曹堃课题组

Abstract

       A series of poly(styrene-alt-octadecyl maleimide)s [(alt)SNODMIs] with different molecular weights and molecular weight distributions were obtained through the reaction of octadecyl amine and poly(styrene-alt-maleic anhydride), which were synthesized using controlled free radical polymerization. The (alt)SNODMIs were assessed as flow improvers in two types of model waxy oils: one that was free of asphaltenes and one that contained asphaltenes. A differential scanning calorimeter, a polarizing microscope with a hot stage, and a rotational rheometer with parallel plate geometry were employed to characterize the crystallization temperature, the morphologies of the wax crystals and asphaltene particles, and the rheological behavior, respectively. The results indicate that the molecular weight and its distribution significantly affect the performance of the flow improver. In both model waxy oils, (alt)SNODMIs with a medium molecular weight achieved optimal effectiveness in decreasing the crystallization temperature, improving the morphology, and reducing the yield stress and viscosity. Moreover, (alt)SNODMIs with a narrower molecular weight distribution are more effective in the model waxy oil without asphaltenes, whereas the opposite result is found in the model waxy oil with asphaltenes.