Styrene acrylonitrile copolymers size exclusion chromatography

Figure 12.8 Microcolumn size exclusion chromatogram of a styrene-acrylonitrile copolymer sample fractions transferred to the pyrolysis system are indicated 1-6. Conditions fused-silica column (50 cm X 250 xm i.d.) packed with Zorbax PSM-1000 (7 j.m dty, eluent, THF flow rate, 2.0 xL/min detector, Jasco Uvidec V at 220 nm injection size, 20 nL. Reprinted from Analytical Chemistry, 61, H. J. Cortes et al., Multidimensional chromatography using on-line microcolumn liquid chromatography and pyrolysis gas chromatography for polymer characterization , pp. 961 -965, copyright 1989, with permission from the American Chemical Society.

Mori S (1996) Characterization of styrene-acrylonitrile copolymers by size exclusion chromatography/stepwise gradient elution-liquid precipitation chromatography. Int J Polym Anal Charact 2 185-92. 

UV Spectrophotometers as Detectors for Size Exclusion Chromatography of Styrene-Acrylonitrile (SAN) Copolymers... 

The application of UV spectrophotometers to the analysis of styrene containing copolymers has been extensively reported in the literature. However, hypochromic effects and band shifts which result in deviations from Beer s Law have limited the use of UV detectors as mass or composition detectors in size exclusion chromatography applications. Deviations from Beer s Law for low conversion styrene-acrylonitrile copolymers in tetrahydrofuran have been experimentally investigated and compared with results previously reported in the literature. The behaviour of the extinction coefficient as a function of the copolymer composition is discussed in view of the information obtained from infrared and nuclear magnetic resonance measurements on the same polymers. As a result of this investigation, a quantitative correlation of the extinction coefficients of styrene-acrylonitrile copolymers with the length of the styrene sequences has been obtained which, in turn, allows for the use of UV spectrophotometers as sequence length detectors. 

Refractive index and specific refractive index increments - (k = dn/dc) of polymers in solution have been studied extensively in connection with light scattering measurements and size exclusion chromatography applications to polymer characterization for which refractometers are used as standard concentration detectors. Contrary to the observations made in the infrared region (12), refractive index increments have been shown to be a function of the molecular weight of the polymers (2) and, in some cases, of the copolymer composition (17). Therefore, the assumptions of linearity and additivity (Eq. 1 to 4) have to be verified for each particular polymer system. In the case of styrene/acrylonitrile copolymers, there is an additional uncertainty due to the... 

Gloeckner, G., J. H. M. van den Berg, N. L. T. Meijerink, T. G. Scholte, and R. Koningsveld. 1984. Size exclusion and high-performance precipitation liquid chromatography of styrene-acrylonitrile copolymers. Macromolecules. 17 962-967. 

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