Reinforcing elastomers

Pinch The industrial equivalent of controlling flow bv pinching a soda straw is the pinch valve, Mves of this tvpe use fabric-reinforced elastomer sleeves that completely isolate the process fluid from the metal parts in the valve. The valve is actuated bv applying air pressure directly to the outside of the sleeve, causing it to contract or pinch. Another method is to pinch the sleeve with a linear actuator with a specially attached foot. Pinch valves are used extensively for corrosive material service and erosive sliirrv senice. This type of valve is used in applications with pressure drops up to 10 bar (145 psi),... 

It is an apparent consequence of the second role that SBS polymers with a molecular mass of about 80 000 behave like carbon-black-reinforced elastomers as illustrated in Table 11.16 in respect of tensile strength. 

Isham, A.B., Glass Fiber-Reinforced Elastomers for Automotive Applications—A Comparison of RIM Urethanes and Alternate Material Systems, Soc. Autom. Engl Meet., Preprint No. 760333, Feb. 1976. 

Reinforced Elastomers From Molecular Physics to Industrial Applications... 

Before dealing with reinforcement of elastomers we have to introduce the basic molecular features of mbber elasticity. Then, we introduce—step-by-step—additional components into the model which consider the influence of reinforcing disordered solid fillers like carbon black or silica within a rabbery matrix. At this point, we will pay special attention to the incorporation of several additional kinds of complex interactions which then come into play polymer-filler and filler-filler interactions. We demonstrate how a model of reinforced elastomers in its present state allows a thorough description of the large-strain materials behavior of reinforced mbbers in several fields of technical applications. In this way we present a thoroughgoing line from molecular mechanisms to industrial applications of reinforced elastomers. 

FE simulations of the stress-strain properties of fiUer-reinforced elastomers are an important tool for predicting the service live performance of mbber goods. Typical examples are the evaluation of rolling resistance of tires due to hysteresis energy losses, mainly in the tire tread or the adjustment of engine mounts in automotive applications. 

Non-spherical filler particles are also of considerable interest [50,69]. Prolate (needle-shaped) particles can be thought of as a bridge between the roughly spherical particles used to reinforce elastomers and the long fibers frequently... 

Uniaxial deformations give prolate (needle-shaped) ellipsoids, and biaxial deformations give oblate (disc-shaped) ellipsoids [220,221], Prolate particles can be thought of as a conceptual bridge between the roughly spherical particles used to reinforce elastomers and the long fibers frequently used for this purpose in thermoplastics and thermosets. Similarly, oblate particles can be considered as analogues of the much-studied clay platelets used to reinforce a variety of materials [70-73], but with dimensions that are controllable. In the case of non-spherical particles, their orientations are also of considerable importance. One interest here is the anisotropic reinforcements such particles provide, and there have been simulations to better understand the mechanical properties of such composites [86,222],... 

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