Adhesive entrapment mechanism

A soil particle impinging on a fabric is captured or bounces off the fabric surface. The capture of the particle can occur by adhesion or entrapment mechanisms. Scanning electron micrographs indicate that soil particles on a fabric that has been vacuum cleaned adhere to the fiber surface and are distributed over the fiber surface. Kling and Mahl [17], Powe [18], and Kissa [19] have shown that the main cause of soiling is adhesion, not entrapment of soil. Kissa [19] has demonstrated that particulate soil can adhere to initially smooth surfaces, such as polyester or polyethylene film. The impingement of soil particles can, however, deform the film surface and increase the contact area. 

Fig. 8. Bubble-particle mechanisms in DAF (A) particle-bubble collision and adhesion (B) bubble formation at particle surface (C) microbubble entrapment in aggregates (D) bubbles entrainment by aggregates. [Adapted from Rubio et al. (24).]...

Some hybrid materials have already entered the market. Commercial examples include materials from electronics to automotive coatings with varied mechanical and optical properties, adhesives, and composites, to cite a few. " Recent examples include the indigo dyes embedded in a silica/zirconia matrix (Toshiba TV screens), organically doped sol-gel glassware (Spiegelau), and sol-gel entrapped enzymes (Fluka). 

Various other equations have been proposed that attempt to combine the properties of components in such a way that the properties of the resulting composites can be predicted [5]. In real systems, however, complications arise from the size, shape, orientation and state of adhesion between the fillCT and the matrix [5], Real systems also suffer from imperfect dispersion of the fiUer within the matrix, and the entrapment of air in the composite during the mixing process. Both have profound effects on the mechanical properties of the resulting composite. Nonetheless, the principle remains that composite materials are used because they have improved properties compared to those of the polymer phase alone. 

There is a basic difference between the bonded inserts, which rely solely on adhesion for their attachment to the parent component, and the embedded inserts, where the attachment to the composite member is based on mechanical interlocking or entrapment, although the latter are often secured by bonding for convenience. 

There are numerous examples of the application of fracture mechanics to structural adhesive systems. Most notable are those of Mostovoy and his coworkers which have already been mentioned. " Bascom and coworkers have made significant contributions to the understanding of the effect of bondline thickness on fracture toughness. Kinloch and Shaw extend the work of Bascom to include rate effects and to develop mathematical models of the fracture resistance of adhesives. Hunston et al have used these methods to study viscoelastic behavior in the fracture process of structural adhesives.Mostovoy and Ripling used these techniques to determine the flaw tolerance of several adhesives,while Bascom and Cottington have studied the effect of flaws caused by air entrapment in structural adhesives." Finally it must be mentioned that one of the most simple, most widely used tests for strucural adhesives, the peel test, is actually a version of the double cantilever beam test. 

Malfunction of a PD catheter can have many sources. Catheters can have mechanical failure, for example develop holes, cracks and/or leaks. Catheters can develop occlusions due to anatomic reasons such as ingrowth of omentum, malposition, or entrapment in adhesions. In addition, constipation is known to be related to poor catheter function. A careM history and evaluation of a PD catheter will often identify the most likely cause of loss of catheter function and assist the physicians in developing a plan for restoring function. 

The thermal stability of polystyrene composites reinforced with short sisal fibres was found to be better than that of sisal fibre and the PS matrix [a.288]. The effects of fibre loading, length, orientation and modification on the dynamic mechanical properties of the composites were evaluated. Benzoylation, maleic anhydride coating of the polystyrene and acetylation of the fibres were fibre modifications and treatments that were carried out to improve fibre/matrix adhesion through specific interactions of the macrochains. The Tg values of the composites were lower than that of unreinforced PS, and this effect was attributed to the presence of some residual solvent in the composites entrapped during composite preparation. However, the composites with treated fibres showed better thermal degradation properties than those with untreated fibres. 

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