Synthesis of Poly(maleic acid alkylamide-<i>co</i>-α-olefin-<i>co</i>-styrene) Co-polymers and Their Effect on the Yield Stress and Morphology of Waxy Gels with Asphaltenes

Abstract

To examine the effect of aromatic units in a polymer on the crystallization behaviors of waxy gels with a low content of asphaltenes, new comb-type co-polymers of poly(maleic anhydride- co -α-olefin- co -styrene) (MASC) with different ratios of styrene/α-octadecene were designed and synthesized. 1 H nuclear magnetic resonance (NMR) spectra were obtained to characterize the chemical structure of the co-polymers. Solubility and melting point tests were also performed to confirm the as-synthesized MASC co-polymers. The effect of co-polymers on the yield stress of model oils with and without asphaltenes was studied by means of rheology. The morphology of wax crystals was observed by polarizing light microscopy. Upon the addition of MASCs to the model waxy oil, the yield stresses decreased with the increase of aromatic units in MASC chains while increased when 0.1% asphaltenes were added. The morphology of model waxy oil with 0.1% asphaltenes was also changed with the content of aromatic units in MASC. A higher content of aromatic units in MASC and a higher amount of MASC lead to a smaller size of wax crystals.