End groups titration

Determined by end-group titration b Average number of siloxane (Si—O) repeat units in the oligomer ... 

No carboxylic acid functionality was detected either by thin-layer chromatographic analyses or by end-group titration. Therefore, procedures are now available to control the carbonation of polymeric organolithium compounds to efficiently produce either the carbox-ylated chain ends or the corresponding ketone dimer. 

Figure 1.6 Changes in the viscosities of solutions of polyphosphates of different chain lengths on keeping for 12 h, where the abscissa represents the mean chain length as determined by end-group titration (a) immediately after solution (b) after keeping for 12 h (Strauss and Treitler, 1955b).

CR, cryoscopic method DV, diffusion constant and intrinsic viscosity EB, ebullioscopic method EG, end-group titration IV, intrinsic viscosity-molecular weight relationship in other solvents LS, light scattering MV, melt viscosity-molecular weight relationship OS, osmotic pressure PR, analysis of polymerization rate SD, sedimentation and diffusion constants SE, sedimentation equilibrium (Archibald s method) SV, sedimentation constant and intrinsic viscosity [see Eq. (72)]. 

Fraction Viscosity Osmotic Vapor Pressure End Groups Titration Number of Monomers Specific Activity gC/mg... 

Like many poly(dimethyl)siloxanes the functionally terminated (carboxy-propyl) polymer dissolves in a number of gases such as carbon dioxide, ethylene, and ethane. Table 9.32 gives the average molecular weight of the parent carboxypropyl-terminated poly(dimethyl)siloxane and the seven fractions derived from the parent by fractionation using supercritical carbon dioxide. The molecular weight analysis was carried out by end-group titration. As... 

Figure 1. van t Hoff plots demonstrating concentration dependence of pectin dissociation. Values at intercept calculated from end group titrations. 

DP from end group titration. Values for R were pooled data from... 

Comparison of number average lengths obtained from end group titration, 1 (EGT), and from size exclusion chromatography 1 (SEC)... 

Fishman, M.L. Pepper, L.A. Reconcilation of the Differences in Number Average Molecular Weights (M) By End Group Titration and Osmometry for Low Methoxy Pectins. In "New Developements in Industrial Polysaccharides" Dea, I.M. Crescenzi, V. and Stivala T. Ed. Gordon and Breach New York, 1985 pp 159-166. 

In a polyanhydride (a condensation polymer of a dicarboxylic acid) the end-group titration requires 36.72 mL of 0.008964 mol/L NaOH for 1.625 g of polymer. What is the average molar mass of the polymer ... 

K Vapor pressure osmometry End-group titration Proton NMR Boiling point elevation Freezing depression (cryoscopy) GPC... 

Typical molecular weight range g moP End group titration (1.6-4.0) X 10 (6)... 

The number average may be obtained by end-group titration or osmometry, the weight average by light scattering, and the viscosity average by viscometry of dilute solutions. 

In Fig. 13.4, the concentration of the amine end groups (determined by po-tentiometric end-group titrations) after blocking with succinic anhydride in CO2/IO mol% 1,4-dioxane is given vs time. 

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