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Handbook of Size Exclusion Chromatography and Related ...

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method for the study <strong>of</strong> the molecular characterization <strong>of</strong> rubbers. At present,<br />

the term “size exclusion chromatography” (SEC) is more frequently used than<br />

GPC, <strong>and</strong> this is becoming much more refined in both hardware <strong>and</strong> s<strong>of</strong>tware, as<br />

described elsewhere.<br />

It is always necessary to dissolve the rubber sample in SEC solvents before<br />

SEC analysis. Natural rubbers as well as many synthetic rubbers are mainly<br />

composed <strong>of</strong> diene <strong>and</strong> vinyl units <strong>and</strong> are in an amorphous solid state. Therefore,<br />

in general, no problems are encountered when performing SEC measurements.<br />

Much data for SEC for rubbers have been obtained. These data are listed in the<br />

Appendix to this chapter to provide SEC experimental conditions, <strong>and</strong> some<br />

consideration is given here to the SEC analysis <strong>of</strong> rubbers.<br />

2 CLASSIFICATION OF RUBBERS<br />

In addition to natural rubber, many synthetic rubbers are now commercially<br />

available. Although there are several ways to classify these rubbers, the American<br />

Society for Testing <strong>and</strong> Materials (ASTM) St<strong>and</strong>ard D1418-85 gives the<br />

classification <strong>and</strong> designation <strong>of</strong> rubbers based on their chemical composition.<br />

Therefore, in this chapter, the classification <strong>and</strong> naming <strong>of</strong> rubbers are based on<br />

this st<strong>and</strong>ard. For convenience, the nomenclature is reproduced in Table 1,<br />

extracted from the st<strong>and</strong>ard.<br />

Table 1 Abbreviation <strong>of</strong> Rubbers According to ASTM D1418-85<br />

ABR acrylate-butadiene<br />

BR butadiene<br />

CIIR chloro-isobutene-isoprene<br />

CR chloroprene<br />

IIR isobutene-isoprene<br />

IR isoprene, synthetic<br />

NBR nitrile-butadiene<br />

NCR nitrile-chloroprene<br />

NIR nitrile-isoprene<br />

NR natural rubber<br />

SBR styrene-butadiene<br />

SCR styrene-chloroprene<br />

SIR styrene-isoprene rubbers<br />

Z polyorganophosphazene<br />

Q polysiloxane rubber<br />

FKM fluoro rubber <strong>of</strong> polymethyrene type having substituent fluoro <strong>and</strong><br />

perfluoroalkoxy groups on the polymer chain<br />

© 2004 by Marcel Dekker, Inc.

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