Polygard, determination

Phenolic antioxidants in rubber extracts were determined indirectly photometrically after reaction with Fe(III) salts which form a red Fe(II)-dipyridyl compound. The method was applicable to Vulkanox BKF and Vulkanox KB [52]. Similarly, aromatic amines (Vulkanox PBN, 4020, DDA, 4010 NA) were determined photometrically after coupling with Echtrotsalz GG (4-nitrobenzdiazonium fluoroborate). For qualitative analysis of vulcanisation accelerators in extracts of rubbers and elastomers colour reactions with dithio-carbamates (for Vulkacit P, ZP, L, LDA, LDB, WL), thiuram derivatives (for Vulkacit I), zinc 2-mercaptobenzthiazol (for Vulkacit ZM, DM, F, AZ, CZ, MOZ, DZ) and hexamethylene tetramine (for Vulkacit H30), were mentioned as well as PC and TLC analyses (according to DIN 53622) followed by IR identification [52]. 8-Hydroquinoline extraction of interference ions and alizarin-La3+ complexation were utilised for the spectrophotometric determination of fluorine in silica used as an antistatic agent in PE [74], Also Polygard (trisnonylphenylphosphite) in styrene-butadienes has been determined by colorimetric methods [75,76], Most procedures are fairly dated for more detailed descriptions see references [25,42,44],... 

The widely used method for the determination of this stabiliser is based on the determination of phosphorus. This involves a tedious preliminary digestion with nitric and perchloric acids. Kellum [84] has described a colorimetric method for determining Polygard based on hydrolysis to nonyl phenol, followed by coupfing with p-nitro benzene-diazonium fluoroborate and colorimetric estimation at 550 nm ... 

Various other phenoUc antioxidants produced dyes under these conditions, namely, Wingstay S, Agerite Superlite and Nevastain A. The procedure was applied to the determination of Polygard in dry rubber and latexes and the results obtained showed good precision. Good agreement was obtained between this procedure and direct determinations of phosphorus by elemental analysis. 

Brandt [85] has described an alternate method for the determination of Polygard in styrene-butadiene rubber which utilises the bathochromic shift in the spectrum of phenols resulting from the formation of phenolate ions in alkaline solution. 

Crompton [59] has described a simple direct thin-layer method for the determination of UV 531 ultraviolet stabiliser in hot toluene extracts of HDPE. Interference was encountered from a number of additives, namely, dilauryl thiodipropionate, lonox 330, lonol CP, Topanol CA, Santonox R and Polygard. 

An early report on the direct determination of stabilisers in pressed polymer films by UV spectrophotometry is due to Drushel et al [13]. The determination of a variety of additives (Santonox R, lonol, lonox 330, CAO-5, CAO-6, DPPD, Polygard, Topanol) in the 0.002-1.0% range in ten mils thick... 

Similar effects to these were also observed with polystyrene containing other ultraviolet absorbing additives. Thus, the influence of a mixture of 0.4% w/w tris-(nonylated phenyl phosphite (Polygard) and 0.2% w/w 2,6-di-tert-butyl-p-cresol (lonol CP) on the determination of styrene monomer is shown in Table 1.8. 

Table 1.8 - Influence of Polygard/Ionol CP Mixture on Determination of Styrene Monomer by Direct Ultraviolet and by Distillation/Ultraviolet Methods...

Nawakowski has described a colorimetric method for determining Polygard (trisnonylphenylphosphite) based on hydrolysis to nonyl phenol, followed by coupling with p-nitro benzene-diazonium fluoroborate and colorimetric estimation at 550 nm. 

Table 2.3 - Determination of Polygard comparison of ultraviolet with perchloric acid methods... 

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