Acid scavengers zinc oxide

More generally, acidic depolymerization products can be leached out of many films of paint, unless suitable pigments are incorporated. Zinc dust plus zinc oxide was the original acid scavenger. Zinc phosphate, zinc ferrite, and calcium borosilicate will each exert an anodic inhibitive function at pH values exceeding 7 while zinc chromate, zinc tetroxychromate, and strontium chromate act independently of pH value (Van Eijnsbergen, 1988). In general, the pH of aqueous paint film extracts should be between 7.5 and 8.5 and certainly not below 6 or above 10. 

Magnesium oxide is a typical acid scavenger for chlorinated mbbers. Compounds containing zinc oxide or magnesium oxide may tend to swell upon immersion in water. These inorganic salts have some water solubiHty and osmotic pressure causes the vulcanizates to imbibe water to equalize pressure (8,9). As such, vulcanizates tend to sweU more in fresh (distilled) water than in salt water. To minimize water sweU, insoluble salts such as lead oxides can be substituted. Because of the health concerns associated with lead, there is much mbber industry interest in other acid acceptors, such as synthetic... 

Special considerations calcium oxide is used as acid scavenger and desiccant zinc oxide is a curing agent in vulcanization processes calcium oxide and hydroxide are used as acid scavengers... 

Reduction of 550 (Nu = Br or Cl) with zinc powder or hydrogen in the presence of palladium on carbon and magnesium oxide as an acid scavenger provides D-malates 539 in 70-80% yields with no loss of optical purity [179]. 

Acid Scavengers. Oxidation of polymers produces organic acids. Chlorine and bromine, from catalyst residues and fiame-retardants, produce stronger acids. These can cause hydrolysis of polymers and corrosion of process equipment. Therefore, it is fairly common practice to add acid scavengers to neutralize them. These are mildly alkaline substances such as calcium and zinc stearates, hydrotalcite, hydrocalumite, and zinc oxide. 

Curatives. Consistent with dry type technology, metal oxides have three fimctions in a latex compound. Zinc oxide participates in the curing reaction. Zinc oxide is an effective acid scavenger. In applications where the substrate is not acidic, zinc oxide is not needed. Such substrates include chrysoltile asbestos gaskets or the hydraulic cement in elasticized concrete. 

Several rubbers may be crosslinked using divalent metal oxides, usually zinc oxide. There are a limited number of polymers that utilise this method, which is used with halogenated polymers such as polychloroprene [8], chloro- and bromobutyl, and chlorosulfonated polyethylene and carboxylated nitrile rubbers. The system may utilise the metal oxide alone or in combination with the organic accelerators used with sulfur-curing systems. In the case of halogenated polymers, magnesium oxide may be added to act as an acid scavenger. 

PEG 300 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy) phenol Screener titanium dioxide zinc oxide carbon black Acid scavenger hydrotalcite Fiber carbon nanotube HAS 1,3,5-triazine-2,4,6-triamine, N,N [1,2-eth-ane-diyl-bis[[[4,6-bis[butyl(1,2,6,6-pentamethyl-4-piperidinyl) amino]-1,3,5-triazine-2-yl]imino]-3,1 -propanediyl]bis[N ,N -dibutyl-N ,N -bis(1,2,2,6,6-pentamethyl-4-piperidinyl)- bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate + methyl-1,2,2,6,6-pentamethyl-4-piperidyl sebacate 2,2,6,6-tetrameth-yl-4-piperidinyl stearate reaction products of N,N -ethane-1,2-diylbis(1,3-propanediamine), cyclohexane, peroxidized... 

PEG 300 ethyl-2-cyano-3,3-diphenylacrylate (2-ethylhexyl)-2-cyano-3,3-diphenylacrylate N-(2-ethoxyphenyl)-N -(2-ethylphenyl)oxamide propanedioic acid, j(4-methoxyphenyl)-methylene]-dimethyl ester Screener carbon black, titanium dioxide, zinc oxide Acid scavenger hydrotalcite ... 

Referring to the polyolefin industry, metal stearates (especially calcium, sodium and zinc) and s)mthetic dihydrotalcites are of paramount importance as acid scavengers applied in additive formulations. A minor part is occupied by the calcium lactates/lactylates (salts of lactic acid), ZnO and other oxides. 

Zinc stearate and zinc oxide have been proposed as acid scavengers for poly(olefin)s (4). A particularly preferred acid scavenger comprises a mixture of aluminum hydroxide, zinc carbonate and zinc hydroxide (ZHT-4D, Kyowa) (5). Other acid scavengers are hydrotalcites and amorphous basic aluminum magnesium carbonates (6). 

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