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Handbook of Size Exclusion Chromatography and Related ...

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thepartiallyhydrolyzedPVAwiththecolumnpacking(1).TheMark–HouwinkK<br />

<strong>and</strong> avalues calculated from TDS measurements (Table 3) fallwithin arelatively<br />

narrow range (0.602–0.631). Only the super-low, partially hydrolyzed grade<br />

exhibits an avalue outside that range (0.645). The log(K) values fall in the<br />

range 23.124 to 23.265, except for the super-low, partially hydrolyzed PVA<br />

grade, which shows log(K) ¼23.306. The log(K) <strong>and</strong> avalues appear to be<br />

independent <strong>of</strong> molecular weight <strong>and</strong> degree <strong>of</strong> hydrolysis.<br />

Table 4shows asummary <strong>of</strong> the average log(K) <strong>and</strong> avalue for partially<br />

hydrolyzed <strong>and</strong> fully hydrolyzed PVAfrom this study <strong>and</strong> four other published<br />

works (11–14). The values obtained from TDS compare quite favorably to these<br />

published values, except for Ref. (11). That work utilized on-line viscometry <strong>and</strong><br />

universalcalibration withaqueous SECtodetermine K<strong>and</strong>aforfullyhydrolyzed<br />

PVA. The value for afrom universal calibration is somewhat lower than that<br />

obtained from TDS, 0.560 vs. 0.611. The TDS results may challenge how well<br />

universal calibration behavior was in force in the previous study (11).<br />

TDS provides an effective means to measure radius <strong>of</strong> gyration (Rgz) <strong>and</strong><br />

conformation <strong>of</strong> PVA. Overlays <strong>of</strong> the conformation plots (log–log plot <strong>of</strong> RMS<br />

radius vs. molecular weight) for the five partially hydrolyzed molecular weight<br />

grades <strong>of</strong> PVA<strong>and</strong> the four molecular weight grades <strong>of</strong>fully hydrolyzed PVAare<br />

shown in Fig. 8. As was observed for the Mark–Houwink plots in Fig. 7, the<br />

curves for the fully hydrolysed PVAs fall right on top <strong>of</strong> each other with virtually<br />

no variation. The curves for the partially hydrolyzed PVAs show slighter more<br />

scatter.<br />

Table 5summarizes a comparison <strong>of</strong> Rgz values obtained from TDS <strong>and</strong><br />

MALLS. The MALLS data show both Rgz values from the Mini–Dawn tripleangle<br />

detection <strong>and</strong> the Wyatt Technology Dawn-F multi-angle detection. The<br />

Dawn-F data are from Ref. 2. Over the full range <strong>of</strong> molecular weights used for<br />

both partially <strong>and</strong> fully hydrolyzed PVA, the Rgz values range from 6.5 to 20.4 nm.<br />

© 2004 by Marcel Dekker, Inc.<br />

Table 4 Summary <strong>of</strong> Mark–Houwink Constants for PVA<br />

PVA type a log(K)<br />

Partially hydrolyzed<br />

This study 0.625 23.325<br />

Fully hydrolyzed<br />

This study 0.611 23.119<br />

Ref. 11 0.560 22.875<br />

Ref. 12 0.61 23.161<br />

Ref. 13 0.62 23.052<br />

Ref. 14 0.64 23.125

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