Polymers emulsions

Polymer electrolyte Polymer electrolytes Polymer emulsions Polymer flocculation Polymer gasoline... 

Acrylates are primarily used to prepare emulsion and solution polymers. The emulsion polymerization process provides high yields of polymers in a form suitable for a variety of appHcations. Acrylate polymer emulsions were first used as coatings for leather in the eady 1930s and have found wide utiHty as coatings, finishes, and binders for leather, textiles, and paper. Acrylate emulsions are used in the preparation of both interior and exterior paints, door poHshes, and adhesives. Solution polymers of acrylates, frequentiy with minor concentrations of other monomers, are employed in the preparation of industrial coatings. Polymers of acryHc acid can be used as superabsorbents in disposable diapers, as well as in formulation of superior, reduced-phosphate-level detergents. 

The inverse emulsion form is made by emulsifying an aqueous monomer solution in a light hydrocarbon oil to form an oil-continuous emulsion stabilized by a surfactant system (21). This is polymerized to form an emulsion of aqueous polymer particle ranging in size from 1.0 to about 10 pm dispersed in oil. By addition of appropriate surfactants, the emulsion is made self-inverting, which means that when it is added to water with agitation, the oil is emulsified and the polymer goes into solution in a few minutes. Alternatively, a surfactant can be added to the water before addition of the inverse polymer emulsion (see Emulsions). 

Soap-starved recipes have been developed that yield 60 wt % soHds low viscosity polymer emulsions without concentrating. It is possible to make latices for appHcation as membranes and similar products via emulsion polymerization at even higher soHds (79). SoHds levels of 70—80 wt % are possible. The paste-like material is made in batch reactors and extmded as product. 

The quahty of the water used in emulsion polymerization has long been known to affect the manufacture of ESBR. Water hardness and other ionic content can direcdy affect the chemical and mechanical stabiUty of the polymer emulsion (latex). Poor latex stabiUty results in the formation of coagulum in the polymerization stage as well as other parts of the latex handling system. 

Plasticization, whether internal (by copolymerization) or external (with additives), is also extremely important for proper performance at the time of apphcation. The ease of coalescence and the wetting characteristics of the polymer emulsion particles are related to their softness and the chemical nature of the plasticizer. 

Hydrophilic/hydrophobic properties. In water-based systems, the filler should be compatible with water because filler dispersion occurs in an aqueous medium before a polymer emulsion is added. In general, most fillers are hydropho-... 

A bond coat of a polymer latex (also called polymer emulsions or dispersions) such as styrene butadiene (SBR), polyvinyl acetate (PVA) acrylics or modified acrylics. These are applied to the prepared concrete as... 

If the polymer is to remain in emulsion form, it is important that the pH of the water phase remain at or above 8. If the pH of the water phase falls below 8, the polymer will commence dissolving in water, and the polymer emulsion will break. 

Liquid raw materials such as polymer emulsions, defoamers, pigment dispersions, dye solutions, dispersing aids and emulsifiers are all products that can themselves become infected with micro-organisms if not produced from non-contaminated ingredients, under good manufacturing conditions and with an effective preservative. 

DBR Kumar, MR Reddy, VN Mulay, N Krishnamurti. Acrylic co-polymer emulsion binders for green machining of ceramics. Eur Polym J 36(7) 1503—1510, 2000. 

Roodhart, L.P. Davies, D.R. "Polymer Emulsion The Revival of a Fracturing Fluid , SPE/DOE paper 16413, 1987 SPE/DOE Low Permeability Reservoirs Symposium, Denver, May 18-19. 

Krishan, K., Kapoor, S., and Goyal, K.L. "Development of Polymer Emulsion as Fracturing Fluid," Chemical Abstracts 103(20) 162915z(1985). 

Films of polyolefins, polyamides and poly(vinylidene dichloride) are made using this technique. As most of the films are used for flexible packaging, further down-stream surface treatments are usually applied to improve performance. For example, aqueous polymer emulsions, e.g., poly(vinylidene dichloride), or delaminated clay particles improve the barrier properties as will metallising with aluminium vapour. Corona discharge, causing slight surface oxidation, improves printability. 

Dispersion, Flaring, Scrubbing, and Containment An example of an overpressure protection system designed to reduce emissions to the atmosphere and at the same time provide adequate protection to the equipment has been described [234]. The equipment indicated is used for the manufacture of ethylene-vinyl acetate-vinyl chloride polymer emulsions. The design pressures are up to 100 bar. 

Fig. 9.16 Schematic illustration of drying process for SWNT-filled polymer emulsion. Initially the nanotubes and polymer particles are uniformly suspended in water (left). Once most of water has evaporated, the polymer particles assume a close-packed configuration with the nanotubes occupying interstitial space(center). Finally, the polymer particles will interdiffuse (i.e., coalesce) to forma coherent film, locking the SWNTs within a segregated network (right) (Keren et al, 2003. With permission from Wiley-VCH)...

With emulsion polymerization it is possible to prepare very high-molecular-weight polymers at high rates of polymerization. The required reaction temperatures are low and can even be below 20 °C when redox systems are used for initiation (see Examples 3-11). Polymer emulsions with solid contents of 50% and higher can be very stable. In many cases, e.g., poly(vinyl acetate), they are directly used as paints (paint latices), coatings, or adhesives (see Sect. 2.5.4). 

Latex originally meant the sap of the rubber plant and is a dispersion of particulate rubber. Emulsion polymerization produces a similar dispersion of synthetic rubber or polymers and was rapidly developed to obtain a substitute for natural rubber during World War II. Therefore the product of emulsion polymerization was first called polymer latex, but is now known simply as latex. Sometimes the product of emulsion polymerization is called polymer emulsion. But this terminology is incorrect for latices of solid polymer particles, because emulsion indicates liquid-in-liquid dispersion (1). 

Polymer Emulsion SBR Solution Butadiene/Styrene Copolymer Polar modif. 

One of the more advanced of the FFF techniques is sedimentation FFF (SdFFF), in which the applied field is a centrifugal force (see Fig. 2.1b). A typical separation achieved through SdFFF is also illustrated in Figure 2.1b. The SdFFF is suitable for species with molecular weights larger than about 106 and has proved useful for a large number of biocolloids (e.g., subcellular particles), polymers, emulsions, and natural and industrial colloids (Giddings 1991). 

Aqueous-based EVA polymer emulsions suited for the use in heat seal applications are produced at a comparatively low pressures process, less than 14 M Pa (2). 

The EVA polymer emulsions contain crystalline segments resulting from ethylene linkages. In addition to ethylene and vinyl acetate, a carboxylic comonomer is used, such as acrylamide or versa tic acid vinyl ester. The polymers have crystalline melting point of 50-90°C. 

J.J. Rabasco, G.J. Dearth, C.R. Hegedus, F.R. Pepe, and B.V. Mukku-lainen, Masonry sealing compositions comprising semi-crystalline ethylene-vinyl acetate polymer emulsions, US Patent 7459186, assigned to Wacker Chemical Corporation, December 2, 2008. 

Preparation of an aqueous elastomeric polymer emulsion of colloidally dispersed small particles with a particle size of 0.15-0.22 p,... 

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