Antioxidants tris nonylphenyl phosphite

Peroxide-decomposing antioxidants destroy hydroperoxides, the sources of free radicals in polymers. Phosphites and thioesters such as tris(nonylphenyl) phosphite, distearyl pentaerythritol diphosphite, and dialkyl thiodipropionates are examples of peroxide-decomposing antioxidants. 

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. 

Applications Extraction is typically accomplished by refluxing the polymer in an appropriate solvent for l-48h [84,199]. In many cases, ultrasonic exposure reduces the extraction time [90,200], According to Table 3.5 there are several reports of US extraction from polymers. Ultrasonic extraction has been used for HDPE/(BHT, Irganox antioxidants, Isonox, Cyasorb, Am 340, MD 1024, Irgafos 168) [56], LDPE/Chimassorb 81 [201], SBR/tri(nonylphenyl) phosphite [200], HDPE/(Tinuvin 770, Chimassorb 944) [114], etc. Nielson [90] compared the recoveries obtained for a variety of analytes from PP, LDPE and HDPE with Soxhlet, ultrasonic bath and microwave oven. For all samples, the ultrasonic extraction could be achieved within 1 h. For LDPE and PP most compounds (except Irganox 1010) were extracted within 10 min. Further experiments by Nielson [56] on extraction from HDPE confirmed these results. Where phosphite antioxidants (such as Irgafos 168) are present the use of the solvent mixture DCM-cyclohexane was preferred as it prevented hydrolysis of the phosphite by extraction solvents such as alcohols [56]. Similarly, phosphite esters also undergo hydrolysis... 

The specialists in rubber additives are distinctly different from the specialists in additives for plastics, even though the same products are sometimes used in both industries blowing agents (azodicarboamide), phenol antioxidants (BHT, 2246), phosphites (tris-nonylphenyl phosphite). In the first place, additives for elastomers, unlike those which might come into contact with foodstuffs, do not require official approval, which... 

A mixture of monomers and TDM is added with mixing to the polybutadiene substrate for 5 hrs in the presence of the initiator system and the emulsifier. After polymerization, latexes were stabilized by adding 2,6-di-ter -butyl-p-cresol (DBPC) or tri(nonylphenyl) phosphite (TNPP) as antioxidants. They were then coagulated with a calcium chloride solution and finally dried at 50°C for 15 hrs. 

Typical processing stabilizers for polypropylene and butylated hydroxy-toluene (BHT) as the primary antioxidant and phosphates and phosphonates as secondary antioxidants. Examples of the latter that are commonly used are tetrakis-(2,4-di-terr-butyl-phenyl)-4-4 -bisphenylylenediphosphonite, distearyl-pentaerythrityl-diphosphonite, tris-(nonylphenyl)-phosphite, tris-(2,4-di-teft-butyl-phenyl)-phosphite and bis(2,4-di-ferr-butyl-phenyl)- pentaerythrityl-diphosphite. In commercial polypropylenes, phosphorous compounds are always used together with a sterically hindered phenol. The compounds are commonly added in concentrations between 0.05 and 0.25%. 

The performance of a primary antioxidant can be improved by the use of a secondary antioxidant. Secondary antioxidants or peroxide decomposers do not act as radical scavengers but undergo redox reactions with hydroperoxides to form nonradical stable products (Fig. 2). This class of antioxidants (Table 3) includes phosphites such as tris(nonylphenyl)phosphite (PS-1) and thiosynergists or thioesters such as dilauryl... 

Pentaerythrltyl tetrakis [3-(3,5 -dl-t-butyl-4-hydroxyphenyl) propionate] Poly (dipropyleneglycol) phenyl phosphite Seenox DL Seenox DS Thiodiethybne bis (3,5-di-t-butyl-4-hydroxy) hydrocinnamate, Tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, Tris (nonylphenyl) phosphite, Weston TDP Weston TNPP antioxidant, PU polyols Naugard 445 antioxidant, PVB BNX MD-1024 antioxidant, PVC... 

Tridecyl phosphite 2,4,5-Trihydroxybutyrophenone Tris (2,4-di-t-butylphenyl) phosphite 1,1,3-Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane Tris (nonylphenyl) phosphite antioxidant, polyols... 

Tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate Tris (2,4-di-t-butylphenyl) phosphite Tris (dipropyleneglycol) phosphite 1,1,3-Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane Tris (nonylphenyl) phosphite antioxidant, pulp/paper Calcium disodium EDTA antioxidant, PVC 1,2-Bis (3,5-di-t-butyM-hydroxyhydrocinnamoyl) hydrazine Bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite 4,4 -Bis (0,0-dimethylbenzyl) diphenylamine 4,4 -Butylidenebis (6-t-butyl-m-cresol) p-Cresol/dicyclopentadiene butylated reaction product... 

Tris (nonylphenyl) phosphite antioxidant, PVC polymers Octyl diphenyl phosphite antioxidant, radiation sickness Thioctic acid antioxidant, recreational... 

Organic Phosphites. These are also often used. When they are used to supplement the hindered phenol primary antioxidant, they are considered nonradical peroxide decomposers. On the other hand, in many polymers, they may he used as the primary anti-oxidanL presumably both to prevent the formation of peroxide and to decompose any peroxide that does form. The most popular is tris(nonylphenyl) phosphite, but many others are also used. 

Phosphorus acid esters are very well-known antioxidants, mainly for polyolefins, but as mentioned previously, they also find application as PVC stabilizers (see Section 10.2.2). Good examples are tri(nonylphenyl) phosphite (Santowhite TNPP). 

The same structure fBciency relationship is also observed in the phosphorus-containing antioxidant group. Thus it has been established that stabilization systems with tris(nonylphenyl) phosphite and distearyl pentaerythritol diphosphite are significantly inferior to systems containing tris(2,6-di-tert-butylphenyl) phosphite and tetra-kis(2,4-di-tert-butylphenyl)-4,4 -diphenylene-bisphosphite [10]. 

One likely source of nonylphenol is the use of tris(nonylphenyl)phosphite (TNPP) as a stabilizer and antioxidant in food contact plastics. 

Most conventional antioxidants either trap the oxy radicals or decompose the hydroperoxides (COOH). Radical traps forperoxy and alkoxy radicals are the familiar amines and phenols. Examples of peroxide decomposing antioxidants are phosphate stabilizers such as tris(nonylphenyl) phosphite (Naugard P), thioester stabilizers such as dilauryl thiodiproprionate (DLTDT), and dithiocarbamate stabilizers such as nickel di-n-butyldithiocarbamate (Naugard NBC). 

Phosphites Tris-(p-nonylphenyl) phosphite (X) No Widely used in conjunction with conventional stabilisers (q.v.) in PVC. Some types appear to be useful heat and light stabilisers in polyolefins. Function primarily as peroxide decomposers rather than chain-breaking antioxidants. 

Tris-4-nonylphenyl phosphite is an important additive useful as an antioxidant for rubber and in lubricating oil as for example in polyesters derived from neopentyl polyol (ref.33) in conjunction with a (Cg or Cg) dialkyidiphenylamine. It has found a use as an additive in radiation-resistant polypropene compositions (ref. 34). 

In addition to the use of the above phenolic and amine type antioxidants, peroxide decomposers are used to harmlessly decompose the peroxides, which otherwise could decompose to give free radical propagating species, e.g., R-0 or H-0 . Examples of such peroxide decomposers, which act synergisticaUy with the phenolic or amine antioxidants, are dilauryl- 3, 3-thiodiproprionate and tris(p-nonylphenyl)phosphite. These and others are also listed in Table 4.10, with their chemical structures being listed in Table 4.11. We note that some of the peroxide decomposers are also accelerators for sulfur vulcanization. 

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