Download or read book Investigation of Adhesion and Fracture of the Polymer oxide Interfaces Using Rolling Contact Mechanics written by Honquan She and published by . This book was released on 2002 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the very basic origin, the adhesion strength or fracture resistance of contacting interfaces results from intermolecular forces. When interface is separated, external energy is provided to the system, which eventually is dissipated in the form of mechanical deformation of the bulk material and cleavage of the interfacial bonds. The objective of this study is to understand the energy dissipation mechanism of interfacial fracture. It particularly includes polymer molecular weight and rate dependent properties of fracture. The model system consists of an oxidized polydimethylsiloxane(PDMS)-made hemicylinder and a PDMS thin films substrate, in which system energy is mainly dissipated at the interface layer. A unique experimental methodology---rolling contact mechanics method is developed by rolling the hemi-cylinder on the test substrate at a uniform velocity, the contact deformation of which is used to estimate the energy dissipation governed by non-equilibrium processes occurred at the interface. The strong molecular weight dependent fracture energy can be explained in terms of polymer chain extension and relaxation, which has its origins in the classic Lake-Thomas theory. The fracture energy is amplified by the molecular weights of polymers which bridge the open interface. The rate effect can be explained using the kinetic theory of thermally activated bond rupture, the results of which point out that this molecular weight dependent Lake-Thomas effect is purely a non-equilibrium effect and isn't compatible with the traditional notion of equilibrium fracture. The energy dissipation occurred at the interface can now be understood under the framework which combined chain elasticity and interfacial kinetics.

Download or read book Applications of Contact and Fracture Mechanics to Studies of Polymer Adhesion written by James Michael Baney and published by . This book was released on 2000 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Doctoral Dissertations written by and published by . This book was released on 2001 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adhesion and Adsorption of Polymers written by Lieng-Huang Lee and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: Honolulu is a most beautiful place, suitable for all occa sions. Its choice as the meeting site for the first Joint Chemical Congress between the American Chemical Society and the Chemical Society of Japan was praised by scientists from both sides. During this Congress, the International Conference on Adhesion and Adsorption of Polymers was held at the Hyatt Regency Hotel between April 2 and 5, 1979. We had speakers from ten nations presenting over forty papers related to the subject matter. It was a memorable event. Unlike our two previous adhesion symposia held in 1971 and 1975, this was the first time in the same conference that we discussed both adhesion and adsorption of polymers simultaneously. These two important phenomena are not only inter-related, but also equally important in adhesive technology as well as biochemical processes. The papers presented to this Conference deal with these two phenomena from both fundamental and practical viewpoints. Furthermore, with the advance of new surface analytical techniques, the actual, microscopic happenings at the interfaces can be pin pointed. Thus, characterization of interface became one of the major focuses of this Conference. As a result, a broad coverage of the subject matter includes statistical thermodynamics, surface physics, surface analysis, fracture mechanics, viscoelasticity, failure analysis, surface modification, adsorption kinetics, bio polymer adsorption, etc. Thanks to the diligence of our contri butors, we are now able to publish the final papers in these two volumes.

Download or read book Interfacial Phenomena in Adhesion and Adhesive Bonding written by Shin Horiuchi and published by Springer Nature. This book was released on 2023-10-26 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book reviews the recent research achievements of the investigation of interfacial phenomena in polymer/polymer and polymer/metal joint interfaces with the state-of-the-art analytical techniques not previously used in the field of adhesion and bonding. Adhesion performance is determined not only by the two-dimensional interfaces but also by a three-dimensional (3D) region having different properties and structural characteristics that extends into the bulk materials. In this book, the authors also discuss in detail the bonding mechanism by characterizing such 3D regions called “interphase”. The book is of great interest to researchers and engineers devoted to adhesion science and technology. Videos via app: download the SN More Media app for free, scan an image or a link with play button, and access videos directly on your smartphone or tablet.

Download or read book Experimental Investigation of Polymer Adhesion Mechanics Using a Blister Contact Test written by Nathan Ip and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The adhesion of thin layers of soft polymers is important in many applications, such as tapes, microtransfer printing, and bioinspired adhesives. Traditional adhesion tests based on probe contacts are not suitable for characterizing thin layers and common separation-based specimens, such as the peel test, have well-known limitations. The blister contact test (BCT) was developed in this dissertation to overcome the limitations of current methods and was used to investigate the adhesion and separation of several technologically relevant adhesive systems. In the BCT, a thin sheet was elastically deformed into adhesive contact with a reference substrate and the contact area was optically imaged. Modulated pressure was applied to generate both advancing and receding adhesive contact. Digital image correlation was used to measure the displacements of the specimen. The strain energy release rate at the interface was determined from the measured contact radius, applied pressure, system geometry, and elastic properties of the specimen using a mechanics model. An analytical mechanics model based on von Kármán plate theory was developed and used for analysis of the BCT data. Finite element analysis was used to validate and identify the range of applicability of the analytical model. The BCT was used to investigate the adhesion and separation behaviors of three different polymer adhesive systems. First, experiments between a silicone elastomer (polydimethylsiloxane--PDMS) and a stiff substrate were performed to investigate rate effects in adhesion and separation. For the first time, the rate dependence during advancing contact was characterized. Second, the effect of acid-base interactions on performance of pressure sensitive adhesives (PSAs) was examined via a series of BCTs in which adhesion between different formulations of adhesives and multiple substrates was investigated. Viscoelastic contributions to PSA adhesion were also studied. Finally, the effect of layer thickness on rate dependence was investigated through experiments between polyethylene terephthalate (PET) sheets and PDMS films of different thicknesses. The work in this dissertation demonstrates the flexibility and capability of the BCT as a method to characterize adhesion of flat polymer sheets and provides new understanding of several types of polymer adhesive contacts.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2002 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1987 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Contact Mechanics Studies of Polymer Thin Film Adhesion written by Rachel Lynn McSwain and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this dissertation focuses on using the unique abilities of the JKR technique to probe the interfacial interactions of two independent polymer systems. To perform these studies, modifications were made to the JKR technique, including the integration of a thermal cycle to enable testing of thermally initiated interfacial interactions between two materials. Another enhancement of the JKR technique involved incorporation of cyclic testing to study crack growth under fatigue conditions.

Download or read book Adhesion and Fracture of a Sol gel Reinforced Polymer metal Interface written by Jiong Liu and published by . This book was released on 2006 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Boeing sol-gel coating (Boegel-EPII), derived from an acid-catalyzed aqueous solution of organofunctional silane and zirconium alkoxide precursors, is being used as an adhesion promoter for adhesive bonding and painting applications in the aerospace industry. In this study, a fracture mechanics approach is used to investigate the adhesion properties and fracture behavior of a sol-gel reinforced epoxy/aluminum joint. An asymmetric double cantilever beam (ADCB) wedge test is employed which illustrates that both the fracture energy and locus of failure depend upon the mode mixity. The study starts with investigating the quasi-static fracture behavior of the sol-gel reinforced epoxy/aluminum interface under dry and wet conditions. Various loci of failure are observed for different surface pretreatments and sol-gel processing conditions. Strong experimental evidence shows that the room-temperature-dried sol-gel film is partially cross-linked and subject to moisture degradation. To further investigate the hydrolytic stability of the sol-gel, the ADCB test is modified such that the critical fracture energy, crack growth kinetics, and threshold fracture energy can be measured on a single sample. The effect of surface pretreatment on moisture-assisted crack growth is then studied in detail. It is found that the macro-roughness of the substrate enhances the initial strength of the sol-gel reinforced interface, whereas the micro-roughness is more effective than the macro-roughness in enhancing the durability. The fractal dimension of the macro-rough substrates shows a good correlation with the fracture energies. The following studies on sol-gel processing conditions show that the sol-gel drying time, film thickness and drying humidity all have a considerable effect on moisture-assisted crack growth of the sol-gel reinforced joints. Analysis of locus of failure reveals that most of the observed trends on adhesion kinetics can be explained in terms of interdiffusion of the sol-gel film and epoxy. The interdiffusion strongly depends on the degree of condensation of the sol-gel film, which is directly affected by the sol-gel processing conditions. Lastly, the environmental effects on crack growth at the sol-gel reinforced joint are investigated.

Download or read book Investigation of the Impact of Cleaning on the Adhesive Bond and the Process Implications written by and published by . This book was released on 2000 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: While surface cleaning is the most common process step in DOE manufacturing operations, the link between a successful adhesive bond and the surface clean performed before adhesion is not well understood. An innovative approach that combines computer modeling expertise, fracture mechanics understanding, and cleaning experience to address how to achieve a good adhesive bond is discussed here to develop a capability that would result in reduced cleaning development time and testing, improved bonds, improved manufacturability, and even an understanding that leads to improved aging. A simulation modeling technique, polymer reference interaction site model applied near wall (Wall PRISM), provided the capability to include contaminants on the surface. Calculations determined an approximately 8% reduction in the work of adhesion for 1% by weight of ethanol contamination on the structure of a silicone adhesive near a surface. The demonstration of repeatable coatings and quantitative analysis of the surface for deposition of controlled amounts of contamination (hexadecane and mineral oil) was based on three deposition methods. The effect of the cleaning process used on interfacial toughness was determined. The measured interfacial toughness of samples with a Brulin cleaned sandblasted aluminum surface was found to be (approximately) 15% greater than that with a TCE cleaned aluminum surface. The sensitivity of measured fracture toughness to various test conditions determined that both interfacial toughness and interface corner toughness depended strongly on surface roughness. The work of adhesion value for silicone/silicone interface was determined by a contact mechanics technique known as the JKR method. Correlation with fracture data has allowed a better understanding between interfacial fracture parameters and surface energy.

Download or read book Molecular Adhesion and Friction at Elastomer polymer Interfaces written by Betul Buehler and published by . This book was released on 2006 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have studied the contact interface between elastomeric poly(dimethyl siloxane) (PDMS) lenses with various solid surfaces during adhesion and friction using IRvisible sum frequency generation spectroscopy (SFG). SFG in total internal reflection geometry can be used to determine molecular structure at the polymer/solid and polymer/polymer contact interfaces. It is a nonlinear optical technique, which detects the orientation and density of molecules at interfaces. In this study, we have designed a novel approach to couple SFG with adhesion and friction experiments. The solid surfaces were chosen to be octadecytrichlorosilane monolayer (OTS), poly(vinyl noctadecyl carbamate-co-vinyl acetate) (PVNODC), polystyrene (PS), poly(n-butyl methacrylate) (PnBMA), and poly(n-propyl methacrylate) (PnPMA). In the first part of the research, we have concentrated on the importance of characterizing the static contact interface to understand adhesion. Our results for the contact between two macroscopic rough surfaces, OTS and oxygen plasma treated PDMS, show surprising surface restructuring, which results in adhesion hysteresis. The short PDMS chains generated during plasma treatment are locally confined between two flattened asperities and are as strongly ordered as OTS. SFG spectra from other surfaces (sapphire substrates and fluorinated monolayers) indicate that short PDMS chains require not only confinement but also an ordered template provided by the methyl groups of OTS. In the second part, we have studied the sliding contact interfaces of various polymers with PDMS. The friction forces between PDMS lenses and glassy PS are a factor of four higher than PDMS sliding on crystalline well-packed PVNODC surfaces. This cannot be explained by the difference in adhesion energy or hysteresis. The in-situ SFG measurements indicate local interpenetration during contact, which is evident from the change in orientation of PS phenyl groups upon mechanical contact and during sliding compared to that at the PS surface. Such a local penetration is unexpected at room temperature (T[subscript R]) that is much below the T[subscript g] of PS. For comparison, we have also studied PnBMA and PnPMA having T[subscript g] below and above T[subscript R], respectively. Preliminary studies at the contact and sliding interfaces with PDMS exhibited similar interpenetration based on adhesion, friction and SFG results regardless of the bulk T[subscript g]. Our results indicate that the adhesion energy and hysteresis of surfaces are not sufficient to predict their friction properties, which makes the characterization of the molecular structure at the static and dynamic contact essential. Finally, we have reported a fabrication process of constructing polymer surfaces with multiwalled carbon nanotube hairs. The force measurements with scanning force microscope indicated strong nanometer level adhesion forces, 200 times higher than those observed for Gecko foot-hairs. These forces are a combination of van der Waals forces and energy dissipation during the elongation of the carbon nanotubes which comes from their material properties.

Download or read book Adhesion Science and Engineering written by and published by Elsevier. This book was released on 2002-11-14 with total page 2020 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mechanics of Adhesion shows that adhesion science and technology is inherently an interdisciplinary field, requiring fundamental understanding of mechanics, surfaces, and materials. This volume comprises 19 chapters. Starting with a background and introduction to stress transfer principles; fracture mechanics and singularities; and an energy approach to debonding, the volume continues with analysis of structural lap and butt joint configurations. It then continues with discussions of test methods for strength and constitutive properties; fracture; peel; coatings, the case of adhesion to a single substrate; elastomeric adhesives such as sealants. The role of mechanics in determining the locus of failure in bonded joints is discussed, followed by a chapter on rheology relevant to adhesives and sealants. Pressure sensitive adhesive performance; the principles of tack and tack measurements; and contact mechanics relevant to wetting and surface energy measurements are then covered. The volume concludes with sections on fibermatrix bonding and reinforcement; durability considerations for adhesive bonds; ultrasonic non-destructive evaluation of adhesive bonds; and design of adhesive bonds from a strength perspective. This book will be of interest to practitioners in the fields of engineering and to those with an interest in adhesion science.

Download or read book Interface Dynamics written by D. Berthe and published by Elsevier. This book was released on 1988-09-01 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many tribologists are today not only explicitly concerned with interface action but also with interface composition. This proceedings volume presents a timely review on topics ranging from interface dynamics to interface elimination, covering all factors such as contact stress fields, interface rheology, and boundary slip, that control the passage from formation to elimination. The volume contains 45 papers divided into 13 sessions, that were presented at the symposium.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1988 with total page 968 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metals Abstracts written by and published by . This book was released on 1998 with total page 1076 pages. Available in PDF, EPUB and Kindle. Book excerpt: