Gums or polymers

Since the liquors come from gas scrubbing and have been settled for a long time, the SS are almost colloidal and do not interfere with treatment. Solids are not usually measured and the few recorded values range from 0.2 to 0.5 g I (except when gums are present). In addition, it is not easy to measure them. 

Total HC content may vary from 0.05 to 4%. It may therefore be high enough to cause volatile HC to evaporate which is a hazard during air stripping. Anticipated concentrations of less than 0.05 g l are in fact seldom achieved. 

IR analysis of HC often shows a considerable fraction of polar compounds. It is sometimes of the same order of magnitude as the nonpolar HC fraction itself. For example 12 g H before Florisil, 7.5 after. 

Just one of the drawbacks of these products which can be very troublesome is that they are deposited on pH meter probes and on packing. They can have two origins  

The precipitated sulfur is colloidal and gives a yellowish color to the deposits. The reaction can also occur without air oxidation of spent caustic if the caustic already contains a significant fraction of thiosulfates. This is often the true for SC caustic but is undetected by analysis. 

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Two solutions are possible to remove the HC in emulsion or prevent gum or polymer formation. 

A hydraulic fracturing fluid containing guar gum or other natural polymers can be stabilized against bacterial attack by adding heterocyclic sulfur... 

Among the oxidative breakers, alkali, metal hypochlorites, and inorganic and organic peroxides have been described in literature. These materials degrade the polymer chains by oxidative mechanisms. Carboxymethylcellulose, guar gum, or partially hydrolyzed polyacrylamides were used for testing a series of oxidative gel breakers in a laboratory study [180]. 

An aqueous base is the least expensive vehicle and poses no toxicity problems. A solution of the drug in water or water and cosolvent is made. Glycerin, glycols, natural and synthetic gums, and/or polymers are used to increase viscosity, cohesiveness, and plasticity. To overcome syneresis, or water separation in the gel, a common problem with aqueous bases, one can use absorbing materials such as microcrystalline cellulose, kaolin, colloidal silicon dioxide, starch, etc. 

Sizing. Material used to. increase or improve the stiffness, strength, smoothness, or weight of fibers, yarns, fabrics, paper, leather, and the like. Examples are starch, oils, gums, waxes, polymers, and silicones. 

Different gum bases are used for chewing gum and bubble gum. Bubble gum base contains either higher levels of polymers or polymers with a higher molecular weight. Both of these foundations make the gum base more extensile and hence able to form bubbles. 

In some circumstances the oil drops actually adhere to each other and are not readily redispersed. This occurs when the emulsifier is polymeric (e.g., protein, gum, or polyoxyethylene derivative). By one mechanism, different segments of a polymer molecule adsorb to the surfaces of two drops, thus forming a bridge that holds them together. Another mechanism obtains when polar parts of two polymer molecules (adsorbed to separate drops) approach each other and intertwine. This tangle, say of long polyoxyethylene chains, then holds the drops in proximity,... 

Adsorption of a non-ionic polymer (gum or cellulosic) or surfactant (polysorbate 80) of sufficient chain length creates steric hindrance and prevents adjacent suspended particles from coming close enough to join each other. Steric stabilization has the advantage over electrostatic stabilization in that it is relatively insensitive to the presence of electrolyte in the aqueous vehicle. 

Softgel delivery systems can also incorporate phospholipids or polymers or natural gums to entrap the drug active in the gelatin layer with an outer coating to give desired delayed/controlled-release effects. 

Polymeric phases (25 gum or greater thickness) Here a di- or trichlorosilane is used in the presence of water vapour which provokes a polymerization of the reactant in solution prior to deposit and bonding with the silica. A reticulated polymer layer is obtained. At the molecular scale the final framework of the coating is difficult to imagine it is mono- or multilayer. 

Natural polymers such as albumin, gelatin, fish glue, shellac, and gum arabic received attention up to the early 1900 s, after which time other materials such as bichromate, diazo compounds, iron salts, and silver halides were added to resins in order to hasten or accomplish their crosslinking. These systems were neither photopolymerization nor photocrosslinkable polymers. Instead, the added second component, when excited by light, produced a species which itself caused the formation of radical sites on a prepolymer or polymer chain which then led to cross-linking. 

In this context, addition of surfactants or polymers such as gelatins, alcohols and gums can avoid particle aggregation and sorption on the... 

These natural homo- and copolymers (such as starch and cellulose) are composed of sugar residues and/or their derivatives. The names carbohydrate polymer and polysaccharide refer to the chemical structure. Carbohydrate polymers are also designated as gum or hydrocolloid, which refers to the property that these polysaccharides hydrate in hot or cold water to form viscous solutions or dispersions at low concentration. The gums/hydrocolloids may be harvested from nature or obtained by the chemical modification of native polysaccharides. 

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