Chimassorb

In the absence of the acetate Chimassorb 944 does not elute. Also, the mobile phase used here is UV transparent down to at least 220 nm, which can aid in the detection of low UV-absorbing analites. 

Figure 13.21 shows the resolution of a dozen polymer additives at very high resolution using chloroform as the mobile phase. Tinuvin 622 will elute in pure chloroform whereas Chimassorb 944 and many other hindered amine light stabilizers (HALS) will not. With the addition of 1% triethyl amine to the chloroform, however, virtually all HALS will elute. 

The photostabilizing efficiency of polymer-bound HALS in i-PP and E-P copolymers were studied and compared with commercial HALS (i.e., Tinuvin 770 and Chimassorb 944) by measuring the carbonyl index at 1720 cm. Plots of carbonyl index versus irradiation... 

For the extraction of rubber and rubber compounds a wide variety of solvents (ethyl acetate, acetone, toluene, chloroform, carbon tetrachloride, hexane) have been used [149]. Soxtec extraction has also been used for HDPE/(Tinuvin 770, Chimassorb 944) [114] and has been compared to ultrasonic extraction, room temperature diffusion, dissolution/precipitation and reflux extraction. The relatively poor performance of the Soxtec extraction (50% after 4h in DCM) as compared with the reflux extraction (95% after 2-4 h in toluene at 60 °C) was described to the large difference in temperature between the boiling solvents. Soxtec was also used to extract oil finish from synthetic polymer yam (calibration set range of 0.18-0.33 %, standard error 0.015 %) as reference data for NIRS method development [150]. 

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... 

HDPE, LDPE, PP Irgafos 168, Chimassorb 81, Irganox 1010 Acetone/heptane (1 1) trichloroethane [96]... 

LDPE Chimassorb 944 Various binary solvent mixtures [458]... 

Figure 3.15 Microwave extraction of 81 Irganox 1010 ( ), Irgafos 168 (O) and Chimassorb 0.1% (+) from powdered (20 mesh) HDPE with acetone/n-heptane (1 1 v/v). After Freitag and John [96]. From W. Freitag and O. John, Angewandte Macromoleculare Chemie, 175, 181-185 (1990). Wiley-VCH, 1990. Reproduced by permission of Wiley-VCH...

UV3346) offer superior compatibility, low volatility, excellent resistance to extraction and contribute to heat stability. The nonextractable nature of these additives makes their quantification challenging. The quantification of Chimassorb 944 in polyolefins is possible using an UV absorption method after dissolution of the polymer [596]. 

The commercial evolution of hindered amine stabilisers is best illustrated by the sequence of the monomeric Tinuvin 770, oligomeric Tinuvin 622, Chimassorb 944 and Chimassorb 119, and most recently Chimassorb 2020 (Figure 3.25) with increased control on volatility, migration, extractability and co-additive interactions [597]. The hindered amine thermal stabilisers Chimassorb 944 and Chimassorb 119, outperform Cyasorb UV3346 as to extraction resistance [565]. 

Figure 3.25 Chemical formulae of (a) Tinuvin 770, (b) Tinuvin 622, (c) Chimassorb 944, (d) Chimassorb 119 and (e) Chimassorb 2020...

Oligomeric hindered amine light stabilisers, such as Tinuvin 622 and Chimassorb 944, resist satisfactory analysis by conventional HPLC and have required direct UV spectroscopic analysis of a polyolefin extract [596], PyGC of an extract [618,648], or SEC of an extract [649]. Freitag et al. [616] determined Tinuvin 622 in LDPE, HDPE and PP by saponification of the polymer dissolution in hot toluene via addition of an... 

Figure 4.6 cSFC-FID chromatogram of a synthetic mixture of polymer additives. 1-21, Topanol OC, Tinuvin P/292/320/326 /328, Chimassorb 81, erucamide, Tinuvin 770/440, Irgafos 168, Tinuvin 144, Irganox PS 800/1076/MD 1025/245/1035/3114/PS 802/1330/1010, in this order. For conditions see Raynor etal. [343]. Reprinted with permission from Raynor etal., Analytical Chemistry, 60, 427-433 (1988). Copyright (1988) American Chemical Society... 

Monomeric HALS have been determined by HPLC [470,663]. Excellent separation was achieved for HALS-type samples (Tinuvin 770 and Chimassorb 944) with NPLC-PDA (230 nm) using an amino column with acetonitrile/water as the mobile phase RPLC using C or cyano columns was not effective [664]. 

Figure 4.13 10 jtg Chimassorb 944 (dissolved in mobile phase) analysed by use of /iHTI.CIiLSD. The xa numbers indicate... 

L. Gaiani and D. Herzfeld, Analytical Method for Chimassorb 944LD (KBC/3), Ciba-Geigy Additives, Basel (n.d.). 

Chimassorb 944 Determination in Polypropylene, High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE) by the Total Nitrogen Content Analytical Method, Code No. KC65/1, Ciba-Geigy, Basel (1980). 

Quantitative Analysis of Chimassorb 944 in Polyolefins by Ultraviolet Spectroscopy. Analytical Method No. C-260, Ciba-Geigy, Ardsley, NY (1982). 

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