Gel permeation chromatograms for

Figure 8. Gel permeation chromatograms for methylated oxidation products from Brazil Block Seam sporinite and vitrinite and the Upper Elkhorn Seam inertinite.

Figure 6. Gel permeation chromatograms for PFAP(II) (with 0 and 1 wt % bis(8-oxyquinolate)zinc(II)) aged at 177° C...

Figure 11. Effect of monomer addition method on gel permeation chromatogram for poly(propylene ether) trials prepared using zinc hexacyanocobaltate complex catalyst...

Table 9,4 Data for the Analysis of the Gel Permeation Chromatogram of a Poly disperse Polymer Used in Example 9.7...

Gel permeation chromatograms actually give information about molecular size. For any polymer, size is determined hy a number of factors. These include not only molar mass but also temperature and thermodynamic quality of the solvent. Hence the relationship between size and molar mass is unique for each particular polymer-solvent combination, and we caimot assume that because two peaks of different polymers, even in the same solvent at the same temperature, have the same elution volume their molecules have the same molar mass. 

The possibility exists that the acid used in hydrolysis could catalyze the hydrolysis of the succinic ester group in the middle of the telechelomer itself. Even though NMR ( H and C) cannot easily eliminate this possibility, we have evidence that such a hydrolysis did not take place. For instance, hydrolysis should result in the formation of poly(pivalolactone) which is insoluble both in methylene chloride and water, but no insolubles were evident. Also, the Gel Permeation Chromatograms do not show impurities in the product. 

A TEA/DIBAH mixture can be added to cold (-78°C) monomer until the stable colored complex forms. The purification reaction is then allowed to proceed for 60 minutes at room temperature. This procedure allows for removal of impurities without reduction of the ester. Significantly narrower gel permeation chromatograms (Mw/Mn <1.25) of poly(t-butyl methacrylate) are obtained when the samples are prepared from TEA/DIBAH purified monomer. 

Fig. 55. Gel-permeation chromatogram(GPC) of a microgel sample of Mw = 10X106 g/mol obtained in the anionic polymerization of EDMA in toluene. Microgel concentration = 1 g/L solvent = butyl acetate elution temperature = 70 °C is the weight-average molar mass of linear polystyrene used for comparison. [Reproduced from Ref. 256 with permission, Huthig Wepf Publ., Zug, Switzerland].

Figure 5.2. Gel permeation chromatogram (GPC) of the liquid silicon precursor for Si film formation for (a) cyclopentasilane (CPS) and (b) UV-irradiated CPS, both of which were diluted with toluene (1 vol.%) before GPC measurements. The UV-irradiation conditions were 405 nm, 100mW/cm2, and a 10-min irradiation for 1cm3 of CPS. The broad peak around Mw = 2600 corresponds to polysilanes of various molecular weights, as a result of the photo-induced polymerization of CPS. [Reproduced with permission from Ref. 10. Copyright 2006 Nature Publishing Group.]...

An example for the synthesis of poly(2,6-dimethyl-l,4-phenylene oxide) - aromatic poly(ether-sulfone) - poly(2,6-dimethyl-1,4-pheny-lene oxide) ABA triblock copolymer is presented in Scheme 6. Quantitative etherification of the two polymer chain ends has been accomplished under mild reaction conditions detailed elsewhere(11). Figure 4 presents the 200 MHz Ir-NMR spectra of the co-(2,6-dimethyl-phenol) poly(2,6-dimethyl-l,4-phenylene oxide), of the 01, w-di(chloroally) aromatic polyether sulfone and of the obtained ABA triblock copolymers as convincing evidence for the quantitative reaction of the parent pol3rmers chain ends. Additional evidence for the very clean synthetic procedure comes from the gel permeation chromatograms of the two starting oligomers and of the obtained ABA triblock copolymer presented in Figure 5. 

Gel permeation chromatograms were generated from a Waters Associates, Inc. GPC equipped with a refractive index detector. The following operating conditions were employed mobile phase, THF flow rate 1 ml/min., columns ICP, 10, 500, 100 A . Sample concentrations were prepared at 0.2% (w/w) a 100 microliter aliquot was used for molecular weight analysis. Standard polystyrene samples (Polymer Laboratories, Inc.) were used to create a calibration curve. 

Figure 1. Gel permeation chromatograms of phenolysis reaction mixtures— Phenol mixtures reacted for (A) 10 min, (B) 60 min, (C) 120 min, and (D) 240 min.

The gel permeation chromatograms of MRS are shown in Figure 9, where peaks 1 and 2 represent the azide compound and the main component of poly(p-vinyl phenol), respectively. Peak 3 corresponds to a primary amine, which is one of the exposure-induced reaction products from the azide compound (14). Peak 4 indicates the same exposure-induced high molecular weight components as for EP. 

Polymerizations were conducted in 250 x 20 mm test tubes fitted with rubber septum caps. Typically, the covered tubes were cooled to the desired temperature, the solvent and monomer were charged, and the temperature allowed to equilibrate. At this time a suitable volume of a solution of Lewis add coinitiator was introduced. The polymerization was terminated by addition of 1-2 ml of methanol. The polymer was recovered by allowing the solvent and unreacted monomer to evaporate, and rinsing with methanol to remove coinitiator residues. To insure that no polymer was lost by rinsing with methanol the gel permeation chromatograms of a number of samples were obtained before and after rinsing. They were found to be identical. The polymer was dried for at least 48 hrs at room temperature under vacuum. 

Solubility in Methylene Chloride. The methods described above can show the presence of blocks of DMP and blocks of DPP units, but they do not distinguish between block copolymers and blends of homopolymers. Gel permeation chromatograms of the copolymers are sharp and symmetrical, indicating that they are indeed copolymers rather than blends, but this alone is not conclusive as blends of the homopolymers do not produce binodal or badly skewed curves under the conditions used unless the two polymers differ considerably in molecular weight. A partial answer to this question is provided by the solubility behavior in methylene chloride. Dimethylphenol homopolymer dissolves readily in methylene chloride but precipitates quantitatively on standing for a short... 

Figure 4.3. Gel permeation chromatograms of humic acids isolated from a soil either unamended (A) or amended with 25tha 1yr 1 of cattle manure for 4 years (B) and 25, 50, and 100tha 1yr 1 of sewage sludge for 4 years (C, D, and E, respectively). Reprinted from Piccolo, A., Zaccheo, E, and Genevini, P. G. (1992). Chemical characterization of humic substances extracted from organic-waste-amended soils. Bioresource Technol. 40, 275-282, with permission from Elsevier.

Figure 6.5 Gel permeation chromatogram of isoamylase-treated potato amylose on Toyopearl HW-75F. Potato amylose (50 mg in 5 ml ) was incubated at 45°C with 5.5 U of Pseudomonas isoamylase in 20 mM acetate buffer (pH 3.5) for 2.5 h. An aliquot (1 ml.) was applied to the column — and , carbohydrate concentration and beta-amylolysis limit, respectively, of the isoamylase-treated amylose ., carbohydrate...

Molecular-Weight Distribution. The solid line in Figure 1 shows a typical gel-permeation-chromatogram trace for an unfractionated neoprene-g-PTHF (Polymer 1, Table I) that was soluble in THF. The... 

Figure 6.2 (a) Average DP and polydispersity value versus conversion for bulk living polymerization of styrene by RAFT (b) corresponding gel permeation chromatogram. Reaction conditions T = 80 °C initiator, AIBN RAFT agent, Z = Ph, R = CH(CH3)Ph (cf. Scheme 6.4) styrene RAFT agent initiator = 600 4 1 (w/w)... 

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