Mechanisms of reinforcement

Einstein developed the concept of hydrodynamic reinforcement which is expressed by the equation  

This simple model was later extended by Guth and Gold to include interparticular disturbances. One form of this model is given by Eq 7.6. This model modified by Thomas fits some experimental data  

Model previously developed by Kraushas got additional interpretation in recent works. Kraus gave simple equation  

On surface it is very simple model but effective concentration of filler includes observation that some layer of polymer is bound to the surface of filler and the mechanisms of this bonding is mathematically expressed by effectiveness factor. The recent model assumes that filler particles are spheres which might be connected to form chain-like agglomerates. Each particle is surface coated with matrix polymer. The elastomeric layer is considered immobilized. The effective filler volume is higher than filler volume fraction by the amount of adsorbed polymer. The effectiveness factors is given by equation  

Several performance characteristics of rubber such as abrasion resistance, pendulum rebound, Mooney viscosity, modulus, Taber die swell, and rheological properties can be modeled by Eq 7.34. A complex mathematical model, called links-nodes-blobs was also developed and experimentally tested to express the properties of a filled rubber network system. Blobs are the filler aggregates, nodes are crosslinks and links are interconnecting chains. The model not only allows for 

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More detailed discussion on the interface of fiber length is given in Section X, Theory and Mechanics of Reinforcement. 

Figure 3.4 Mechanism of reinforcement by rubber particles in a glassy polymer matrix...

I As will be explained in the next chapter, actual outcomes can also maintain or eliminate behavior through the mechanism of reinforcement. 

This argument, combined with that of chapter IV, suggests that optimal adaptation will be an exception rather than the rule. In general, neither subjective nor objective mechanisms can be trusted to make people do what it is in their interest to do. Rational choice is often indeterminate and cannot be counted on to yield optimal behavior, even assuming that people get rid of their tendencies to behave irrationally. Selection processes work too slowly to produce behavior that is optimally adapted to a rapidly changing environment. The next chapter suggests that the mechanism of reinforcement is no more likely to force optimal behavior. 

The substrate/silane interphase and the silane/matrix interphase are equally important in considering the mechanism of reinforcement by silane coupling agents in composites. The mineral oxide/silane interphase is more well defined than a metal/silane or a silane/matrix interphase. For example, in the case of a metal substrate, surface oxides may dissolve into the silane layer or form a complex. In the case of the silane/matrix interphase, a diffuse boundary layer may exist due to dispersion of physisorbed silanes in the matrix phase or penetration of the matrix resin into chemisorbed silane layers. Many features of the interaction of a silane coupling agent with a polymer matrix are specific to the system, and thus the chemistry of the silane/matrix interphase must be characterized and defined for each system. 

Lee (41, 42) offers a valuable contribution on the mechanism of reinforcement and especially on the role of adhesion and wetting in elastomeric adhesives, pressure-sensitive tapes, nonpigmented organic coatings, and composites such as resin-reinforced rubbers or thermoplastics. I am sure it will generate much discussion. Lee (43) presents a... 

Mechanisms of Reinforcement. Both rubber reinforced with a filler (49, 50) and thermoplastics reinforced with a rubber (29, 55) have been reviewed especially with respect to the mechanism of reinforcement. According to Nielsen (50), Kerner s equation (28) is appropriate to describe the moduli of both of these systems provided perfect adhesion exists at the interfaces ... 

While due to their well-known plastic deformation properties glassy polymers provide excellent model systems for fracture studies, most engineering plastics are semicrystalline. Nevertheless, the molecular mechanisms of reinforcement of interfaces between semicrystalline polymers are much less well understood and the first systematic studies on the subject have only appeared recently [16, 30,96-99]. The reasons for this are mainly twofold ... 

From the main results presented in the preceding paragraphs two separate mechanisms of reinforcement of the interface can be distinguished ... 

Here, a distinction is made regarding the permanence of filler chain bonds. This subject has evolved throughout this chapter and it is an important factor in understanding the mechanism of reinforcement. 

These models address specific cases related to work done on experimental materials. A broad discussion of the mechanisms of reinforcement can be found in the specialized monograph by one of the experts in the field.There has been a concerted effort to analyze materials in many different ways and we have tried to present much of this work in this chapter. Many successful attempts have been made to develop universal relationships which explain the reasons for reinforcement and material behavior under external stresses. 

Tensile properties of composite propellants depend on the tensile properties of the matrix, concentration of the components, particle size, particle-size distribution, particle shape, quality of the interface between fillers and polymeric binder, and, obviously, experimental conditions (strain rate, temperature, and environmental pressure). Many authors (2, 3) have explained the effect of fillers on the mechanical properties of composites, the importance of the filler-matrix interface on physical properties, and the mechanism of reinforcement of the material. Other efforts have examined the effect of experimental conditions on the failure properties of filled elastomers. Landel and... 

Unsatisfactory as the experimental evidence is, it is nevertheless the writers opinion that these results demonstrate that, whatever the mechanism of reinforcement may be, it cannot involve rigid, immovable bonds to the filler material. 

During fabrication, the LCP forms fine fibrils that reinforce the thermoplastic polymer matrix. The mechanism of reinforcement resemble those of glass fibers. However, when light weight is a key issue, in situ composites are superior in comparison to glass fibers. ... 

Wang, WJ. Feng, T. 2005. Study on mechanism of reinforcing sides to control floor heave of extraction opening. Chinese journal of rock mechanics and engineering24(5) %0 - 11. 

Cansell, F. Aymonier, C. Loppinet-Serani, A. (2003) Review on Materials Science and Supercritical Fluids. Curr. Opin. Solid State Mater. Sci. Vol.7, No.4-5, pp.331-340 Chang, t. Jensen, L. Kisliuk, A. Pipes, R. Pyrz, R. Sokolov, A. (2005) Microscopic mechanism of reinforcement in single-wall carbon nanotube / polypropylene nanocomposites. Polym. Vol.46, No. 2,pp.439-444 Coleman, J. Cadek, M Blake, R. Nicolosi, V. Ryan, K Belton, C. Fonseca, A. Nagy, J. Gim ko, Y. Blau, W. (2004) High Performance Nanotube-Reinforced Plastics ... 

Grellmann, W., Heinrich, G., Kaliske, M., Kliippel, M., Schneider, K., VUgis, T. (Eds.) Fracture Mechanics and Statistical Mechanics of Reinforced Elastomeric Blends Springer-Verlag Berlin Heidelberg 2013 ISBN Hardcover 978-3-642-37909-3 and ISBN E-Book 978-3-642-37910-9 http // www.springer.com/materials/mechanics/book/978-3-642-37909-3... 

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