Interface Interfacial adhesion

Interfacial adhesion is the adhesion in which interfaces between phases or components are maintained by intermolecular forces, chain entanglements, or both, across the interfaces. Interfacial adhesion between rubber and PMMA must be sufficient to permit the effective transfer of stress to the rubber particles and also to provide multiple sites for crazing and localized shear yielding for effective impact energy dissipation. 

Wear. Ceramics generally exhibit excellent wear properties. Wear is deterrnined by a ceramic s friction and adhesion behavior, and occurs by two mechanisms adhesive wear and abrasive wear (43). Adhesive wear occurs when interfacial adhesion produces a localized Kj when the body on one side of the interface is moved relative to the other. If the strength of either of the materials is lower than the interfacial shear strength, fracture occurs. Lubricants (see Lubricants and lubrication) minimize adhesion between adj acent surfaces by providing an interlayer that shears easily. Abrasive wear occurs when one material is softer than the other. Particles originating in the harder material are introduced into the interface between the two materials and plow into and remove material from the softer material (52). Hard particles from extrinsic sources can also cause abrasive wear, and wear may occur in both of the materials depending on the hardness of the particle. 

In the JKR experiments, a macroscopic spherical cap of a soft, elastic material is in contact with a planar surface. In these experiments, the contact radius is measured as a function of the applied load (a versus P) using an optical microscope, and the interfacial adhesion (W) is determined using Eqs. 11 and 16. In their original work, Johnson et al. [6] measured a versus P between a rubber-rubber interface, and the interface between crosslinked silicone rubber sphere and poly(methyl methacrylate) flat. The apparatus used for these measurements was fairly simple. The contact radius was measured using a simple optical microscope. This type of measurement is particularly suitable for soft elastic materials. 

Creton, C., Kramer, E.J., Hui, C.-Y. and Brown, H.R., Failure mechanisms of polymer interfaces reinforced with block copolymers. Macromolecules, 25, 3075-3088 (1992). Boucher et al., E., Effects of the formation of copolymer on the interfacial adhesion between semicrystalline polymers. Macromolecules, 29, 774-782 (1996). 

Chemical covalent bonding. The formation of covalent chemical bonds between elements at an interface may be an important factor. Such direct chemical bonding would greatly enhance interfacial adhesion, but specific chemical functional groups are required for the reactions to occur. 

Interface trapped charge, in silicon-based semiconductors, 22 240 Interfacial adhesion, in binary... 

Additionally, some properties unique to both systems may result. The majority of homopolymer blends are immiscible with one another and often experience poor interfacial adhesion between the separate phases. Since block copolymers are covalently linked together, macroscopic incompatibility at the interface is minimized. The macroscopic incompatibility of a two-polymer blend may be eliminated by the addition of a block copolymer derived from the two systems. Hence, copolymers can be used to strengthen blends of immiscible polymers by serving as emulsifiers (7-9). 

Most recently, significant research efforts have been focused on materials compatibility and adhesion at the zeoHte/polymer interface of the mixed-matrix membranes in order to achieve enhanced separation property relative to their corresponding polymer membranes. Modification of the surface of the zeolite particles or modification of the polymer chains to improve the interfacial adhesion provide new opportunity for making successful zeolite/polymer mixed-matrix membranes with significantly improved separation performance. 

Schrader, M.E. (1970). Radioisotopic studies of bonding at the interface. J. Adhesion 2, 202-212. Schrader, M.E, and Block, A. (1971). Tracer study of kinetics and mechanism of hydrolytically induced interfacial failure. J. Polym. Sci.. Part C, Polym. Symposia. 34, 281-291. 

The purpose of performing calculations of physical properties parallel to experimental studies is twofold. First, since calculations by necessity involve approximations, the results have to be compared with experimental data in order to test the validity of these approximations. If the comparison turns out to be favourable, the second step in the evaluation of the theoretical data is to make predictions of physical properties that are inaccessible to experimental investigations. This second step can result in new understanding of material properties and make it possible to tune these properties for specific purposes. In the context of this book, theoretical calculations are aimed at understanding of the basic interfacial chemistry of metal-conjugated polymer interfaces. This understanding should be related to structural properties such as stability of the interface and adhesion of the metallic overlayer to the polymer surface. Problems related to the electronic properties of the interface are also addressed. Such properties include, for instance, the formation of localized interfacial states, charge transfer between the metal and the polymer, and electron mobility across the interface. 

The incorporation of SWCNTs induces a remarkable increase in the storage modulus of the matrix at temperatures below the glass transition, which becomes worthless at higher temperatures. The increase in E is more pronounced for the compatibilized samples, attributed to their improved CNT dispersion and interfacial adhesion between the filler and matrix interfaces. 

Yet, for systems A and C, the measured fracture energies remain low compared with the critical fracture energy of the bulk aluminum 10 J Moreover, we do not observe islands of passivation material on the A1 fracture surface and, inversely, we do not observe A1 on debonded surfaces of the passivation films. This suggests that the loss of interfacial adhesion is close to a brittle fracture process despite the influence of plasticity of the A1 substrate and crack blunting at the interface. This sort of brittle mode of interfacial failure, including plastic flow in a ductile material (the substrate), has been observed or discussed for a sapphire/Au interface. ... 

It has been well known that weak interfaces between the inorganic fillers and the organic matrix reduce the mechanical strength of bone cement [38,40,44,45]. The interfacial adhesion strength can be enhanced by plasma treatment, which is generally due to the improved wettability and possibly to the chemical bonds between the filler and the resin [46,47]. Especially in acrylic bone cement, chemical bonds may have an important role in improving the mechanical strength by the plasma treatment. 

Three kinds of adhesion tests were used to evaluate the interfacial adhesion behaviors of these systems the results are summarized in Table 32.3. As is evident from the data, excellent water-insensitive adhesion was obtained for all of the plasma interface-engineered IVD/plasma polymer/E-coat systems examined. 

One of the most important characteristics to consider in choosing a matrix is its adhesion with the fiber. The fiber/matrix interfacial adhesion plays a critical role in the mechanical properties of the composite. The loads are transferred from the matrix to the fiber through the interface, and the strength of the composite depends on the bond between fiber reinforcement and matrix. 

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