Adhesive compositions

Production of pentaerythritol in the United States has been erratic. Demand decreased in 1975 because of an economic recession and grew only moderately to 1980 (69). The range of uses for pentaerythritol has grown rapidly in lubricants (qv), fire-retardant compositions, adhesives, and other formulations where the cross-linking capabiUties are of critical importance. 

Sodium Metaborate Tetrahydrate and Dihydrate, The sodium metaborates are components in textile finishing, sizing and scouring compositions, adhesives, and detergents. They are also used in many photographic apphcations. In agriculture they are used in both herbicides and fertilizer sprays. The dihydrate is less affected by heat. 

Polyimide laminates, 20 285 Polyimide matrix composites/adhesives, 20 284... 

Aerospace (wiring and cables, composites, adhesives, repairs, and marking)... 

Title Novel Sulfur-containing Phenolic Resin, Process for Preparing the Same, Phenol Derivatives Having Thioether Structure or Disulfide Structure, Process for Preparing the Same and Epoxy Resin Composition Adhesive... 

Most laminated safety glazings are glass-PVB-glass trilayer composites. Adhesion of plasticized PVB to clean glass is very high. 

For photochemical aging, it is well known that photooxidation affects only a thin superficial layer directly exposed to solar radiation - a few dozens of micrometers in the case of epoxies (Bellenger and Verdu, 1983). Thus the aging mode cannot control the material s lifetime in most cases (composites, adhesives), except for applications such as, for example, varnishes of automotive bodies (Bauer et ah, 1992). 

Both polyimides and epoxy have found widespread use in many diverse industries. Polyim-ides, due to their excellent thermal and chemical stability and low dielectric constant, have become a favorite of the electronics industry. This broad class of polymers has found widespread use in a variety of electronic applications and the low cost has made epoxy popular as matrix materials in composites, adhesives and coatings. 

There have been many attempts to replace these resins with lignin derivatives for wood composite adhesives suitable for plywood, particleboard and waferboard. Most of these studies have been empirical in nature, and few have achieved further consideration for industrial application. As wood binders, technical lignins are variable in quality and poorly reactive in comparison to conventional resin systems such as phenol-formaldehyde (PF) resins. Consequently, they are not utilized on their own. Indeed, if they were, this would adversely affect production quality and times, and necessitate equipment changes. In the wood composite industry, resins having such deleterious effects are not likely to be used even if savings could be made in terms of material costs. 

Steam-explosion lignins have received some attention as adhesives mainly because this process offers some potential for utilizing low-quality hardwoods. Like kraft lignin, these preparations also require activation [e.g., by hydroxymethy-lation (70), isocyanation (75,80)] to achieve any type of acceptable wood composite adhesive properties. 

Considerable research activity has been directed toward producing wood composite adhesives from lignin, and this has been accompanied by very little practical success in terms of commercial implementation. By themselves, and regardless of source, lignins offer no advantages in terms of chemical reactivity, product quality, or color when compared to conventional wood composite adhesives. At low replacement levels (10 to 30%), lignins can and will continue to be employed as extenders for UF and PF resins. When they are used as extenders, best results are obtained when chemically activated (e.g., by methylolation). 

However, lignin may find application as a suitable wood-composite adhesive in adhesive formulations if chemically modified in some manner. In this respect, the recent developments with soda bagasse lignin-resorcinol-formaldehyde and lignin-isocyanate adhesives allow for some cautious optimism for the future. 

The rheological equipment requires certain capabilities in order to effectively measure composite adhesive resin systems. The transducer must have a dynamic range from 1 to 10 poise. This is a result of achieving a very low viscosity during an elevated temperature cure... 

The paper is presented in three parts. First, the tests employed to determine the mixed mode fracture envelope of a glass fibre reinforced epoxy composite adhesively bonded with either a brittle or a ductile adhesive are briefly described. These include mode I (DCB), and mixed mode (MMB) with various mixed mode (I/II) ratios. In the second part of the paper different structural joints will be discussed. These include single and double lap shear and L-specimens. In a recent European thematic network lap shear and double lap shear composite joints were tested, and predictions of failure load were made by different academic and industrial partners [9,10]. It was apparent that considerable differences existed between different analytical predictions and FE analyses, and correlation with tests proved complex. In particular, the progressive damage development in assemblies bonded with a ductile adhesive was not treated adequately. A more detailed study of damage mechanisms was therefore undertaken, using image analysis combined with microscopy to examine the crack tip strain fields and measure adherend displacements. This is described below and correlation is made between predicted displacements and failure loads, based on the mixed mode envelope determined previously, and measured values. 

Roy, C., Calve, L., Lu, X., Pakdel, H., and Amen-Chen, C. (1999) Wood Composite Adhesives from Softwood Bark-Derived Vacuum Pyrolysis Oils.In Biomass A Growth Opportunity in Green Energy and blue Added Products. 

Himmelblau D.A., Grozdits G. A. and Gibson M. A. (2000) Performance of Wood Composite Adhesives Made With Biomass Pyrolysis Oil To be published as part of fVood Adhesives 2000, Forest Products Society, Madison, WI. 

Himmelblau D.A. and Grozdits G.A. (1999) Production and Performance of Wood Composite Adhesives with Air-Blown, Fluidized-Bed Pyrolysis Oil. hiPrvceedings. Fourth Biomass Conference of the A mericas, Elsevier, New York. 

Use Waterproofing compositions, adhesives, driers, wood fillers, grafting waxes, cements, varnishes, color lakes. 

Use Imparts water tolerance and vapor permeability to copolymer films latex and water-based coating compositions adhesion improver for cellulosics, concrete, glass cross-linking agent in polyester resins color photography. 

Use Solvent and plasticizer, lacquers, varnishes, coating compositions, adhesives. 

Use Fibers, composites, adhesives (high adhesion to steel, titanium, beryllium, and aluminum alloys), coatings, ablative materials. 

It is shown that the composite adhesion or bond quality is dependent on the PA-6 modification as examined by tensile test. The processing parameters are not optimised to obtain the highest values for the tensile strength. The aim of this investigation was the determination of the influence of the increase of carboxylic acid... 

Laminates (multilayer structures), where each layer itself may be either a single-phase material or a multiphase material [10]. Examples of laminates include some electronic components, many structural composites, adhesive joints, and any other fabricated article where a coating layer (such as an anticorrosion coating or paint) is deposited on another material. See sections 7.C and ll.C.S.d for earlier discussions of such structures in this book. 

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