Size exclusion chromatography data

Norbornene-based and oxa-norbornene-based monomers bearing dendritic side chains, XXX and XXXI (Fig. 19), were synthesized and polymerized via ROMP with initiator 6 [83]. Based on size exclusion chromatography data, the polymerization shows hving-like character up to DP=70. H- and C-NMR-spectroscopy revealed 35% cis and 65% tram sequences. These polymers displayed enantiotropic nematic and smectic mesophases, except for DP=5. In contrast to other classes of SCLCPs, the dependence of the DP on the transition temperatirre of the polymer was very weak. Glass transition and isotropization temperatures became independent of molecular weight above a degree of polymerization of about 10. 

Universal calibration curve for size exclusion chromatography. Data points are polybutadienes in tetrahydrofuran at 25 °C in crosslinked polystyrene columns. There is a reasonably linear region of the calibration curve spanning the data (solid line) but the linear region has its limits (dotted curves). 

Table 5.2 Light scattering, photon correlation spectroscopy, viscosity and size-exclusion chromatography data of a fractionated random copolyester (for structure and composition see text) in BTFMP at 60 C [8]... 

Table 12.1 Size Exclusion Chromatography data on PLA and nanocomposites before and after degradation in neutral phosphate buffered solution at 37 °C and 58 °C. Data extracted from Fukushima et al., with permission from Elsevier.

Since cyclohexane is a solvent for PS at the operating temperature of 80 C, the conversion is more moderate than the system that only had MAA as second-stage monomer charge. The final product from the 300-ml Parr reactor system was dried out and a dry sample was dissolved in THF. Water was added in as precipitant for the purified block copolymer. The unprecipitated block copolymer was called the raw product. In Fig. 3.2.2, size exclusion chromatography data are shown for the intermediate PS, raw block copolymer product, and purified copolymer product. 

Theodore Provder, Editor. (1987). Detection and Data Analysis in Size Exclusion Chromatography, ACS Symposium Series. 

Barth, H. G. (1987). 1 ACS Symposium Series 352, Detection and Data Analysis in Size Exclusion Chromatography (T. Provder, ed.), pp. 29-46. American Chemical Society, Washington, DC. 

A new direct method for using size exclusion chromatography (SEC) to evaluate polymer intrinsic viscosity [n] is discussed. Sample viscosity information is obtained by combining SEC elution curve data and calibration data using direct SEC-[n] calibration procedures without involving polymer molecular weight calculations. The practical utility, convenience and the expected precision of the proposed method are illustrated. 

Novolac molecular weights were measured in THF at 35°C by high pressure size exclusion chromatography using a Waters Model 510 pump (flow rate=1.0 ml/min), 401 differential viscometer detector and a set of Dupont PSM 60 silanized columns. A universal calibration curve was obtained with a kit of 10 narrow molecular weight distribution, linear polystyrene standards from Toya Soda Company. Data acquisition and analysis were performed on an AT T 6312 computer using ASYST Unical 3.02 software supplied with the Viscotek instrument. 

Values from size exclusion chromatography (SEC) data obtained at 25°C in 0.1 molar citric acid in water. 

It should be noted that discrepancies amidst available data may result from different methods of determination. For example, selected hydrodynamic radii of PAMAM dendrimers of Table 14.1 were obtained by two different experimental methods for generations 1 through 4 by dilute solution viscometry, while for generations 5 through 10 by size exclusion chromatography. 

The data prove that the retention order of anthocyanins deviates from each other in HPLC and TLC suggesting the involvement of a different retention mechanism. It was stated that the preseparation of anthocyanins by size-exclusion chromatography is a prerequisite of the successful preparative separation by RP-HPLC [244],... 

For PAMAM dendrimers, the molecular dimensions were determined by size-exclusion chromatography and the dimensions of PPl dendrimers were determined by SANs data for the high-generation PPl dendrimers are not available. 

In the first section, the mechanisms involved in size exclusion chromatography are discussed this is an area where additional understanding and clarification still are needed. Data treatment with respect to statistical reliability of the data along with corrections for instrumental broadening is still a valid concern. Instrumental advances in the automation of multiple detectors and the developm.ent of a pressure-programmed, controlled-flow supercritical fluid chromatograph are presented. 

It must be kept in mind, however, that CE data resemble a macroscopic effect of complexation and, like ultrafiltration or size exclusion chromatography CE, do not give information on specific binding sites. Despite the existence of a well-established theoretical basis, it is not possible to get reliable complexation constants, for practical reasons, if too many complexation processes are involved at the same time. Often the combination with spectroscopic investigations, especially with NMR and fluorimetry, may provide more details. 

HE FIELD OF SIZE EXCLUSION CHROMATOGRAPHY (SEC) remains a viable and lively area of polymer characterization. Over the past several years, there has been considerable research activity in the area of SEC detection and data analysis in order to obtain more comprehensive information concerning the composition and molecular architecture of complex polymer systems. 

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