Size exclusion chromatographic analyses

Number-average molecular weights were determined in toluene solutions using a membrane osmometer (Mechrolab, Hewlett-Packard 503 with S S-08 membranes). Size exclusion chromatographic analyses in chloroform were performed by HPLC (Perkln-Elmer 601 HPLC) using two y-Styragel columns (lO", 10 A) after calibration with standard polystyrene samples. 

Poly(styryl)lithium (> 15,000) In benzene solution was reacted with excess ethylene oxide In the presence of N,N,N, N -tetramethyl-ethylenedlamlne (TMEDA, [TMEDA]/[Li] 3.2). After 12 days at 25-30 C, size exclusion chromatographic analyses Indicated no significant ethylene oxide polymerization. Hydroxyethylated polystyrene was recovered in essentially quantitative yleU. 

Size exclusion chromatographic analyses showed that a microbial community incubated with chitosan at 20°C yielded polymers with a weight average molecular weight (M ) of 7.8 kDa [46] this was a sharp decrease from the initial of the chitosan that was 261 kD. Based on size exclusion... 

The validity of a practical method of direct viscosity calculation from size exclusion chromatographic analysis is demonstrated. The method is convenient to use and is not limited by the availability of narrow MWD standards. It is possible to accurately measure polymer Mark-Houwink constants using the suggested broad standard SEC-[n] and SEC-MW calibration procedure. 

Anionic thesis of macromonomer of 1,1-diphenylethylene-type unit canying amino group has been performed in a variety of solvents. The product was characterized a combination of H NMR spectroscopic and size exclusion chromatographic analysis. Based on the UV/Visible spectroscopic analysis, the crossover reaction of /i-butyllithium (n-BuLi) with l-[4-bis(trimethylsilyl>amino]phenyl]-l-phenylethylene was found to be so slow in benzene, but it was completed in the benzene/THF mixture within 2 h. The i thesis of macromonomer of thel,l-diphenylethylene-type unit (over 95 %) canying amine-functional group (maximum 94 %) was successful on the basis of H NMR spectroscopic analysis. 

Figure 4 Size exclusion chromatographic analysis of the mixture of oligoimides 31 (Fig. 15) at various degrees of poly condensation in solution at 105°C in benzyl alcohol.

Inverse Size Exclusion Chromatographic (ISEC) Analysis of Solvent Wetted Polymer Supports... 

The automation of the SEC/Viscometer detector system is achieved by interfacing the DRI and viscosity detectors to a microcomputer for real time data acquisition. The raw data subsequently are transferred to a minicomputer (DEC PDP-11/44) for storage and data reduction. The automated data acquisition and analysis system for the size exclusion chromatograph with multiple detectors used in this study have been described previously.(23)... 

Upnmoor and Brunner [7] evaluated a packed column SFC with a light scattering detector using a mobile phase of carbon dioxide modified with methanol for the chromatography of polymer additives. Moulder and co-workers [8] transferred eluent fractions from a packed capillary size exclusion chromatographic (SEC) column using a solvent vented interface to an open tubular CSFC column. The system was evaluated for the analysis of polymer additives. 

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