Synthesis of Poly(maleic acid alkylamide-co-α-olefin-co-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-R-olefin-co-styrene) (MASC) with different ratios of styrene/R-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.

Synthesis of comb‐type copolymers with various pendants and their effect on the complex rheological behaviors of waxy oils

“…The yield stress here is defined as the stress below which the oil will not flow, which is able to be measured following our previous work . The sample is cooled from 90°C to the testing temperature (0°C for the model oil and 30°C for the crude oil) and then held at that temperature for 20 min.…”

Flow improvement of Liaohe extraheavy oil with comb‐type copolymers

“…To explore the effect of asphaltenes, asphaltenes extracted from the Liaohe extraheavy oils were added to the model oils (Table ). Interestingly, the τ y values of the model oils with asphaltenes (MO‐3 and MO‐4) were lower than those without asphaltenes (MO‐1 and MO‐2); this was probably because of the effect of the asphaltenes as natural pour‐point depressants (Figure ) . Upon the addition of the MACs, all of the τ y values were reduced, whereas the efficiency in the reduction of τ y weakened in the presence of asphaltenes.…”

“…The morphology of paraffin crystals from model oils was observed by polarizing light microscopy (Figures and ). After the dosage of MACs, the shape of paraffin crystals in the model oils changed from irregular to needlelike . In Figure , the paraffin crystals in MO‐1 without MACs appeared to form tightly packed leaflike particles.…”

“…To solve those problems, thermal, mechanical, and chemical methods are available. Among the previous methods, chemical methods by the feeding of polymer additives into crude oil have often been used with success …”

Well-Defined Alkyl Functional Poly(Styrene-co-Maleic Anhydride) Architectures as Pour Point and Viscosity Modifiers for Lubricating Oil

“…The space between pendent chains in graft copolymers was previously mentioned as a potential factor to improve PPD efficiency. 36 Moreover, the increasing content of styrene in structures with lower side chain density might influence the PPD solubility, resulting in lower efficiency, as polystyrene is barely soluble in oil. Because no obvious positive contribution was observed by spacing the side chains, and because their synthesis is more straightforward (one-step), further experiments were focused on alternating PSMA materials (see next section).…”