Applications of SFC to polymers and polymer-related materials

Generally the resolution obtainable by SEC is poor, and analysis times tend to be excessively long. Seldom is it possible to fully resolve oligomeric species within the polymer, making calibration of molecular mass v. composition difficult. However, above an average molecular mass of 10 daltons, SEC is the only chromatographic technique available. 

Until the advent of SFC, there has been an analytical gap in the molecular mass range extending above the GC molecular weight range, which LC did not always satisfy. It is within this 10 -10 range that SFC excels. This is particularly true for oligomers and many polymeric raw materials. For example, polyols, used in the manufacture of many polyesters and polyurethanes, are seldom volatile enough for GC, nor do they necessarily contain a chromophore for LC, and they are excluded by SEC due to their low molecular mass [37]. 

Many polymers have been analysed by SFC, namely styrene and vinyl oligomers, polysiloxanes, polysaccharides, polyethers, polyesters, polyolefins and waxes, and low-molecular mass epoxy, acrylate and isocyanate oligomers. Each type of polymer will be dealt with in a separate subsection. A summary of polymer applications by SFC is listed in Table 9.3. 

---