Silane Coupling Agents

* It has been rumored that a bumble bee has such aerodynamic deficiencies that it should be incapable of flight. Fiberglass-reinforced polymer com posites, similarly, have two (apparently) insurmountable obstacles to per formance: 1) Water can hydrolyze any conceivable bond between organic and inorganic phase, and 2) Stresses across the interface during temperature cycling (resulting from a mismatch in thermal expansion coefficients) may exceed the strength of one of the phases. Organofunctional silanes are hybrid organic-inorganic compounds that are used as coupling agents across the organic-inorganic interface to help overcome these two obstacles to composite performance. One of their functions is to use the hydrolytic action of water under equilibrium condi tions to relieve thermally induced stresses across the interface. If equilib rium conditions can be maintained, the two problems act to cancel each other out. Coupling agents are defined primarily as materials that improve the practical adhesive bond of polymer to mineral. This may involve an increase in true adhesion, but it may also involve improved wetting, rheology, and other handling properties. The coupling agent may also modify the inter phase region to strengthen the organic and inorganic boundary layers.

* Much progress has been made in the last 8 years in understanding the theory and practice of silane coupling agents. A major advance in this direction was the measurement of true equilibrium constants for the hydroly sis and formation of siloxane bonds. Equilibrium constants for bond reten tion are so favorable that a silane coupling agent on silica has a thousandfold advantage for bond retention in the presence of water over an alkoxysilane bond formed from hydroxy-functional polymers and silica. In practice, the bonds of certain epoxies to silane-primed glass resist debonding by water about a thousand times as long as the epoxy bond to unprimed glass. Oxane bonds of silane coupling agents to metal oxides seem to follow the same mechanism of equilibrium hydrolysis and rebonding, although equilibrium constants have not been measured for individual metal-oxygen silicon bonds. This suggests, however, that methods of improving bond retention to glass will also improve the water resistance of bonds to metals. of standard coupling agents with a hydrophobic silane or one Modification with extra siloxane cross-linking have improved the water resistance of bonds to glass and metals another hundredfold over that obtained with single coupling agents.

This book embodies the proceedings of the Second International Symposium on Silanes and other Adhesion Promoters held in Newark, New Jersey, October 21--23, 1998. Silanes are the most popular and widely used coupling agents (or adhesion promoters) to promote adhesion between dissimilar materials in a variety of situations, e.g. coating technology, adhesive bonding, reinforced composites, etc. Since the first symposium on this topic in 1991, there had been a tremendous R&D activity in developing new and more effective adhesion promoters and in understanding and optimising the performance of available coupling agents. The technical program for the symposium contained 36 papers and reflected both overviews and original research contributors and the presenters hailed from academia, industry and other research laboratories. Many different aspects of coupling agents were discussed, and both fundamental and applied aspects were accorded due coverage. In addition to formal presentations, there were brisk and lively discussions throughout the symposium, and this event provided an opportunity for cross-pollination of ideas in the broad arena of adhesion promoters. This present volume contains 18 papers by experts from academia, industry and other research laboratories. All manuscripts were subjected to rigorous peer review and were suitably revised before inclusion in this volume. The book is divided into two parts as follows: Part 1. Silane Coupling Agents; and Part 2: Non-silane Coupling Agents/Adhesion Promotors. The topics covered include: silane adhesion prompters for hydrosilylation cure systems; sterically hindered silanes; study of silanes hydrolysis; adsorption of silanes on different substrates; interaction of water with silane films studied by neutron reflection; characterization of glass fiber sizings; silanes as dispersion promoters; corrosion protection of metals by silanes; surface 'Intelligraft' as a new class of adhesion promoters; hydroxymethylated resorcinol, sol-gels, and -diketone functionalised polymers as adhesion promoters; and plasma deposition of silanes.

This volume chronicles the proceedings of the Fourth International Symposium on Silanes and Other Coupling Agents.This volume and its predecessors containing bountiful information should serve as a reference source for the latest R&D activity in the arena of coupling agents. Anyone interested or involved in promoting adhesion between dissimilar materials for any application should find this volume of great use and value.

This volume chronicles the proceedings of the Fourth International Symposium on Silanes and Other Coupling Agents held under the aegis of MST Conferences, LLC in Orlando, FL, June 11-13, 2003. Silanes have been used for about half a century as coupling agents / adhesion promoters to promote adhesion between dissimilar materials in a variety of situations, e.g., coating technology, adhesive bonding, and reinforced composites. However, recently silanes have found other applications, for example, as corrosion inhibitors. Lately there has been tremendous R&D activity in understanding the mechanisms by which silanes work as well as in devising new and improved silanes. This volume contains a total of 16 papers which were properly peer reviewed, revised and edited. The book is divided into two parts: 1. Silane Coupling Agents; and 2. Other Coupling Agents / Adhesion Promoters. Topics covered include: sterically hindered silanes; silane hydrolysis; silane oligomers; adsorption of silanes and their surface characterization; structure of bis-silane water-barrier films; silanes for improving adhesive bonding of aluminim, elastomer-to-metal adhesive bonds, and adhesion in silica-filler tire-tread compounds; electrodeposition of bis-silanes; silanes to provide corrosion resistance and as corrosion fatigue inhibitors; silane and other treatments for musical instrument strings; cyclic azasilanes as coupling agents for nanotechnology; hybrid polymers based on silanes for coating textile fabrics; plasma copolymers as adhesion promoters; organophosphate adsorption; and activation of wood fibres. This volume and its predecessors containing bountiful information should serve as a reference source for the latest R&D activity in the arena of coupling agents. Anyone interested or involved in promoting adhesion between dissimilar materials for any application should find this volume of great use and value.

The topic of silanes and other coupling agents/adhesion promoters is of tremendous contemporary interest because of their application in many and varied technologically important areas ranging from coatings to reinforced composites to dentistry to biomedical (e.g., for bonding nucleotides to the so-called ‘gene chips’). In addition to their traditional use for bonding different materials, silanes have been shown to be highly effective in corrosion protection of metallic materials. This book is divided into three parts as follows: Part 1: Silane Coupling Agents/Adhesion Promoters; Part 2: Silanes for Corrosion Inhibition/Protection; Parts 3: General papers. The topics covered include: various ways to deposit silanes and factors affecting silane deposition and silane deposit characteristics; structure of silane deposits; silane deposition on glass and other surfaces; hydrophobic silane films; water absorption and transport in silane films; application of silanes in fiber-reinforced composites for dental use in cathodic delamination of elastomer-metal adhesive joints, and to impart anti-mold and anti fungal characteristics to wood; use of silanes in providing corrosion protection to metallic materials and in enhancing corrosion performance of coatings; plasma polymer coatings in corrosion protection of metallic materials; chromata-free silane-containing primer technology; silane coupling agents for surface-initiated living polymerization; nanosols to improve functional properties of fabrics; photocatalytic titania for textile application; solid-state NMR studies of surface treatments; surface free energy of silicon-based plasma polymer films. In essence this book reflects the latest R&D activity in this arena and should be of interest and value to anyone with a desire or need to learn about this fascinating and technologically highly significant class of materials.

This book chronicles the proceedings of the Fifth International Symposium held on this topic in Toronto. A total of 26 papers covering many ramifications of silanes and other coupling agents are included in this book. The topics covered include: various ways to deposit silanes; silane adsorption; investigation of interfacial interactions between si

This book chronicles the proceedings of the Fifth International Symposium held on this topic in Toronto. A total of 26 papers covering many ramifications of silanes and other coupling agents are included in this book. The topics covered include: various ways to deposit silanes; silane adsorption; investigation of interfacial interactions between silanes and substrates; factors affecting effectiveness of silanes as adhesion promotors; silanes for corrosion inhibition/protection; application of silanes in a variety of technological areas; silanes in dental biomaterials, in understanding cellular adhesion, and in the field of textiles; and other (non-silane) coupling agents. This book provides a wealth of latest information on this highly technologically important topic and anyone interested in the use of these materials will find this book of great value and interest.