Molecular size calculation oligomers

We have recently reported (1 )) the use of this technique for characterization of various compounds. Experimental data obtained for a number of compounds are shown in Figure 2. We calculated the "size factors" for a number of small molecules and oligomers. This factor is a measure of the deviation of the elution volume of a given species from the calibration curve for n-alkanes which is assigned a size factor of 1. This size factor, F, is defined to be equal to A/M, where M is the molecular weight of the compound and A is the molecular weight of a real or hypothetical n-alkane which will elute at the same retention volume as the compound. Size factors for a number of... 

The titration-determined molecular weights of the individual samples were used to calculate the amount of benzophenone required to completely derivatize the amine functionalities. A 10 mol % excess of benzophenone was used to ensure complete derivatization. The reaction was done in bulk at 80 °C by heating the siloxane oligomer and benzophenone for 24 h in the presence of 3-A molecular sieves. GPC analysis was then carried out at 30 °C with a Waters 590 GPC apparatus equipped with ultrastyragel columns with particle sizes of 500, 10, 10", and 10" A. A Waters 490 programmable wavelength detector set at 218 nm was used with THE (tetrahydro-fiiran) as the solvent. 

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