Poly quantitative analysis

Applications Van der Maeden et al. [646] first used GE-HPLC for the qualitative and quantitative analysis of oligomeric mixtures, such as low-MW resins (epoxy up to 16-mer, o-cresol novolak up to 16-mer, p-cresol novolak up to 13-mer), prepolymers (poly-(2,6-diphenyl-p-phenylene oxide) up to 20-mer), PET (up to 14-mer) and ethoxylated octaphenol surfactants (up to 19-mer). In many GE-HPLC separations of oligomeric mixtures, a compromise has to be found between sample loading, injection volume and compatibility of the sample solvent and the initial phase system. Therefore,... 

Number of Polymer Chains. The quasiliving character of IBVE polymerization is further supported by quantitative analysis. Figure 4 illustrates changes in N, the number of poly(IBVE) chains produced per unit initiator (j>-DCC), as a function of WjbvE N is defined by eq. 2 ... 

Compared to flame excitation, random fluctuations in the intensity of emitted radiation from samples excited by arc and spark discharges are considerable. For this reason instantaneous measurements are not sufficiently reliable for analytical purposes and it is necessary to measure integrated intensities over periods of up to several minutes. Modern instruments will be computer controlled and fitted with VDUs. Computer-based data handling will enable qualitative analysis by sequential examination of the spectrum for elemental lines. Peak integration may be used for quantitative analysis and peak overlay routines for comparisons with standard spectra, detection of interferences and their correction (Figure 8.4). Alternatively an instrument fitted with a poly-chromator and which has a number of fixed channels (ca. 30) enables simultaneous measurements to be made. Such instruments are called direct reading spectrometers. 

Table II provides a summary of the results on the characteristics of aminopropyl terminated poly(dimethyl-diphenyl)-siloxane oligomers synthesized. These reactions were conducted in bulk at 160°C with K0H as the initiator. As can be seen from Table II the stoichiometric number average molecular weights sought and obtained are in very good agreement. The level of diphenylsiloxane incorporation was determined by UV spectroscopy. There is no absorption of dimethylsiloxane backbone in the spectral range of 240 to 280 nm. On the other hand, phenyl groups absorb very strongly over these wavelengths (Figure 3). For quantitative analysis we have used the absorption peak at 270 nm as the reference.

High resolution l3C NMR is also used in the determination of the composition of the dispersed phase in cured rubber modified epoxies in order to analyze the chemical structure of the mobile segments 152). In this case quantitative analysis is possible because the areas under each peak are approximately equal to the number of carbons contributing to the peak, and the intensities of the broad lines from the rigid phase are very low, almost indistinguishable from the baseline noise. The structure of crosslinked networks based on poly(3,4-pyrrolidinediethylene), synthesized by different methods, was determined from gels swollen in water and chloroform 153). 

J. Hoogmartens, Liquid chromatography for the quantitative analysis of antibiotics—some applications using poly(styrene-divinyl-benzene), J. Pharm. Biomed. Anal.,70 845 (1992). 

If the reaction mixture is contained in an internal poly(tetrafluoroethylene) cell transmitting IR radiation (see Sec. 6.7.2), quantitative analysis via high-pressure spectroscopy (Figures 6.7-16 to 6.7-18)) yields precise values of the rate coefficients of these Diels-Alder reactions. As an example, the pressure dependence of the rate coefficient k of the cycloaddition of 2 (with R = CF3) and 3 in CH2CI2 solution at 45 °C (Buback et al., 1989) is shown in Fig. 6.7-19. 

Test strips were prepared by oxidation of cellulose with KIO4 to a polyaldehyde, followed by condensation with 1-naphthylamine to a poly-Schiff base and reduction with NaBH4 to an immobilized naphthylamine cellulose derivative, which is mechanically stabilized on a polypropylene sheet. PAA can be detected on addition of nitrite to the test solution and contacting with the strip, where azo dyes are formed. Quantitative analysis can be carried out by diffuse reflectance spectroscopy. The method was applied to pharmaceutical preparations with RSD better than 30%246. 

Lee JW, Gardella JA. Simultaneous time-of-flight secondary ion MS quantitative analysis of drag surface concentration and polymer degradation kinetics in biodegradable poly(L-lactic acid) blends. Anal Chem 2003 75(13) 2950-2958. 

Numerical simulation of the ( H)- C spectra based on the given particle tumbling conditions allows for the quantitative analysis on a system which has undergone a partial phase transition. An example for the poly-e-caprolactone particles is shown in Fig. 24. 

The evidence for this mechanism is two-fold the presence of aromatic moiety in the resulting poly-glycol and the quantitative analysis of the solution left after precipitation of the polymer, demonstrating only one-half of the utilized naphthalenide being converted into naphthalene. (it has been claimed that at very low concentrations of the naphthalenide, polymers with only one growing group were formed ( 0), Hydrogen abstraction from solvent was proposed as an explanation. 

The analysis of acidic cell wall polymers (notably pectins) can also be complicated by their tendency to precipitate in acidic media. Jermyn and Isherwood (1956) found that aqueous solutions of pectic polymers from pear cell walls precipitated on the addition of nitric acid. If, however, the sample was warmed prior to the slow addition of acid, precipitation could be avoided. Ford (1982) has shown that quantitative analysis of water-soluble pectic polysaccharides can be improved by depolymerization with a poly-( 1,4-a-D-galacturonide)-glycanohydrolase (EC 3.2.1.15). This treatment can also be used prior to acid hydrolysis to prevent polymer aggregation. Although the recovery of neutral monosaccharides is increased, the stability of the glycosiduronic linkage still prevents its complete hydrolysis. 

Lee SC, Oh JT, Jang MH, Chung SI. Quantitative analysis of polyvinyl alcohol on the surface of poly(D, L-lactide-co-glycolide) microparticles prepared by solvent evaporation method Effect of particle size and PVA concentration. Journal of Controlled Release. May 20, 1999 59(2) 123-132. PubMed PMID 10332048. 

Other forces than H-bonding can lead to supramolecular polymer associations. Polymers such as PEG and sodium poly(a,L-glutamate) (PCNA) form complexes by ion-dipole and hydrophobic interactions. A quantitative analysis of the " Na-NMR spectra in D2O showed that only 6% of the sodium cations was complexed by PEG. while the majority of Na was in the solvated form. In nonaqueous media, a combination of Na and 2D-nuclear Gverhauser enhancement spectroscopy (NGESY) H-NMR suggests that the sodium ions are completely complexed by PEG through ion-dipole interactions. ... 

Remmers, M., Muller, B., Martin, K., Rader, H.-J., and Kohler, W., Poly(p-phenylene)s. Synthesis, Optical Properties, and Quantitative Analysis with HPLC and MALDI-TOF Mass Spectrometry, Macromolecules, 32, 1073,1999. Lee, H., Lee, W., Chang, T., Choi, S., Lee, D., Ji, H., Nonidez, W. K., and Mays, J. W., Characterization of Poly(ethylene oxide)-block-poly(L-lactide) by HPLC and MALDI-TOF Mass Spectrometry, Macromolecules, 32, 4143,1999. 

Paulussen, H., et al. 1997. Synthesis of poly(isothianapththene) from 1,1,3,3-tetrachlorothiophthalan and tert-butylmercaptan Mechanism and quantitative analysis by solid state NMR. Polymer 38 5221. 

The first quantitative analysis of RAF was carried out by analysis of the heat capacity of semicrystalline poly(oxymethylene), POM, as shown in Fig. 6.16 [20]. Clearly, the 67% of crystallinity computed from the heat of fusion, which would require a 33% amorphous fraction as indicated by the dotted line in the left trace, does... 

Finally, a semicrystalline extended-chain poly(oxyethylene) which melts almost completely irreversibly is shown in Figure 4.47. It is a specially perfect polymer, and more quantitative analyses of the less perfect polymers are detailed in Sections 4.2—4.5. This concludes Section 4.1 and sets the basis for a more quantitative analysis of the melting and crystallisation region of polymers. 

Infrared spectroscopy is also readily employed for the quantitative analysis of additives or contaminants in polymers. For example, Ihe amount of dioctyl phtha-late (DOP), a common plasticizer in poly(vinyl chloride) (PVC), may be determined by using the absorbance ratio of a 1460 cm band in the infrared spectrum of DOP and a 1425 cm band in the PVC spectrum. A calibration curve can be set up by using the infrared spectra of a series of PVC samples containing known values of DOP content the absorbance ratio, 1460 cm DOP/1425 cm PVC, versus concentration is then plotted. 

One potential area of application that has direct impact in polymer chemistry is the characterization of copolymers. The quantitative analysis of copolymer composition by MALDI has been demonstrated in a limited number of systems, though with varying degrees of success. For example. Abate et al showed that the relative amounts of hydroxybutyrate and hydroxyvalerate in a random copolymer, poly(P-hydroxybutyrate-co-P-hydroxyvalerate), when determined by MALDI, agree with those expected from theory [174]. Wilczek-Vera et al. have shown that for diblock... 

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