Other Factors Affecting Adhesion

In the ideal situation, a treated textile would immediately be incorporated into the polymer matrix and the final product cured immediately. In practice this is rarely, if ever the case, and therefore the treated textile must be stored (and often transported) before it is incorporated into the polymer. 

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Other Factors Affecting Adhesion of Rubber to Brass Coated Steel Wire... 

Several other factors affect the frictional forces. If one or both of the contacting surfaces have a relatively low compression modulus it is possible to make intimate contact between the surfaces which will lead to high friction forces in the case of plastics having good adhesion. It can add to the friction forces in another way. The displacement of material in front of the moving object adds a mechanical element to the friction forces. 

Other factors affecting the life of an adhesive bond are humidity, water immersion, and outdoor weathering. Moisture can affect adhesive strength in two ways. Some polymeric materials, notably ester-based pol)nirethanes, will revert, i.e., lose hardness, strength, and in the worst case, turn to fluid during exposure to warm humid air. Water can also permeate the adhesive and displace the adhesive at the bond interface. Structural adhesives not susceptible to the reversion phenomenon are also likely to lose adhesive strength when exposed to moisture. 

To demonstrate the T-stress effect and to understand other factors affecting crack path selection, the authors and their coworkers [13,25,31,32] carried out a series of experimental studies with adhesively bonded joints to determine the effects of T-stress, specimen geometry, external loading conditions, surface pretreatment. 

In addition to tip shape considerations, other factors affect the applicability of this method. Some of these factors are adhesion hysteresis, interfadal adhesive energy between the tip and the sample, the relative stiffness of the cantilever and the sample, and environmental humidity. Since tins model to evaluate elasticity of a sample is based on the tip-sample adhesion behavior, the adhesion between the cantilever and the sample should be enough to deform the cantilever and the sample measurably as the tip is pulled away from the sample surface, yet not be so much that the induced cantilever deflection is over the detection limit of the AFM. The capillary effect, which results from the condensation of water around the tip on hydrophilic surfaces, can be important in determining the tip-sample behavior.However, its effert in hydrophobic polymers such as PDMS is minimal. 

This strnctnring of liqnids into discrete layers when confined by a solid surface has been more readily observable in liquid systems other than water [1,55]. In fact, such solvation forces in water, also known as hydration forces, have been notoriously difficult to measure due to the small size of the water molecule and the ease with which trace amounts of contamination can affect the ordering. However, hydration forces are thought to be influential in many adhesive processes. In colloidal and biological systems, the idea that the hydration layer mnst be overcome before two molecules, colloidal particles, or membranes can adhere to each other is prevalent. This implies that factors affecting the water structure, such as the presence of salts, can also control adhesive processes. 

A freshly cleaned tooth surface quickly becomes coated with a thin pellicle of salivary proteins. This provides a surface for growth of dental plaque, which contains many bacteria and adhesive polysaccharides such as dextrans.1 The latter are generated from dietary sucrose by such bacteria as Streptococcus mutans. (Chapter 20) and others.131 Many factors affect the probability of tooth decay. 

LDPE coating to polyester film, clay-coated liner board, and aluminum foil was improved by an addition of calcium carbonate. Adhesion increases as the amount of calcium carbonate is increased and at a 30% level it is doubled. The adhesion of SBR to a polyurethane adhesive was substantially improved (400%) by the addition of silica but only when the surface was roughened. The amount of silica did not affect adhesion of unroughened SBR. The use of MgO with silane coupling increased adhesion of bromobutyl liner by a factor of four. Generally, in the reported data, surface roughening of the filled composite contributes to a better adhesion to other substrates joined by adhesives. 

Other factors. The long-term adhesion of the coating is affected by the properties of the polymer such as stiffness or rigidity, dimensional stability, and coefficient of expansion. The physical properties of the paint film must accommodate to those of the polymer. 

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