How comb-type poly(maleic acid alkylamide-co-α-olef in) assemble in waxy oils and improve flowing ability

摘要

Wax deposition in pipelines restricts flow and even leads to plugging during oil transportation. This paper aims to improve the flowing ability of cold waxy oils using comb-type copolymers to interact with main components of waxy oil: long-chain n-paraffins and asphaltenes. A series of comb-type poly(maleic acid alkylamide-co-α-olerin) (MAC) with different side-chain lengths were synthesized by copolymerization of α-olefin and maleic anhydride followed by amidation with alkylamine. Their effects on the rheological property (yield stress) and crystallization behaviors of both model waxy oils and crude oils were observed by rheology, differential scanning calorimetry (DSC), and optical microscopy. MACs reduced the yield stress of oils and the crystal size of long-chain n -paraffins, and improved the flowing ability of oils at 0 ℃ significantly. The MACs either self-assemble to nucleate the crystallization of long-chain n-paraffins or co-crystallize with them by the nonpolar side chains and inhibit the growth of paraffin crystals by the layer of the polar parts, while the carboxyl and amide groups interact with polar aromatic asphaltenes to prevent their aggregation upon cooling.