Stockmayer-Fixman plot

Fig. 26. Stockmayer-Fixman plots for PBLA in three helix-breaking solvents, constructed from the data by Hayashi et al. (22)...

Fig. 4. Stockmayer-Fixman plot for isotactic polyjpentene-l)38) (A) toluene at 30 °C ...

Figure 3. Molecular-weight dependence of intrinsic viscosity of dextran in water (O) and methanol-water mixture with a methanol mole fraction of 0.228 (9) at 25°C (4, 21)t (a) log [r]] — log plots (b) Stockmayer-Fixman plots.

Figure 9-27. Burchard-Stockmayer-Fixman plot for poly(cyclohexyI methacrylate) in benzene and cyclohexane at 25° C and in butanol at 23° C (according to N. Hadjichristidis, M. Devaleriola, and V. Desreux).

FIGURE 10.1 Stockmayer-Fixman plots, reconstructed from published Mark-Houwink parameters, illustrating inconsistencies in the PLA literature. Rather than the wide range of values exhibited, the y-axis intercepts should be a common value equal to K . 

FIGURE 10.2 Stockmayer-Fixman plots for three separate solvents from the study of Dorgan et al. showing consistency of the determined Kq values (contrast with Figure 10.1). 

Much of the above discussion indicates that, to study excluded volume effects, an accurate determination of unperturbed dimensions is required. For this, a common procedure is to extrapolate intrinsic viscosity of known molecular weight samples to zero molecular weight. Several extrapolations have been used, notably the Stockmayer-Fixman plot. Dondos and Benoit have now introduced a modified version of this, which appears to be linear over a wider range of molecular weights. It introduces a parameter D, which is shown to be linearly related to the exponent of the Mark-Houwink-Sakurada equation. 

Figure 30 Plots of g, (panel a) and (panel b) against ffor the same polymer+solvent systems as in Figure 29. The lines in panels a and b represent Zimm and Kilb s and Stockmayer and Fixman s theoretical values, respectively. Symbols are the same as those used in Figure 29.

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