Polymers oxygen scavengers

In addition to the normal problems of completely dissolving particles of water-thickening polymers, xanthan gum contains insoluble residues which decrease polymer injectivity. Various methods of reducing insolubles content and improving xanthan solution injectivity are available (80—87). None appears economically viable. Oxygen scavengers (88) and bactericides (77,89) are commonly used to stabili2e injected polyacrylamide and xanthan gum solutions (90—102). 

When chemical treatment for both HW heating and LP steam heating systems is generally some combination of a nitrite/borate/silicate/ molybdate formulation, usually with TTA/polymer or phosphate but having no specific oxygen-scavenging capability. 

NOTE This chart assumes oxygen scavenger, polymer, and other necessary water chemistry controls are in place. If the FW is fully softened, there is no benefit in using this program. Employ a phosphate-cycle or alternative program. 

NOTE This chart assumes oxygen scavenger, polymer, and other necessary water chemistry controls are in place. 

Alkalinity boosters, which are vitally necessary to enable carbonate, phosphate, balanced polymer (polymer plus phosphate or chelant), and some other program types to function, are perhaps best described as conjunctional treatments, whereas oxygen scavengers, antifoams, and condensate line corrosion inhibitors are adjuncts. Programs such as phosphate-tannin mixtures are sometimes described as adjunct treatments. The chemistries and applications of various types of conjunctional treatments and adjuncts are described in this chapter. 

Similarly, when catalyzed the reaction rate decreases significantly as a function of pH level. The optimum reaction pH level is approximately 9.5 to 10.5. Iron, and especially copper, in the boiler may act as adventitious catalysts. However, as metal transport polymers are frequently employed, iron, copper, or cobalt may be transported away from contact with sulfite, and thus are not available for catalysis. (This may be a serious problem in high-pressure units employing combinations of organic oxygen scavengers and metal ion catalysts.)... 

Novel oxygen scavengers and polymer-based deposit control programs hardly figure in the operation of these large boilers because the treatment regimen is often simply hydrazine and ammonia. 

Amines can be blended into multifunctional product formulations containing alkali, polymer, and phosphate and where sulfite- or hydrazine-based oxygen scavengers are part of the formula, but not where tannins are employed. Amines must be fed separately from tannins. 

Autoxidation can lead to deterioration of food, drugs, cosmetics, or polymers, and inhibition of this reaction is therefore an important technical issue. The most important classes of autoxidation inhibitors are radical scavengers (phenols, sterically demanding amines [65, 66]), oxygen scavengers (e.g. ascorbic acid), UV-light absorbers, and chelators such as EDTA (to stabilize high oxidation states of metals and thereby suppress the metal-catalyzed conversion of peroxides to alkoxyl radicals) [67]. 

The oxygen scavenging polymer system consists of an oxidizable resin, ethylene methyl acrylate cyclohexene methyl acrylate (EMCM) and a masterbatch containing a photoinitiator and a cobalt... 

The most obvious benefit of using an oxygen scavenging film versus a sachet is that it does not appear as a foreign object. Moreover, the polymer-based film, unlike the metal-based scavenger, is also completely independent of moisture and has no effect on metal detection systems. 

Studies show that Nylon-6/clay nanocomposites can achieve an OTR (oxygen transmission rate) almost four times lower than unfilled nylon-6 [32]. In the case of Honeywell Aegis OX, the nanoclay layers act as a trap to retain the active oxygen scavengers in the polymer while reducing OTR 100-fold [291]. Imperm , produced by Mitsubishi Gas Chemical Company, has similar results when added to a multilayer PET structure. Imperm s oxygen barrier is two times the standard Nylon MXD6 and its carbon... 

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