Organic phosphites

Both thermooxidation and photooxidation of polyolefins can be prevented by using the same antioxidants as those employed for the stabilization of polypropylene, ie, alkylated phenols, polyphenols, thioesters, and organic phosphites in the amount of 0.2—0.5% (22,25). 

Because nitrile rubber is an unsaturated copolymer it is sensitive to oxidative attack and addition of an antioxidant is necessary. The most common practice is to add an emulsion or dispersion of antioxidant or stabilizer to the latex before coagulation. This is sometimes done batchwise to the latex in the blend tank, and sometimes is added continuously to the latex as it is pumped toward further processing. PhenoHc, amine, and organic phosphite materials are used. Examples are di-Z fZ-butylcatechol, octylated diphenylamine, and tris(nonylphenyl) phosphite [26523-78-4]. All are meant to protect the product from oxidation during drying at elevated temperature and during storage until final use. Most mbber processors add additional antioxidant to their compounds when the NBR is mixed with fillers and curatives in order to extend the life of the final mbber part. 

Sulfides orthio derivatives Metallic derivatives of thio ethers and disulfides, usually mixed with organic phosphite esters long-chain alkyl thienyl ketones Lubricating oils boiler water... 

Organic phosphites POR(OR )OR where R=Ci—C30 represents aliphatic, cycloaliphatic, or aromatic radical, are also able of inhibiting the thermal destruction of polyolefin [19]. Of light stabilizers, benzo-phenone derivatives have the ability for inhibiting thermal destruction of polyolefins, too. 

Organic phosphates Organic phosphites Organic phosphonates... 

Organic phosphites are used in a variety of ways as solvents and as intermediates in synthesis. Two series of compounds having the formulas (R0)2P(0)H and (RO)3P are known, and their structures can be shown as follows. 

Nascimento, C. R. and Dias, M. L., Poly(ethylene terephthalate) recycling with organic phosphites - I. Increase in molecular weight,. /. Polym. Eng., 20, 143 (2000). 

Tris(acetylacetonato) chromium has been shown to be of interest as a smoke retarder for poly(vinyl chloride)5 and it augments the inhibition of polyene oxidation by organic phosphites.29... 

The selected organic salts of Ba, Cd, Zn, Sn, Pb, and Ca perform with varying degrees of acceptability. Barium-cadmium and barium-cadmium-zinc are the most widely used tin mercaptides and organotin complexes are utilized where ultimate clarity is required lead salts dominate in electrical applications, and calcium-zinc combinations have been traditionally used when FDA approval is necessary. Organic phosphites are also utilized as so-called chelators, complexing the half-chloride salt... 

Relatively high concentration levels of UV absorbers, 0.25-0.5 %, are used in plastics containing conventional basic stabilization (i.e. a combination of a phenolic antioxidant, organic phosphite and calcium stearate) (Gugumus, 1990). Combinations of UV absorbers with HAS are beneficial in pigmented polyolefins. 

Bauer I, Habicher W D, Korner S and Al-Malaika S (1997) Antioxidant interaction between organic phosphites and hindered amine light stabilizers effect during photooxidation of polypropylene, Folym Degrad Stab 55>217-224. 

Flexible PVC (Table 15.6) is made by polymerizing at 40-55°C and then compounding with 20-80 PHR (parts per hundred of resin) of dioctyl phthalate and/or other monomeric liquid plasticizers (e.g., dioctyl adipate for low-temperature flexibility, oligomeric polyesters for permanence, organic phosphates for flame-retardance), plus a synergistic stabilizer system usually composed of barium or calcium soap, zinc soap, epoxidized fatty ester, and organic phosphite. 

Organic phosphites are relatively important because they have useful properties and function as reactive intermediates for preparing numerous other compounds. The organic phosphites have the general formulas (RO)2P(0)H and (RO)3P and the structures of these types of compounds are... 

Norman L. Allinger and Phillip Bowen (The University of Georgia) Molecular Mechanics Parameterization of Organic Phosphites. ... 

Film Preparation. The PVC homc olymer and the copolymers were reprecipitated from THF solution with meUianol. Experimental compositions were made up containing 100 parts PVC homc olymer or PVC copolsrmer, 3 parts Ferro 75-001 (Ba-Cd stabilizer), 1 part Mark C (organic phosphite chelator), and 4 parts Drapex 3.2 (Epoxy plastici-... 

If one desires to optimize the yield of mercaptan, there needs to be a large excess of H2S used in the process. Acetophenone and its derivatives such as 2,2 -diethoxyacetophenone and benzoin ethyl ether, and organic phosphites are a few photoinitiators that... 

Methods are being elaborated for synthesizing multifunctional stabilizers comprising in one molecule the fragments of either hindered amine or a nitroxyl radical and UV absorber, organic phosphite, hindered phenol, thioether, metal derivative, especially those of nickel, etc. 

Aromatic amines are not able to deactivate ROOH. The effect may be reached in PO, PUR or diene based elastomers with heterosynergistic combinations of amines with secondary AO like organic phosphites or sulfides. 

Artificial weathering of plasticized PVC 1 mm (40 mil) thick. Plasticizer 50 phr OOP. Stabilizer systems Curve 1, no stabilizer Curve 2, ESO 3 phr, Ba/Cd/Zn/organic phosphite 2.25 phr Curve 3, same as for Curve 2 plus 1 phr of 2-hydroxy-4-raethoxybenzophenone UV absorber. Weathering Carbon Arc Weather-Ometer, black panel temperature 145 °F (63 °C), water spray 18 min every 2 h (52). 

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