Vapor Sorption and Solvent Probe Techniques

Inverse gas chromatography (IGC) and vapor sorption methods utilize solvent probes to ascertain the interactions existing in polymer blends These methods [357-359] employ the following equation for the activity coefficient of the probe, a, in the polymer blend  

This equation notes that the interaction between the probe and the blend is also a function of the interaction energy between the blend components. 

The procedure for IGC involves coating the stationary inert support material with the polymers and the blends and measuring the retention time according to GC protocols. The retention time is a function of the activity of the probe and can be used to qualitatively assess interactions in the polymer blend by employing probes such as hydrogen bonding, polar or non-polar probes. The key experimental parameter, V°, is the specific retention volume and is determined from  

Thus x 23 can be determined by combination of Eqs. 5.31 and 5.33. xn and xis need to be determined independently, thus a column each of the homopolymer components is required along with a column(s) of the blend(s). X23 can be determined directly from specific retention volume data on the three columns from  

One of the problems noted in several studies is that the results obtained by IGC are probe dependent. Further details on the experimental procedures and application to polymer blends can be found in [357-359]. 

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