Emulsions, adhesive

Rgure 2.30. Two adhesive emulsion droplets. A flat hquid fllm stabilized by the surfactant layers is located between the droplets. This fllm being very thin, it can be usually considered as a surfactant bilayer. Yf is the tension of the fllm and y nt the tension of single isolated interface. 

Rgure 2.31. Two adhesive emulsion droplets of few tens of microns. The adhesion induces the formation of a large contact angle of about 40°. (Reproduced from [113], with permission.)... 

The study of inverse adhesive emulsions has revealed the same features as direct emulsions [112,113]. Here again, it was shown that adhesion is favored when the surfactant becomes less soluble in the continuous phase [113]. This can be tested experimentally by using binary mixtures of oils, one in which the surfactant is soluble and another one in which the surfactant is insoluble. For example, water droplets can be stabilized in mineral oil by sorbitan monooleate (Span 80). This surfactant is soluble in dodecane whereas it is not in silicon oil. The affinity of the surfactant for the organic solvent can be tuned by mixing dodecane and silicon oil. As shown in Fig. 2.38, the energy of adhesion between water droplets strongly varies as the ratio of the mixture is changed. A sharp rise is noted as the surfactant... 

P. Poulin, F. Nallet, B. Cabane, and J. Bibette Evidence for Newton Black Films Between Adhesive Emulsion Droplets. Phys. Rev. Lett. 77, 3248 (1996). 

Finally, an important feature of gels made of adhesive emulsions arises from the deformation of the droplets. Indeed, as the temperature is lowered the contact angles between the droplets increase [27,28] (see Chapter 2, Section 2.3). Consequently, the structure of the final floes depends on the time evolution of the strength of the adhesion. Initially, the adhesion results in the formation of a random, solid gel network in the emulsion. Further increase of adhesion causes massive fracturing of the gel, disrupting the rigidity of the structure and leading to well separated, and more compact floes [27,28]. 

Because of the widespread applications of surface chemistry, practically all industries, knowingly or otherwise, make use of the principles of surface chemistry. Countless cosmetic and pharmaceutical products are emulsions—lotions, creams, ointments, suppositories, etc. Food emulsions include milk, margarine, salad dressings and sauces. Adhesive emulsions, emulsion paints, self-polishing waxes, waterless hand cleaners and emulsifiable insecticide concentrates are commonplace examples of emulsions, which fall within the province of surface chemistry. Other products winch function in accordance with the principles of smface chemistry include detergents of every variety, fabric softeners, antistatic agents, mold releases, dispersants and flocculants. 

Some physicochemical properties and applications of oligomethylsiloxanes are given in Table 15. As seen from the table, PMS-300, PMS-400 and PMS-500 oligomethylsiloxane brands can be used as a basis in the production of mineral butters, anti-foaming and anti-adhesion emulsions. 

Epoxy adhesives should be 100 percent solids so as to eliminate the possibility of gassing and bubbles occurring in the bond line. However, dielectric heating is often used in the furniture industry to drive off water quickly from water-based adhesive emulsions. Water, being a polar material, heats rapidly in a microwave field, as every cook knows. 

Adhesive Emulsions. Thermoplastic, synthetic polymers can be prepared as emulsions for use as adhesives. For example, while EVAc hot-melt adhesives described in the previous section contain less than 40% VAc, when the content of VAc in the copolymer is increased to 60%, and the copolymer is prepared in the form of aqueous emulsions, a very useful and versatile adhesive polymer is obtained. Although the VAc homopolymer, poly(vinyl acetate), is a brittle solid, with a Tg = 28 °C, the ethylene units present in the EVAc copolymer act as an internal plasticizer, and lower the Tg to below room temperature. The plasticization results from the reduction of interchain interaction of the VAc polymer chains by the ethylene units interspersed among the strongly interacting VAc units. This reduction of the Tg has important consequences because the formation of a flexible adhesive film from the emulsion depends upon the Tg of the polymer. 

Use Adhesives, emulsions, polymerization, film coatings, polyester release agents, textile printing, finishing, and sizing. 

Polymers and Related Products synthetic resins resin and polymer intermediates resin products adhesives emulsions plasticisers fluorochemi-cals. In general the overseas activities are undertaken by Reichhold Specialty Plastics and Compounds engineering and high performance plastics colourants molded plastic products ... 

Daratak . [WJl. Grace/Organics] PVAc emulsions adhesive emulsion for textiles, surface coatings, heat sealing, mastics, food pkg., paper saturadon, laminadon. 

Orevac . [Atochem N. Am. Atochem UK] Polyethylene, prc yletie, or EVA tetpolymers for blown film coexttu-sion, cast film co itrusion, extrusion codng, skin pkg. adhesive, adhesive emulsions. 

Robond. [Rohm Haas] Waterborne adhesive emulsions for construction, pkg., pressure-sensitive applies. 

More than half of vinyl acetate monomer is used in polyvinyl acetate emulsions and resins. The largest use of polyvinyl acetate emulsions is in adhesive emulsions. This is followed by use in copolymers to produce latex paints which have largely replaced solvent-based paints in developed countries. The adhesive emulsions are used in all types of consumer adhesives and glues used in the construction industry. 

Among the commercially available families of PSA one distinguishes three large groups solvent-borne acrylic adhesives emulsion acrylic adhesives and block copolymer based adhesives [27]. The block copolymer based adhesives are typically formulated as a blend of one or several block copolymers and one or several tackifying resins. The block copolymers are based on a glassy monomer such as styrene and an elastomeric monomer such as isoprene or butadiene. The glassy sequence is the minority phase (15-30 wt%) and diblock and tri-... 

Uses Dispersant for water treatment boiler water (food contact) modifier for aq. formulations, cleaners, binders, adhesives, emulsion paints in reproduction processes ceramic applies. its salts as thickeners and dispersants for latex systems food pkg. adhesives, paper/paperboard Regulatory FDA 21CFR 173.310,175.105,176.170 Properties Colorless clear vise, liq. infinite dilutability with water m.w. = 60,000 vise. 160 cps pH 2 (5% aq.) 25% solids Toxicology LD50 (oral, rat) > 5 g/kg, (dermal, rabbit) > 3 g/kg causes eye damage and si. skin irritation vapors may be irritating to eyes and respiratory tract, and cause headache and nausea in poorly ventilated areas Acumer 1850 [Rohm Haas]... 

Chem. Descrip. Med. to high m.w. polymeric plasticizer Uses Plasticizer for adhesives (emulsion, solv., hot-melt), heat-resist, lacquers, barrier coalings (oil, fats, hydrocarbons), paints, sealants binder sizing agent for glass fibers... 

Chem. Descrip. Polysiloxane copolymer emulsion in water Uses Defoamer for aq. systems, architectural coatings, building prods., industrial and wood coatings, printing inks, adhesives, emulsions Features Exc. stability resist, to acid and alkaline environment suitable for use at pH 2-11... 

Uses Antifoam, defoamer for water-based coatings, adhesives, emulsion-based systems, wide range of resins ind. acrylics, vinyl acrylics, PVAc, water-reducible alkyds defoamer in food-contact paper/paperboard... 

Chem. Descrip. Tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione CAS 533-74-4 EINECS/ELINCS 208-576-7 Uses Bactericide for use in coatings, adhesives, emulsions, day slurries, leather food-contact paper/paperboard food-contact slimidde Features Broad-spectrum protects against bacterial attack during shipping and storage... 

Uses Bactericide for use In coatings, adhesives, emulsions, and clay... 

Uses Adhesive emulsion for primer sealers, textile finishes, and paper saturation... 

Chem. Descrip. Blend of organics and hydrocarbons Uses Defoamer, antifoam for latex paints (acrylic, vinyl acrylic, S/B), coatings, Ink, adhesives, emulsions... 

Uses Detoamer for syn. latex, mat aq. coatings, aq. architectural coatings, plasters based on organosilicate, aq. adhesives, emulsion polymerization... 

Chem. Descrip. Smectite CAS 53320-86-8 EINECS/ELINCS 258-476-2 Uses Thixotrope, thickener for latex emulsion systems incl. coatings, sealants, and adhesives emulsion stabilizer for cosmetics and pharmaceuticals... 

Uses Functional monomer for hydrogels, antistatics, adhesives, emulsions, paints and inks Trade Names SPE... 

Uses Monomer for plastics, molding powds. lube oil additive pour pt. depressant paper coatings textile finishes paints, varnishes pressure-sensitive adhesives emulsions for textile, leather, paper finishing modifier for fibers coating agent for papers ManufJDIstrlb. Aldrich CPS Rohm Haas Rohm Tech Sartomer Trade Names Ageflex FM-68 Lubrizol 2509 Mhoromer BM 174 SR 324... 

Synonyms 1 -(3-Sulfoprop-1 -yl)-2-vinylpyridinium betaine Uses Functional monomer for hydrogels, antistatics, adhesives, emulsions, paints and inks additive for electroplating baths Manuf./Distrib. ABCR Trade Names SPV... 

It has been reported in the literature that amphiphilic diblock copolymers can be synthesized by anionic polymerization by incorporating a new approach called oxyanion-initiated polymerization to combine tertiary amine methacrylates, such as 2-(N-morphoIino)ethyI methacrylate (MEMA), t-(butylamino)ethyl methacrylate (BAEMA), 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA), and 2-(N,N-diethylamino)ethyl methacrylate (DEAEMA). " " Such materials have been considered for various applications as adhesives, emulsion and dispersion stabilizers, wastewater treatment formulations, and biomaterials. 

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