Thickeners, synthetic

All of the following are recommended for thickening synthetic latices, particularly RHOPLEX acrylic emulsions for standard backcoating, flocking, and laminating applications. They can be Incorporated directly into the binder system thickening begins with the addition of base to the proper pH. 

An ammonium polyacrylate solution recommended for thickening synthetic and natural latices. Can be used as supplied to produce thickened latices of a smooth consistent texture. Not sensitive to sodium, calcium, and magnesium ions. Also recommended as a pigment antimigrant. 

For more complex shampoos, including emulsions, a variety of thickeners is available besides salt, including gums, associative thickeners, synthetic polymers, and long-chain alcohols (Section II.C.2). These materials are used to attain a desired viscosity, to stabilize a product, and to attain a desirable rheological profile. Since they affect product structure, they can also affect lather. Viscosity modifiers, therefore, should be chosen to give the best mix of lather and rheological properties. 

Alcogum L-12 Alcogum L-52 Ammonium polyacrylate thickener, synthetic latex coatings Alcogum L-12... 

Synthetic lubricants are made with neopentyl glycol in the base-stock polyester (24). Excellent thermal stabiHty and viscosity control are imparted to special high performance aviation lubricants by the inclusion of polyester thickening agents made from neopentyl glycol (25,26) (see LUBRICATION AND lubricants). Neopentyl glycol is also used to manufacture polymeric plasticizers that exhibit the improved thermal, hydrolytic, and uv stabiHty necessary for use in some exterior appHcations (27). 

High Water-Base Fluids. These water-base fluids have very high fire resistance because as Httle as 5% of the fluid is combustible. Water alone, however, lacks several important quaUties as a hydrauHc fluid. The viscosity is so low that it has Httle value as a sealing fluid water has Httle or no abiHty to prevent wear or reduce friction under boundary-lubrication conditions and water cannot prevent mst. These shortcomings can be alleviated in part by use of suitable additives. Several types of high water-based fluids commercially available are soluble oils, ie, od-in-water emulsions microemulsions tme water solutions, called synthetics and thickened microemulsions. These last have viscosity and performance characteristics similar to other types of hydrauHc fluids. 

Thickeners. Thickeners are added to remover formulas to increase the viscosity which allows the remover to cling to vertical surfaces. Natural and synthetic polymers are used as thickeners. They are generally dispersed and then caused to swell by the addition of a protic solvent or by adjusting the pH of the remover. When the polymer swells, it causes the viscosity of the mixture to increase. Viscosity is controlled by the amount of thickener added. Common thickeners used in organic removers include hydroxypropylmethylceUulose [9004-65-3], hydroxypropylceUulose [9004-64-2], hydroxyethyl cellulose, and poly(acryHc acid) [9003-01-4]. Thickeners used in aqueous removers include acryHc polymers and latex-type polymers. Some thickeners are not stable in very acidic or very basic environments, so careful selection is important. 

Because the viscosity of neoprene latex at a given soHds content is less than that of natural mbber latex, thickeners are generally needed with the former. MethylceUulose and the water-soluble salts of poly(acryhc acid) are the two most commonly used thickeners. Natural and synthetic gums are also used. 

The level of technical service support provided for a given product generally tracks in large part where the suppHer considers thek product to be located within the spectmm of commodity to specialty chemicals. Technical service support levels for pure chemicals usually provided in large quantities for specific synthetic or processing needs, eg, ammonia (qv), sulfuric acid (see SuLFURic ACID AND SULFURTRIOXIDe), formaldehyde (qv), oxygen (qv), and so forth, are considerably less than for more complex materials or blends of materials provided for multistep downstream processes. Examples of the latter are many polymers, colorants, flocculants, impact modifiers, associative thickeners, etc. For the former materials, providing specifications of purity and physical properties often comprises the full extent of technical service requked or expected by customers. These materials are termed undifferentiated chemicals (9),... 

The process of textile print coloration can be divided into three steps. First, the colorant is appHed as pigment dispersion, dye dispersion, or dye solution from a vehicle caUed print paste or printing ink, containing in addition to the colorant such solutions or dispersions of chemicals as may be required by the colorant or textile substrate to improve and assist in dye solubUity, dispersion stabUity, pH, lubricity, hygroscopicity, rate of dye fixation to the substrate, and colorant-fiber bonding. The required viscosity characteristics of a print paste are achieved by addition of natural or synthetic thickening agents or by use of emulsions. 

If you combine petroleum based or synthetic based oil with a suitable thickening agent, you get grease. The thickening agent can represent between 3% and 30% of the total volume of grease. 

The polymers are of interest as water-soluble packaging films for a wide variety of domestic and industrial materials. (Additional advantages of the poly(ethylene oxide)s are that they remain dry to the feel at high humidities and may be heat sealed.) The materials are also of use in a number of solution application such as textile sizes and thickening agents. As a water-soluble film they are competitive with poly(vinyl alcohol) whereas in their solution applications they meet competition from many longer established natural and synthetic water-soluble polymers. 

Thickeners can be added to increase the viscosity of the NR adhesives. Natural materials can be used such as casein or karaya gum, but currently synthetic polymers are used (methyl cellulose and derivatives, polyacrylates). 

Ammonium sulfate is produced as a caprolactam by-product from the petrochemical industry, as a coke by-product, and synthetically through reaction of ammonia with sulfuric acid. Only the third process is covered in our discussion. The reaction between anunonia and sulfuric acid produces an ammonium sulfate solution that is continuously circulated through an evaporator to thicken the solution and to produce ammonium sulfate crystals. The crystals are separated from the liquor in a centrifuge, and the liquor is returned to the evaporator. The crystals are fed either to a fluidized bed or to a rotary drum dryer and are screened before bagging or bulk loading. 

These are generally reserved for specialist applications, and are in the main more costly than conventional soap-based greases. The most common substances used as nonsoap thickeners are silica and clays prepared in such a way that they form gels with mineral and synthetic oils. Other materials that have been used are carbon black, metal oxides and various organic compounds. 

Naturally occurring polysaccharides and their derivatives form the predominant group of water-soluble species generally used as thickeners to impart viscosity to treating fluids [1092]. Other synthetic polymers and biopolymers have found ancillary applications. Polymers increase the viscosity of the fi ac-turing fluid in comparatively small amounts. The increase in fluid viscosity of hydraulic fracturing fluids serves for improved proppant placement and fluid loss control. Table 17 summarizes polymers suitable for fracturing fluids. 

Figure 17-8. Monomers for synthetic thickeners vinyl phosphonic acid, N-vinyl-2-pyrrolidone, vinyl sulfonic acid.

Natural or synthetic, mostly low-MW molecules that reduce or suppress microbe populations in plastics. Specialised products (both organic and inorganic) which tend to be used most in plasticised materials such as PVC and polyurethanes, as well as in rubber articles. The main cause of microbial growth is the additives themselves plasticisers, starch fillers, lubricants, thickening agents and oils. 

Protective colloids can be divided into synthetic and natural materials. Table 3 classifies the pharmaceutical gums, thickeners, and other hydrophilic polymers according to their origins [72]. Protective colloids of natural origin, such as gelatin, acacia, and tragacanth, have... 

Synthetic products, e.g., polyethylene oxides(104), polyacrylates, polyacrylamides, and polyetherglycols were in competition with natural polymers like starch, guar, cellulose derivatives, alignates, carrageenan, and locust bean gum. The basic physical and structural properties of the various polysaccharide thickeners have been compiled and reviewed by numerous authors and editors(105-109). 

Polymers based on acrylic acid have gained considerable importance in recent years. Their essential chemistry is discussed in section 10.8.2 on synthetic thickeners. Copolymers of acrylic acid with acrylonitrile and methyl acrylate (10.68) contain a random distribution of cyano, ester and acidic sidechain groups [169]. 

Thickening agents can be of natural or synthetic origin. Various natural gums and starches have been used traditionally in many printing styles. The materials from which they are extracted are valuable sources of foodstuffs, so availability and cost can depend on fluctuating demand from the food industry. The properties required of an ideal thickener can be summarised as follows [352] ... 

A major drawback of synthetic thickeners when used with dyes is their sensitivity to electrolytes. Most soluble dyes behave as highly ionised electrolytes and disperse dyes contain anionic polyelectrolyte dispersing agents unless they have been formulated with nonionic systems specifically for use with acrylic thickeners. Consequently there is a loss of viscosity this can be quite pronounced although it depends on circumstances, particularly on the dye concentration. As already mentioned, this can be alleviated to some extent by copolymerisation with acrylamide during manufacture. Otherwise it is necessary to try to eliminate all electrolytes from the system or to increase the concentration of thickener. Such measures have their limitations in practice, however. Alternative synthetic thickening... 

Emulsion thickeners can be mixed with low concentrations of either natural or synthetic thickeners, especially when applying fibre-substantive dyes rather than pigments these additions act as film formers, taking the place of the binder used with pigments to increase retention of the dye by the substrate prior to fixation. 

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