Calibration of High Performance size Exclusion Chromatography for Small Epoxy Molecules

Abstract

Many epoxy resin formulations contain small oligomers (e.g., less than 1000 molecular weight units) as left over starting materials, reaction by products, or as active parts of the formulation. Modern high performance size exclusion columns are available which enable molecular weights of these oligomers to be determined if proper calibration techniques are employed. Data are presented which demonstrate the differences in calibration curves for epoxy molecules and polystyrene standards, n-alkanes, and phthalate esters for molecular weights under 1000 g/mole. Low MW epoxies are used to calibrate directly for epoxies rather than using molecular size conversion factors calculated from other standards such as polystyrenes.