Effect Of Interfacial Bonding On The Strength Of Adhesion Between Elastomer Layers
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Effect of Interfacial Bonding on the Strength of Adhesion of Elastomers, I. Self-Adhesion
| Author | : R. -J. Chang |
| Publisher | : |
| Total Pages | : 51 |
| Release | : 1981 |
| Genre | : |
| ISBN | : |
Two partially-gelled (crosslinked) layers of elastomer were pressed into intimate contact and the gelation reaction was then taken to completion. By varying the extent of initial gelation, the degree of chemical interlinking was varied from zero, when two fully-reacted sheets were pressed together, up to a level characteristic of the final density of molecular linking within each layer, when they were brought together before any reaction had occurred. The strength of adhesion between the layers was measured under threshold conditions, i.e., at low rates of peel, at high temperatures, and, in some instances, with the layers swollen with a compatible liquid. Linear relations were obtained between the threshold work of detachment per unit of interfacial area and the amount of chemical interlinking, deduced from the kinetics of molecular linking within each layer. At any degree of interlinking, ranging from zero to the fully interlinked state, the work of detachment was lower for networks composed of shorter molecular chains, in accordance with the Lake-Thomas theory of the threshold strength of elastomer networks. By extrapolation to the fully-interlinked state, the strength of adhesion corresponding to cohesive rupture was inferred. These values agreed with measured tear strengths for polybutadiene gelled by a free-radical process. For a sulfur crosslinking system, and for both free-radical and sulfur crosslinking of poly(ethylene-co-propylene), the threshold tear strength of the elastomer was found to be much higher than the extrapolated value from adhesion measurements.
Effect of Interfacial Bonding on the Strength of Adhesion of Elastomers II. Dissimilar Adherends
| Author | : R. -J. Chang |
| Publisher | : |
| Total Pages | : 24 |
| Release | : 1981 |
| Genre | : |
| ISBN | : |
Two elastomer layers, differing either in initial degree of crosslinking or in chemical reactivity, were bonded together by a free-radical crosslinking process. The elastomers employed were polybutadiene (BR) and an ethylene-propylene copolymer (EPR), differing in the efficiency of crosslinking by dicumyl peroxide by a factor of about 20. When a fully-crosslinked sheet of either elastomer was pressed into contact with a partially-crosslinked sheet of the same elastomer and the crosslinking then taken to completion, the strength of adhesion under threshold conditions was found to be qualitatively in accord with the predictions of a simple theoretical treatment for the degree of interlinking in terms of the corresponding homogeneous crosslinking reaction. Whereas the theory suggests that the effective degree of interlinking will be one-half of that generated in a homogeneous system, the experimental results were in accord with a figure of about 70 per cent. When a layer of one elastomer was bonded to a layer of the other in a similar way, the strength of adhesion was found to be relatively high when the initial fully-crosslinked layer was BR and relatively low when it was EPR. These results were also in qualitative agreement with theoretical predictions for the degree of chemical interlinking developed between layers differing in chemical reactivity. Thus a general correlation appears to hold between the threshold strength of adhesion and the amount of interlinking. (Author).
Effect of Interfacial Bonding on the Strength of Adhesion of Elastomers. III. Interlinking by Molecular Entanglements
| Author | : A. N. Gent |
| Publisher | : |
| Total Pages | : 28 |
| Release | : 1984 |
| Genre | : |
| ISBN | : |
Polydimethylsiloxane (PDMS) networks have been formed by endlinking linear PDMS molecules. When second layer is cast on top of a fully-gelled lower-layer, the new molecules diffuse into the surface of the lower layer and form molecular loops ('entanglements') in the course of endlinking with themselves. The two layers are then joined only by the macromolecular loops. Measurements have been made of the work required to separate such layers under threshold conditions, i.e., at low rates, high temperatures, and, in some cases, in the swollen state. Values of the work of detachment have been found to be generally about one-half of the work of fracture of the layers themselves, and consistent with the inferred density of interlinking molecular loops at the interface. The values were higher for higher densities, roughly in proportion, and for interlinking molecular strands of higher molecular weight, in accordance with the theory of Lake and Thomas. In the absence of interlinking the work of detachment was extremely small.
Effect of Interfacial Chemical Bonding on the Strength of Adhesion of Glass- Polybutadiene Joints
| Author | : P. Dreyfuss |
| Publisher | : |
| Total Pages | : 18 |
| Release | : 1977 |
| Genre | : |
| ISBN | : |
Strong positive effects of interfacial chemical bonding on the adhesion of an elastomer layer to a glass substrate are reported. Treatment of glass slides with p-bromomethylphenylpoly-siloxane led to strong adhesion with dicarboxyterminated poly-butadiene, whereas treatment with p-tolylpolysiloxane led to weak adhesion. SEM studies confirmed the presence of adhering elastomer in the former case and not in the latter. Swelling stresses were found to discriminate between relatively strongly-bonded systems of the former type, causing earlier bond failure for less firmly bonded elastomer layers. (Author).
Modeling and Simulation Based Life-Cycle Engineering
| Author | : Ken Chong |
| Publisher | : CRC Press |
| Total Pages | : 359 |
| Release | : 2004-02-03 |
| Genre | : Architecture |
| ISBN | : 1482264714 |
Advances in computational power have facilitated the development of simulations unprecedented in their computational size, scope of technical issues, spatial and temporal resolution, complexity and comprehensiveness. As a result, complex structures from airplanes to bridges can be almost completely based on model-based simulations. This book gives
Rubber to Rubber Adhesion
| Author | : Dinesh Kumar Kotnees |
| Publisher | : John Wiley & Sons |
| Total Pages | : 452 |
| Release | : 2021-08-11 |
| Genre | : Technology & Engineering |
| ISBN | : 1119769337 |
In diesem Buch werden die verschiedenen Aspekte der Gummi-Gummi-Haftung betrachtet. Gummi ist ein Polymer mit einer Glasübergangstemperatur deutlich unterhalb der Raumtemperatur, daher sind die Ketten bei Raumtemperatur und höheren Temperaturen äußerst mobil. Diese Eigenschaft macht das Material sehr vielseitig. Gummi wird in zahlreichen Anwendungen eingesetzt, vom Bergbau über Fahrzeugreifen bis zum Space-Shuttle. In all diesen Fällen werden Gummimischungen in Verbundstoffen verwendet und zusammengefügt. Je höher die Haftung, desto höher ist auch die Verbindungsfestigkeit. Die Grundsätze der Adhäsionswissenschaft und -technik werden umfassend genutzt, um bessere Verbindungen und somit nützlichere Produkte herzustellen. Der Inhalt dieses Werks ist nicht nur von theoretischer Bedeutung, sondern hat auch Auswirkungen auf die Praxis. Die Gummi-Gummi-Haftung ist ein allgegenwärtiges Thema. Daher ist das Buch ein wichtiges Hilfsmittel für Wissenschaftler, Mitarbeitende in der Forschung und Entwicklung, Beschäftigte in Unternehmen sowie Personen, die sich in der Praxis mit Gummi und Haftung beschäftigen. Das Buch findet in den unterschiedlichsten Fachgebieten Verwendung (Polymere, Materialwissenschaft, Verfahrenstechnik, Chemie usw.). Zunächst wird das Material Gummi vorgestellt, es folgt eine Charakterisierung von Gummi, Angaben zu Gummioberflächen und -verbindungen und schließlich befassen sich die weiteren Kapitel mit der Gummi-Gummi-Haftung. Die wissenschaftlichen Aspekte, die zum Verständnis der Technik erforderlich sind, werden hervorgehoben. Das Werk enthält eine ausführliche Darstellung der Haftung zwischen unvulkanisierten Elastomeren, der Selbstheilung von Elastomeren, der Haftung zwischen Elastomermischungen durch Co-Vernetzung, der Haftung zwischen teilvulkanisierten Gummimischungen und teilvulkanisierten Gummimischungen, der Haftung zwischen vulkanisiertem Gummi und unvulkanisiertem Gummi oder teilvulkanisiertem Gummi sowie der Haftung zwischen vulkanisiertem Gummi und vulkanisiertem Gummi.
