Adhesion surfactants

Block copolymers have become increasingly important in recent decades. This importance is due to the fact that their special chemical structure yields unusual physical properties, especially as far as solid-state properties are concerned. Block copolymers are applied in various fields, they are used as surfactants, adhesives, fibres, thermoplastics, and thermoplastic elastomers. 

Overall, the key element in many of these approaches is the complex needs of the ink to meet the needs of the deposition technique, to facilitate the formation of the desired material with appropriate properties and to facilitate the desired thickness, roughness, line resolution, and uniformity. This set of constraints will in most cases require an appropriate combination of precursors, solvents, surfactants, adhesion promoters, and rheology control agents (e.g., see Chapter 12 for more discussion).29 For new metal organic and nanoparticle precursors, the fabrication of inks is still an emerging science. 

The formulation which best suits the chemical and physico-chemical properties of the compound and satisfies the demands of application technology is then elaborated, i.e. by adding dispergents, surfactants, adhesion-increasing and other... 

Hazardous Decomp. Prods. CO, CO2, NO, hydrogen cyanide NFPA Flealth 4, Flammability 3, Reactivity 2 Uses Monomer for acrylic and modacrylic fibers, paints in prod, of ABS and SAN copolymers, nitrile rubber, surfactants, adhesives, polyols, barrier resins, carbon fibers organic synthesis formerly as pesticide fumigant... 

Ammonium laureth sulfate Nonoxynol-34 surfactant, adhesives... 

To illustrate another component of the forest products industry it may be instructive to take a brief look at the pine chemicals industry. The pine chemicals industry is not a new industry, but it is a very small portion of what is now known as the specialty chemicals industry, despite the fact that pine chemicals have been in active use for longer than the modern chemical industry era that arose in the early part of the 20th century. The pine chemicals industry has been extracting useful products such as turpentine and other simple materials for literally hundreds of years. With the rise of the pulp and paper industry, chemicals have in the majority been extracted from two waste streams crude tall oil and crude sulfate turpentine. Crude tall oil can be further separated into a fatty acid fraction, a tall oil fraction, a tail oil rosin fraction, and a tall oil pitch fraction. The crude sulfate fraction is separated into a variety of terpene monomers that can be further transformed into a variety of terpene resins. AH of these streams can be used as raw materials for coatings, various oil applications, surfactants, adhesives, inks, etc. [50]. 

Coatings, surfactants, adhesives Butadiene Belgium 617,612 1962 Shell International... 

This topic is dealt with in great detail by Uno and Tanaka [45-47]. Apart from the energies of repulsion and attraction due to adsorption of surfactants, adhesion may result from crystallization under the special conditions that obtain when particles are left behind after drainage of the bulk phase. Particles will be trapped by the surface tension of the liquid film (Fig. 9.18). As the particle dissolves there is supersaturation followed by deposition of the solid around the particle. According to Uno and Tanaka the solubility of the suspension particle increases at the particle-wall contact point due to the pressure exerted on the particle by the surface tension forces. Following deposition, evaporation of the continuous phase occurs as depicted in Fig. 9.18 [46]. Deposition due to cooling, to medium evaporation and to the adhesiveness of additives in the formulation can occur. The effect of polysorbate 80, benzethonium chloride, some anionic surfactants and poloxamers on the adhesion of chloramphenicol suspensions has... 

Several other half-empirical scales of surfactant emulsifying action have been proposed. Beerbower and Hill introduced the Cohesive Energy Ratio (CER), defined as the ratio of the surfactant adhesion energy to the oil phase to the surfactant adhesion to the water phase. The calculation of adhesion energies is done in terms of the Hildebrand solubility parameters. Kruglyakov et alP proposed the Hydrophile-Lipophile Ratio (HLR), which is the ratio of the energy of adsorption of the surfactant molecule from the water phase to its energy of... 

Syloid 244FP surfactant, adhesives Abex 18S Abex 22S Abex EP-110 Adekanol L-61 Adekanol TR-701 Ammonium nonoxynol-4 sulfate Ammonium nonoxynol-9 sulfate Brij C2 Brij ... 

Yamada S and Israelachvili J N 1998 Friction and adhesion hysteresis of fluorocarbon surfactant monolayer-coated surfaces measured with the surface forces apparatus J. Rhys. Chem. B 102 234-44... 

Emulsion Adhesives. The most widely used emulsion-based adhesive is that based upon poly(vinyl acetate)—poly(vinyl alcohol) copolymers formed by free-radical polymerization in an emulsion system. Poly(vinyl alcohol) is typically formed by hydrolysis of the poly(vinyl acetate). The properties of the emulsion are derived from the polymer employed in the polymerization as weU as from the system used to emulsify the polymer in water. The emulsion is stabilized by a combination of a surfactant plus a coUoid protection system. The protective coUoids are similar to those used paint (qv) to stabilize latex. For poly(vinyl acetate), the protective coUoids are isolated from natural gums and ceUulosic resins (carboxymethylceUulose or hydroxyethjdceUulose). The hydroHzed polymer may also be used. The physical properties of the poly(vinyl acetate) polymer can be modified by changing the co-monomer used in the polymerization. Any material which is free-radically active and participates in an emulsion polymerization can be employed. Plasticizers (qv), tackifiers, viscosity modifiers, solvents (added to coalesce the emulsion particles), fillers, humectants, and other materials are often added to the adhesive to meet specifications for the intended appHcation. Because the presence of foam in the bond line could decrease performance of the adhesion joint, agents that control the amount of air entrapped in an adhesive bond must be added. Biocides are also necessary many of the materials that are used to stabilize poly(vinyl acetate) emulsions are natural products. Poly(vinyl acetate) adhesives known as "white glue" or "carpenter s glue" are available under a number of different trade names. AppHcations are found mosdy in the area of adhesion to paper and wood (see Vinyl polymers). 

Dispersion Processing. A commercial aqueous dispersion of Teflon PEA 335 contains more than 50 wt % PEA particles, about 5 wt % surfactants and fillers. This dispersion is processed by the same technique as for PTEE dispersion. It is used for coating various surfaces, including metal, glass, and glass fabrics. A thin layer of Teflon PEA coating can also serve as an adhesive layer for PTEE topcoat. 

MIBK is a highly effective separating agent for metals from solutions of their salts and is used in the mining industries to extract plutonium from uranium, niobium from tantalum, and zirconium from hafnium (112,113). MIBK is also used in the production of specialty surfactants for inks (qv), paints, and pesticide formulations, examples of which are 2,4,7,9-tetramethyl-5-decyn-4,7-diol and its ethoxylated adduct. Other appHcations include as a solvent for adhesives and wax/oil separation (114), in leather (qv) finishing, textile coating, and as a denaturant for ethanol formulations. 

Applications. These materials are stiU in developmental infancy. Current production is limited to one commercial process in Europe and a demonstration-scale process in North America. The lignins produced in these processes have potential appHcation in wood adhesives, as flame retardants (qv), as slow-release agents for agricultural and pharmaceutical products, as surfactants (qv), as antioxidants (qv), as asphalt extenders, and as a raw material source for lignin-derived chemicals. 

Low molecular cationic polymers or alum can also be used to flocculate pitch, ie, bind up the pitch so that it is retained in the sheet, to minimize pitch deposition on machine surfaces and fabrics (35,36). Alum is used commonly in newsprint operations (34). The addition of a nonionic surfactant with a hydrocarbon solvent to the wet end has shown some utility in preventing deposits of adhesive recycled furnish contaminants from forming on the paper... 

High purity 4-dodecylphenol is used to produce specialty surfactants by its reaction with ethylene oxide. The low color of high purity 4-dodecylphenol is important in this appHcation from a standpoint of aesthetics. 4-Dodecylphenol is also used to produce phenoHc resins which are used in adhesive appHcations and printing inks. 4-Dodecylphenol is also used as an epoxy curing catalyst where the addition of 4-dodecylphenol accelerates curing of the epoxy resin to a hard, nontacky soHd. 

Patterns of ordered molecular islands surrounded by disordered molecules are common in Langmuir layers, where even in zero surface pressure molecules self-organize at the air—water interface. The difference between the two systems is that in SAMs of trichlorosilanes the island is comprised of polymerized surfactants, and therefore the mobihty of individual molecules is restricted. This lack of mobihty is probably the principal reason why SAMs of alkyltrichlorosilanes are less ordered than, for example, fatty acids on AgO, or thiols on gold. The coupling of polymerization and surface anchoring is a primary source of the reproducibihty problems. Small differences in water content and in surface Si—OH group concentration may result in a significant difference in monolayer quahty. Alkyl silanes remain, however, ideal materials for surface modification and functionalization apphcations, eg, as adhesion promoters (166—168) and boundary lubricants (169—171). 

Poly(vinyl acetate) emulsions can be made with a surfactant alone or with a protective coUoid alone, but the usual practice is to use a combination of the two. Normally, up to 3 wt % stabilizers may be included in the recipe, but when water sensitivity or tack of the wet film is desired, as in some adhesives, more may be included. The most commonly used surfactants are the anionic sulfates and sulfonates, but cationic emulsifiers and nonionics are also suitable. Indeed, some emulsion compounding formulas require the use of cationic or nonionic surfactants for stable formulations. The most commonly used protective coUoids are poly(vinyl alcohol) and hydroxyethyl cellulose, but there are many others, natural and synthetic, which are usable if not preferable for a given appHcation. 

Block copolymers have become commercially valuable commodities because of their unique stmcture—property relationships. They are best described in terms of their appHcations such as thermoplastic elastomers (TPE), elastomeric fibers, toughened thermoplastic resins, compatibilizers, surfactants, and adhesives (see Elastot rs, synthetic—thermoplastic). 

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