequate indication of an adhesive s performance during continuous environmental exposure. Laboratory-controlled aging tests seldom last longer than a few thousand hours. To predict the permanence of an adhesive over a 20-year product life requires accelerated test procedures and extrapolation of data. Such extrapolations are extremely risky because the causes of adhesive bond deterioration are complex (see Sec. 15.2.2). Unfortunately no universal method has yet been established to estimate bond life accurately from short-term aging data. 

Miniford, J. D., Permanence of Adhesive-Bonded Aluminum Joints, Chapter 23 in Adhesives in Manufacturing, G. L. Schneberger, ed., Marcel Dekker, New York, 1983. 

Miniford, Permanence of Adhesive-Bonded Aluminum Joints. ... 

This first critical phase may initiate the most permanent alteration of the artifact s tissue, as its field often involves the microstructure of the wood cell. Attachment through adhesive bonding tends to engage the most widespread interaction with the intrinsic tissue. Mechanical interlocking devices, such as threaded rods and pins held in place by friction, function by crushing the substrate to increase its solidity. 

An adhesive is a material that is applied to the surfaces of articles to join them permanently by an adhesive bonding process. An adhesive is a substance capable of forming bonds to each of the two parts when the final object consists of two sections that are bonded together. A feature of adhesives is the relatively small quantities that are required compared to the weight of the final objects. 

Solvent solutions and latex cements require the removal of the solvent from the adhesive before bonding can take place. This is accomplished by simple or heat-assisted evaporation. Some of the stronger or more environmentally resistant rubber-based adhesives require an elevated-temperature cure. Only slight pressure is usually required with pressure-sensitive adhesives (PSAs) to obtain a satisfactory bond. These adhesives are permanently tacky and flow under pressure, thus they provide intimate contact with the adherend surface. 

ASTM D1877-77 (withdrawn 1984) Standard Test Method for Permanence of Adhesive-Bonded Joints in Plywood Under Mold Conditions... 

ASTM D1581-60 (1984) (withdrawn 1991) Standard test method for bonding permanency of water-or solvent-soluble liquid adhesives for labeling glass bottles. 

Permanence—The resistance of an adhesive bond to deteriorating influences. 

Adhesive bonding is also usefiil for the repair of both metals and composites patches can be applied as temporary or permanent repairs to reinforce damaged stractures and bonded in place using special equipment to apply heat and pressure (see Repair methods). In these circumstances, it is not always possible to use the same pre-treatment and bonding... 

Bonding Permanency of Waters or Solvent-Soluble Liquid Adhesives for Labeling Glass Bottles, Tbst for (D 1581)... 

Bonding Permanency ofWater- or Solvent-Soluble Liquid Adhesives for Automatic Machine Sealing Top Flaps of Fiber Specimens, Test for (D 1713)... 

Susceptibility of Dry Adhesive Film to Atta by Roaches, Test for (D1382) Susceptibility of Dry Adhesive Film to Attack by Laboratory Rats, Teat for (D 1383) Permanence of Adhesive-Bonded Joints in Plywood under Mold Conditions, Test for (D... 

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