DISCOTIC SHAPE OF ASPHALTENES OBTAINED FROM GPC DATA

A simple procedure, based on the calibration lines of polystyrene (PS) and octylated asphaltenes (OA) standards, is proposed. The theoretica l ratio between the slopes of these lines (B = 1.18) was close to the experimental (1.218) and to others in the literature when a disc shape for the AS is assumed. By assuming a disc shape for the asphaltenes, a thickness, sigma, of 0.373 +/- 0.016 nm was found. This value is ver y close to others reported in the literature using the small angle X-r ay scattering (SAXS) technique.