Toluene, precipitation

PP/Uvasil 299 fibres were analysed by 1II NMR after dissolution (toluene)/precipitation (methanol) and PP/Uvasil 299 pellets after reflux extraction with precipitation (methanol) of the oligomers [619]. The dried extracts were redissolved in CDCI3, containing the DMP internal standard. The method allows quantification of the high-MW HALS at very low levels (0.044 0.001 %). 

Dissolution (toluene)/precipitation (methanol) of EPS beads (atactic PS foams with ca. 2wt.% HBCD and BaSCL) with TLC separation and IR identification allowed detection of hexabromocyclododecane for quantification XRF analysis (Br) was used [629]. Disso-lution/precipitation of PS/lubricants with evaporation to dryness and redissolution was followed by FT1R analysis [106],... 

In a comparative qualitative study El Mansouri et al. [632] examined dissolution/precipitation and Soxhlet extraction of phosphorous antioxidants in PP. The dissolution (refluxing toluene)/precipitation... 

Howard [772] has been amongst the first to show the usefulness of conventional SEC for polymer/additive systems. Coupek el al. [773] have also reported results with this technique in an early stage their work was limited to synthetic mixtures of additives. The use of open-column SEC in the analysis of plastics additives has been reported [774], Qualitative analysis of additives has been performed by stopped-flow SEC with IR detection [775]. Polypropylene oligomers were isolated from a PP/(Irganox 1010, Irgafos 168, DBS) matrix by dissolution (toluene)/precipitation (methanol) and Soxhlet... 

The boundary for toluene precipitation shows that there are no toluene-insoluble materials in this particular resid because there is no material of sufficiently high polarity or molecular weight to be insoluble in toluene. If there were,... 

No pure tellurium derivatives were obtained when the sodium salts of maleic, fumaric, formic, isophthalic, or terephthalic acids were shaken with diaryl tellurium dichlorides2. Diorgano tellurium dichlorides stirred with silver carboxylates in dioxane, acetone, chloroform, benzene, or toluene precipitated silver chloride. Evaporation of the filtrate yielded diorgano tellurium dicarboxylates. 

Polychloroprene (Neoprene W or AC Soft, E. I. duPont de Nemours and Co.) was dissolved in toluene, precipitated in methanol, and dried in a vacuum oven at room temperature. This procedure was repeated three times. The polymer was used immediately after the last precipitation. Neoprene W and Neoprene AC Soft have Mns of 180,000 and 230,000, respectively, and allylic chloride contents of 1.45 and 0.77 mol%, respectively. The Mns were determined by osmometry, and mol% allylic chloride are based on an IR measurement of the 1,2-addition-product band of polychloroprene at 921 cm"1 (5). PTHF used for DTA and stress-strain measurements had TvTn = 95,000. 

The coil-globule transition can also be observed by PL (from changes in the IMM of the polymer), when polymers are precipitated in organic solvents. These data were obtained for PMMA in toluene precipitated with octane or other non-solvents. Figure 9 shows the dependence Tw on the concentration of octane used as the precipitant for PMMA fractions of various molecular weights. Naturally, for PMMA in... 

Figure 11.21 shows the CP/MAS spectra of an annealed s-PP sample [33]. This sample was hot washed with toluene, precipitated with methanol. 

With loose structures of linear molecules the exponent for instance to cellulose nitrate in acetone, precipitated by water, to Polyvinyl acetate in toluene, precipitated by a methanol-water mixture-, and to the methyles-ters of polymethacrylic acid in benzene, precipitated by cyclohexane With compact spherical particles we must expect n-values in the neighbourhood of 2/3, since in this case only the outer surface of the particles is subject to the action of the medium. Examples can be found in some proteins. Finally, if the long-chain molecule shows a pronounced ramification or if the randomly kinked structure is comparatively close-packed, n may assume values between 0.7 and 1. This is shown for instance, by branched polystryrene h by acetyl-starch and by glycogene An accurate check on the value of n, however, is usually impossible. Husemann s experiments with glycogene, for instance, can be equally well described by n = 2/3 as by n — J (Fig. 5). This is due to the fact that the value of P in this method is not unlimited. In practice the upper limit of the molecular weight lies in the neighbourhood of 5.10, the lower limit lies in the further to be noted that the constant b in equation... 

After filtration and washing with EtOH and water, 500 ppm Ru were found in the polymer. Dissolving the polymer in toluene, precipitation into EtOH and drying gave still a Ru-content of 430 ppm. Muhlebach, A. unpublished results. 

Monomers C, D, and E were prepared in a similar way. Monomer F was prepared by the procedure of Martin et al. This was because of extensive dehydrochlorination and polymerization in the presence of DMF. Dichloromaleic anhydride (0.01 mole) and diamine (0.005 mole) were separately dissolved in glacial acetic acid at room temperature, and the solution was mixed and gently refluxed for 2 h. After cooling, bisimide was precipitated in excess of water. The precipitates were collected by filtration and washed with water till free from acid and dried at 80°C. The product was dissolved in toluene, precipitated in hexane, and subsequently dried in a vacuum oven. 

Poly(styrene-co-acrylonitrile) Chromatography 2,2,4-Trimethylpentane/toluene Precipitation ehromatogr. 1072... 

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