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Handbook of Size Exclusion Chromatography and Related ...

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Figure 2 Typical GPC calibrations with PS (Q ¼60:4g/A ˚ )<strong>and</strong> PI molecular weight<br />

st<strong>and</strong>ards. Instrument: Waters Model 244. Column: 10 6 ,10 5 ,10 4 ,10 3 , 500A ˚ porosities.<br />

Mobile phase: THF. Flow rate: 1mL/min. Temperature: 278C. Detector: RI. (From Ref. 6.)<br />

been obtained by this method; they cannot be obtained with other methods<br />

because <strong>of</strong> their complex behavior in SEC solvent.<br />

It is not always necessary to calculate the correct molecular weight<br />

distributiontoobtaininformationfromSECchromatograms.Simpleinspection<strong>of</strong><br />

chromatograms <strong>of</strong>ten reveals important information, as shown in Fig. 3. The<br />

comparison is valid only for data obtained under the same SEC conditions,<br />

however, because an SEC chromatogram is a function <strong>of</strong> molecular weight<br />

© 2004 by Marcel Dekker, Inc.<br />

Table 4 Molecular Weight<br />

St<strong>and</strong>ards for SEC Analysis <strong>of</strong><br />

Rubbers<br />

Polybutadiene<br />

Polyisoprene<br />

Polyisobutylene<br />

Polystyrene-isoprene diblock<br />

Polystyrene-butadiene diblock<br />

Polystyrene-butadiene star block<br />

Source: Ref. 71.

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